WO2023036270A1 - 抗原靶向、抗cd16a和免疫效应细胞激活三功能融合蛋白及其应用 - Google Patents

抗原靶向、抗cd16a和免疫效应细胞激活三功能融合蛋白及其应用 Download PDF

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WO2023036270A1
WO2023036270A1 PCT/CN2022/117940 CN2022117940W WO2023036270A1 WO 2023036270 A1 WO2023036270 A1 WO 2023036270A1 CN 2022117940 W CN2022117940 W CN 2022117940W WO 2023036270 A1 WO2023036270 A1 WO 2023036270A1
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cd16a
taa
binding
peptide chain
variable region
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French (fr)
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屈向东
潘琴
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Qure Biotechnology Shanghai Co Ltd
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Qure Biotechnology Shanghai Co Ltd
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Priority to JP2024515525A priority Critical patent/JP2024534982A/ja
Priority to US18/690,834 priority patent/US20240383985A1/en
Priority to EP22866731.7A priority patent/EP4400518A4/en
Publication of WO2023036270A1 publication Critical patent/WO2023036270A1/zh
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    • C07K16/283—Immunoglobulins [IG], e.g. monoclonal or polyclonal antibodies against material from animals or humans against receptors, cell surface antigens or cell surface determinants against the immunoglobulin superfamily against Fc-receptors, e.g. CD16, CD32, CD64
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Definitions

  • the invention relates to the technical field of biomedicine, in particular to a trifunctional fusion protein of antigen targeting, anti-CD16A and immune effector cell activation and application thereof.
  • Natural killer cells are natural immune cells that are very effective at destroying stressed cells, such as virally infected or tumor-transformed cells. NK cells have functions such as cytotoxicity, cytokine production, and immune memory that are not restricted by MHC, making them a key player in the immune response system.
  • Antibody-dependent cell-mediated cytotoxicity is a potent cytotoxic mechanism mainly mediated by natural killer (NK) cells. ADCC through CD16a is one of the main mechanisms of NK cell anti-tumor effect. When specific antibodies bind to the membranes of targeted tumor cells, immune cells respond by inducing cell death.
  • FcR Fc receptor
  • the IgG FcR family Fc ⁇ R
  • CD16a mainly triggers NK cell-mediated ADCC.
  • the ADCC effect mainly activates NK cells through antibodies that bind to Fc ⁇ RIII (CD16).
  • Human NK cells are divided into two major subsets: CD56bright and CD56dim.
  • CD56bright NK cells are potent cytokine producers but lack CD16a; whereas CD56dim are highly cytotoxic and express CD16a.
  • NK cells Upon recognition of an IgG-opsonized target via CD16a, NK cells release different cytotoxic molecules that trigger the death of the target cell. This mechanism relies on the formation of the immune synapse and degranulation of soluble granules containing perforin and granzymes.
  • NK cells can also clear target cells by binding target death receptors (such as DR4, DR5, or Fas) to their death receptor ligands (such as FasL and TRAIL).
  • target death receptors such as DR4, DR5, or Fas
  • CD16a is a transmembrane receptor with a short C-ter cytoplasmic tail and has two extracellular Ig-like domains. CD16a interacts with CH2 of IgG in a 1:1 manner, and the N-glycan chain at position N297 on CH2 also plays a key role in this interaction. CD16a lacks an ITAM domain in its cytoplasmic tail and thus requires the help of the tandem of two intracellular chains containing ITAM domains, CD3 ⁇ and Fc ⁇ RI ⁇ . Upon CD16a binding, the kinase Lck belonging to the Src family is activated and phosphorylates the ITAM domain of CD3 ⁇ and/or Fc ⁇ RI ⁇ .
  • Phosphorylated ITAMs allow the recruitment and phosphorylation of kinases from the Syk family, such as Syk and ZAP-70, which in turn are responsible for subsequent signalling.
  • PI3K is highly related because it converts PIP2 to PIP3, which releases IP3 and DAG upon PLC- ⁇ treatment. DAG activates the PKC family, which helps trigger degranulation.
  • IP3 induces calcium release from the endoplasmic reticulum, and this calcium influx is one of the main signals triggered by ADCC, which also leads to the translocation of NFAT in the nucleus and induces the transcription of its target genes.
  • Other pathways that CD16a is involved in activation also contribute to ADCC, such as the ERK2MAPK pathway.
  • CD16a is rapidly downregulated following CD16a-dependent NK cell killing.
  • One of the mechanisms of CD16a shedding is mediated by disintegrin and metalloproteinase 17 (ADAM17), which is expressed on NK cells. Cleavage of CD16a by ADAM17 occurs in cis, implying that NK cells expressing ADAM17 cannot induce CD16a shedding on another NK cell.
  • Another mechanism by which CD16a is downregulated upon activation is internalization, which occurs not only on CD16a but also on other intracellular signaling components such as CD3 ⁇ , ZAP-70 and Syk.
  • NK cells as killer cells in innate immune cells, can directly kill pathogens and tumor cells. Compared with T cells, NK cells have stronger tumor recognition and killing capabilities, as well as stronger potential for off-the-shelf applications.
  • ADCC enhance antibody-dependent cytotoxicity
  • ADCC antibody-dependent cell-mediated cytotoxicity
  • the strategies to improve the role of ADCC are mainly from the following aspects:
  • Cytokines A simple way to increase ADCC activity is to stimulate NK cells with pro-inflammatory cytokines.
  • NK cell transplantation has been successfully performed in several clinical trials, for example by infusion of cytokine-induced memory-like (CIML) NK cells, the most commonly used combination of cytokines including IL-12, IL-15 and IL-18.
  • CIML NK cells express more IFN- ⁇ than conventional NK cells and exhibit superior cytotoxicity against leukemia cells and primary acute myeloid leukemia (AML) blasts.
  • IL-12 increases the production of IFN- ⁇ and TNF- ⁇ by NK cells.
  • NK cells from patients with PFS greater than 100 days had higher ADCC activity in vitro compared with patients with progression-free survival (PFS) less than 100 days.
  • PFS progression-free survival
  • IL-15 is an essential cytokine for the survival and function of NK and CD8+ T cells.
  • N-803 is a mutant N72D IL-15 superagonist that has shown enhanced NK cell activity in vitro and in vivo in preclinical models and clinical trials. In addition, it increased the number of NK and CD8+ T cells.
  • ADAM17 is the main driver of CD16a downregulation upon activation.
  • One strategy to improve NK cell ADCC is to prevent CD16a shedding by targeting ADAM17.
  • some studies have also shown that blocking ADAM17 reduces the survival rate of NK cells and CD16a-mediated serial killing, and the cells cannot be separated from the target cells, hindering their movement to another target cell.
  • the benefits of ADAM17 inhibition are unclear and results are controversial.
  • the success of this strategy is pending the results of an ongoing clinical trial (NCT04023071) that will evaluate iPSC-derived NK cells bearing non-cleavable CD16a in AML and B-cell lymphoma.
  • Engineered antibody The Fc part of the antibody is engineered to increase the affinity of Fc to CD16a and subsequently improve ADCC.
  • Some mutations are very prevalent, for example, the so-called GASDALIE, consisting of 4 substitutions in Fc: G236A/S239D/A330L/I332E. This mutation showed a significant increase in affinity for CD16a, but little increase in CD32b affinity.
  • glycoengineering of antibody Fc N-glycans is expected to increase the affinity for CD16a.
  • the most studied sugar modification is deglycosylation, such as defucose modification. This modification leads to increased binding to CD16a and improved ADCC. This technique has been used with the anti-CD20 antibody obinutuzumab.
  • NK cell engager In addition to engineered antibodies, the form of antibodies can also be studied. Building on the success of the bispecific T cell engager (BiTE) strategy, an analogous format was developed for NK cells, the so-called bispecific killer cell engager (BiKE). BiKE consists of two scFvs via a linker sequence, one scFv targeting CD16a and the other targeting a tumor antigen. In addition, there is the Trispecific Killer Cell Engager (TRiKE), where 2 tumor antigens are targeted together with CD16a, or IL-15 is added instead of a third scFv. The use of this construct allows NK cells to relocate to tumor cells and leads to a robust ADCC effect against target cells.
  • TRiKE Trispecific Killer Cell Engager
  • AFM13 is a bispecific antibody against CD16a and CD30, which is currently in clinical phase II for the treatment of peripheral T-cell lymphoma, transformed mycosis fungoides and Hodgkin's lymphoma.
  • AFM13 and pembrolizumab produced an objective response rate of 88% and an overall response rate of 83%.
  • GTB-3550 a TRiKE form of CD16/CD33/IL-15, is currently being studied in a Phase I/II trial in multiple types of leukemia (NCT03214666).
  • NK cells are found in the tumor microenvironment in most tumors including intestinal cancer, renal cancer, liver cancer, breast cancer and lung cancer. Therefore, the industry has developed an immunotherapy method that uses the activity of CD16A to treat cancer, such as bispecific molecules formed by antibodies specific to tumor surface antigens and CD16A specific antibodies on NK cells.
  • HER2/neu and CD16A bispecific antibody has stronger anti-tumor activity than HER2 antibody alone; AFM13, a bispecific antibody that specifically binds CD16A and CD30, binds to CD16 molecules on the surface of NK cells or monocytes, enabling These immune effector cells target tumor cells expressing CD30, and the antibody was shown to clear tumors in mouse models of Hodgkin's tumor as well as in patients.
  • the exposure of traditional CD16A antibody or anti-CD16A antigen-binding protein for a period of time will lead to NK cell exhaustion or the reduction of NK cell cytotoxicity, thereby affecting the tumor killing effect of NK cells.
  • the CD16A double antibody cannot be administered for a long time, which affects its effect.
  • Interleukin-15 is a 14–15kDa cytokine that is important for the function of NK cells, NKT cells and memory CD8+ T cells.
  • IL-15 combines with its receptor IL-15R ⁇ to produce a complex IL-15 superagonist (IL-15SA) with extremely high biological potency, which is then transduced and transported to target cells.
  • IL-15SA strongly activates cells expressing IL-15R in response, especially NK cells/T cells, thereby promoting antitumor and antiviral functions.
  • IL-15 has a wide range of immunoregulatory effects, and can participate in the regulation of the survival, proliferation and function of T cells, especially NK cells and memory CD8+ T cells.
  • IL-15 is very similar to IL-2 in structure, and both belong to the helical cytokine family.
  • the heterotrimeric receptor for IL-15 shares the IL-2R/IL-15R ⁇ (CD122) and common ⁇ c chain (CD 132) with the IL-2 receptor, due to these common receptor components and shared JAK 1/JAK 3 /STAT 5 signaling pathway, IL-15 and IL-2 have the same functions, including stimulating T cell proliferation, generating cytotoxic T lymphocytes, stimulating B cells to synthesize immunoglobulins, and NK cell production and continued survival.
  • IL-2 and IL-15 have distinct and often competing roles in many adaptive immune responses. There are four main points: 1. IL-2 can regulate the activation of Tregs cells, but IL-15 cannot. 2.
  • IL-2 can suppress T cell responses by activating the induced cell death of CD8+ effector T cells.
  • IL-15 plays an essential role in the differentiation of NK, effector CD8+ and memory phenotype CD8+ T cells. 4. Preclinical studies have shown that the toxicity of IL-15 is different from that of IL-2. Compared with IL-2, IL-15 has almost no vascular capillary leakage. These factors make IL-15 a more potential cytokine in tumor immune strategies.
  • IL-15 super agonist N-803 which is a fusion of IL-15 protein N72D mutation combined with IL-15Ra and IgG1Fc co-expression Protein
  • ImmunityBio submitted to the FDA a marketing application for the IL-15 superagonist N-803, which is used in combination with Bacillus Calmette-Guerin (BCG) to treat non-muscle invasive bladder cancer (NMIBC) that does not respond to BCG.
  • BCG Bacillus Calmette-Guerin
  • NMIBC non-muscle invasive bladder cancer
  • Nivolumab PD-1 antibody, Opdivo
  • N-803 PD-1 antibody, Opdivo
  • SHR-1501 IL-15 fusion protein
  • SHR-1316 PD-L1 monoclonal antibody drug
  • cytokines are small molecular weight proteins and do not have the protection mechanism of antibodies in vivo circulation, simple cytokines often have a short half-life, requiring repeated high-dose administration in a short period of time.
  • most clinical research drugs use PEGylation or Fc fusion to increase the half-life of cytokines. Although the half-life is prolonged, it still cannot solve the problem of poor targeting of cytokines.
  • the first purpose of the present invention is to provide a novel trifunctional fusion protein of antigen targeting, anti-CD16A and immune effector cell activation.
  • the antigen-targeting, anti-CD16A and immune effector cell activation trifunctional fusion protein provided by the present invention includes: a CD16A binding region specifically binding to CD16A, a TAA binding region specifically binding to a tumor-associated antigen (TAA), IL-15 and IL- The IL-15/IL-15R ⁇ complex formed by 15R ⁇ binding, and the Fc domain.
  • TAA tumor-associated antigen
  • IL-15 and IL- The IL-15/IL-15R ⁇ complex formed by 15R ⁇ binding, and the Fc domain.
  • antigens include tumor-associated antigens (TAAs).
  • the trifunctional fusion protein provided by the present invention not only targets CD16A and TAA simultaneously, but also fuses IL-15/IL-15R ⁇ complex and Fc domain, which has unique components and forms a unique configuration.
  • the trifunctional fusion protein of the present invention uses IL-15 and IL-15R ⁇ to replace the CL and CH1 domains in one of the antibody structures of the bispecific antibody respectively, through the super high affinity between IL-15 and IL-15R ⁇
  • the IL-15/IL-15R ⁇ structure formed ensures the correct pairing of the light and heavy chains of the bispecific antibody, thereby solving the problem of light chain mismatch of the bispecific antibody.
  • the trifunctional fusion protein CD16A antibody targets NK cells to the tumor site and activates NK cells near the tumor cells.
  • IL-15 and IL-15R ⁇ stimulate the proliferation and activation of immune effector cells such as NK cells and T cells, greatly enhancing the body's immunosuppressive activity against tumors.
  • the CD16A binding region includes an anti-CD16A antibody or an antigen-binding fragment thereof.
  • the CD16A binding region is a Fab fragment or an Fv fragment targeting CD16A.
  • the TAA-binding region includes an anti-TAA antibody or an antigen-binding fragment thereof.
  • the TAA-binding region is a TAA-targeting Fab fragment or Fv fragment.
  • the fusion protein also includes a connecting fragment; the amino acid sequence of the connecting fragment is preferably several GS repeating sequences.
  • the fusion protein comprises several peptide chains, and the IL-15 and the IL-15R ⁇ are respectively located on different peptide chains.
  • the trifunctional fusion protein includes: one TAA binding region.
  • the fusion protein includes: a first monomer and a second monomer; wherein, the first monomer includes: the TAA binding region and the first Fc chain; the second monomer includes : the CD16A binding region, the IL-15/IL-15R ⁇ complex and the second Fc chain; the TAA binding region is the Fab fragment targeting TAA; the CD16A binding region is the Fv targeting CD16A Fragment; or, the first monomer includes: the CD16A binding region and the first Fc chain; the second monomer includes: the TAA binding region, the IL-15/IL-15R ⁇ complex and the second Fc chain; the CD16A binding region is a Fab fragment targeting CD16A; the TAA binding region is an Fv fragment targeting TAA; and, the first Fc chain and the second Fc chain are polymerized to form The Fc domain.
  • the first monomer includes: the TAA binding region and the first Fc chain
  • the second monomer includes : the CD16A binding region, the IL-15/IL-15R ⁇ complex and the
  • the first monomer includes a first peptide chain and a second peptide chain
  • the second monomer includes a third peptide chain and a fourth peptide chain
  • the first peptide chain includes: a TAA-binding antibody can Variable region, antibody constant region
  • the second peptide chain includes: TAA binding antibody variable region, antibody constant region
  • the antibody constant region of the second peptide chain includes the first Fc chain
  • the third peptide chain includes: CD16A binds to antibody variable regions, cytokines and the second Fc chain
  • the fourth peptide chain includes: CD16A binds to antibody variable regions and cytokines
  • TAA of the first peptide chain binds to antibody variable regions and antibody constant regions
  • the TAA of the second peptide chain binds to the antibody variable region and the paired region of the antibody constant region to form the Fab fragment targeting TAA
  • the CD16A of the third peptide chain binds to the antibody variable region and the first The CD16A binding antibody
  • the first monomer includes a first peptide chain and a second peptide chain
  • the second monomer includes a third peptide chain and a fourth peptide chain
  • the first peptide chain includes: CD16A-binding antibody can Variable region, antibody constant region
  • the second peptide chain includes: CD16A binding antibody variable region, antibody constant region
  • the antibody constant region of the second peptide chain includes the first Fc chain
  • the third peptide chain includes: TAA binds antibody variable regions, cytokines and the second Fc chain
  • the fourth peptide chain includes: TAA binds antibody variable regions and cytokines
  • CD16A of the first peptide chain binds antibody variable regions and antibody constant regions
  • the CD16A of the second peptide chain binds to the antibody variable region and the paired region of the antibody constant region to form the Fab fragment targeting CD16A
  • the TAA of the third peptide chain binds to the antibody variable region and the first The TAA binding antibody variable region of the
  • the fusion sequence of the third peptide chain is: antibody variable region-cytokine-second Fc chain, or: cytokine-antibody variable region-second Fc chain.
  • Two Fc chains; from the N-terminus to the C-terminus of the peptide chain, the fusion sequence of the fourth peptide chain is: antibody variable region-cytokines; or: cytokines-antibody variable regions; " ⁇ " indicates a connecting fragment ;
  • the antibody variable region is a CD16A-binding antibody variable region or a TAA-binding antibody variable region.
  • the trifunctional fusion protein includes: two TAA binding regions.
  • the fusion protein includes: a first monomer and a second monomer; the two TAA binding regions are respectively the first TAA binding region and the second TAA binding region; wherein, the first monomer The monomer includes: the first TAA binding region and the first Fc chain; the second monomer includes: the CD16A binding region, the second TAA binding region, the IL-15/IL- 15R ⁇ complex and the second Fc chain; the first TAA binding region is a Fab fragment targeting TAA; the CD16A binding region is an Fv fragment targeting CD16A; the second TAA binding region is targeting TAA Fv fragment; or, the first monomer includes: the first TAA binding region, the CD16A binding region and the first Fc chain; the second monomer includes: the second TAA binding region, The IL-15/IL-15R ⁇ complex and the second Fc chain; the CD16A binding region is an Fv fragment targeting CD16A; the first TAA binding region and the second TAA binding region are an Fv fragment targeting TAA; and, the first Fc chain
  • the first monomer includes a first peptide chain and a second peptide chain
  • the second monomer includes a third peptide chain and a fourth peptide chain
  • the first peptide chain includes: a TAA-binding antibody can Variable region, antibody constant region
  • the second peptide chain includes: TAA binding antibody variable region, antibody constant region
  • the antibody constant region of the second peptide chain includes the first Fc chain
  • the third peptide chain includes: TAA binds to antibody variable regions, CD16A binds to antibody variable regions, cytokines, and the second Fc chain
  • the fourth peptide chain includes: TAA binds to antibody variable regions, CD16A binds to antibody variable regions, and cytokines
  • the TAA of one peptide chain binds to the antibody variable region and the antibody constant region
  • the TAA of the second peptide chain binds to the antibody variable region and the paired region of the antibody constant region to form the first TAA binding region, and the second peptide
  • the fusion sequence of the amino acid fragments of the third peptide chain or the fourth peptide chain includes any of the following, wherein " ⁇ " represents a connecting fragment:
  • CD16A binding antibody variable region ⁇ cytokine ⁇ TAA binding antibody variable region
  • the fusion protein includes: a first monomer and a second monomer; wherein, the first peptide chain includes: a TAA-binding antibody variable region, a CD16A-binding antibody variable region, and an antibody constant region;
  • the second peptide chain includes: TAA binding antibody variable region, CD16A binding antibody variable region, antibody constant region; the antibody constant region of the second peptide chain includes the first Fc chain;
  • the third peptide chain includes: TAA Binding antibody variable region, cytokine and second Fc chain;
  • the fourth peptide chain includes: TAA binding antibody variable region, cytokine; TAA binding antibody variable region of the first peptide chain and the second
  • the TAA binding antibody variable region of the peptide chain is paired to form the first TAA binding region, and the first TAA binding region is an Fv fragment targeting TAA;
  • the CD16A binding antibody variable region of the first peptide chain and The CD16A-binding antibody variable region of the second peptide chain is paired to
  • the fusion sequence of the TAA-binding antibody variable region and the CD16A-binding antibody variable region It is: TAA binding antibody variable region ⁇ CD16A binding antibody variable region, or CD16A binding antibody variable region ⁇ TAA binding antibody variable region; " ⁇ " indicates a connecting fragment; or, in the third peptide chain or the In the fourth peptide chain, from the N-terminal to the C-terminal of the peptide chain, the fusion sequence of the TAA-binding antibody variable region and the cytokine is: TAA-binding antibody variable region-cytokines, or cytokine-TAA-binding Antibody variable regions.
  • the TAA-binding antibody variable region is selected from a TAA-targeting VH domain or VL domain
  • the CD16A-binding antibody variable region is selected from a CD16A-targeting VH domain or VL domain
  • the The cytokine is selected from IL-15 or IL-15R ⁇ ; the antibody constant region includes a CL domain or a CH1 domain.
  • the IL-15 includes: IL-15 and its mutations, truncations and various derivatives that can bind IL-15Ra; the IL-15Ra includes: IL-15Ra and its IL-15-binding Mutation, truncation and various derivatives; preferably, the IL-15 includes but is not limited to any of the following combinations of mutations, and the counting method is counted from the first amino acid of the amino acid sequence of IL-15 1 person;
  • the IL-15/IL-15Ra complex includes, but is not limited to, the mutations shown in any of the following combinations, and the counting method is counted as the first amino acid starting from the first amino acid of the amino acid sequence of IL-15 or IL-15Ra bit;
  • the TAA is selected from CD20, CD19, CD30, CD33, CD38, CD40, CD52, slamf7, GD2, CD24, CD47, CD133, CD217, CD239, CD274, CD276, CEA, Epcam, Trop2, TAG72, MUC1 , MUC16, mesothelin, folr1, CLDN18.2, EGFR, EGFR VIII, C-MET, HER2, FGFR2, FGFR3, PSMA, PSCA, EphA2, ADAM17, 17-A1, NKG2D ligands, MCSP, LGR5, SSEA3, SLC34A2, BCMA , GPNMB, CCR4, VEGFR-2, CD6, Integrin ⁇ 4, PDGFR ⁇ , NeuGcGM3, Integrin ⁇ V ⁇ 3, CD51, CTAA16.88, CD22, ROR1, CSPG4, SS1, or IGFR1.
  • the Fc domain is selected from Human IgG1 Fc, Human IgG2 Fc, Human IgG3 Fc, Human IgG4 Fc or variants thereof, preferably from IgG1 Fc, or Human IgG4 Fc or variants thereof;
  • the Fc domain In the form of an Fc heterodimer; preferably, the Fc heterodimer comprises, but is not limited to, a combination of the following mutations, which are counted according to EU:
  • the Fc domain is selected to eliminate the immune effector function, and preferably includes any of the following mutation methods, and the following mutations are counted according to EU:
  • the first Fc chain does not bind protein A, preferably including the mutation H435R or H435R/Y436F, counted according to EU; the second Fc chain can bind protein A.
  • the CD16A binding region includes a sequence such as the VH domain shown in SEQ ID NO:97 and the VL domain shown in SEQ ID NO:96; or, the sequence of the IL-15 is as shown in SEQ ID NO: 104 or 105; or, the sequence of IL-15Ra is as shown in any one of SEQ ID NO: 106 to 112; preferably, between the VH and VL of the CD16A binding region, and/or the There are at least one pair of disulfide bonds between IL-15 and IL-15Ra.
  • the antigens also include: infectious disease-related antigens, pathogens, and immune function-related antigens.
  • TAA tumor-associated antigen
  • the present invention also provides a nucleic acid molecule encoding the trifunctional fusion protein of antigen targeting, anti-CD16A and immune effector cell activation.
  • the present invention also provides a pharmaceutical composition, which contains the fusion protein with three functions of antigen targeting, anti-CD16A and immune effector cell activation, and a pharmaceutically acceptable carrier.
  • the present invention also provides the application of the fusion protein with three functions of antigen targeting, anti-CD16A and immune effector cell activation in the preparation of medicines for inhibiting or treating cancer, infection and immune regulation diseases.
  • Such cancers include prostate cancer, lung cancer, colon cancer, rectal cancer, bladder cancer, melanoma, kidney cancer, oral cavity cancer, pharyngeal cancer, pancreatic cancer, uterine cancer, thyroid cancer, skin cancer, head and neck cancer, cervical cancer, ovarian cancer or hematological cancers.
  • the present invention also provides a protein composite unit, which includes: the CD16A-binding antibody variable region and cell Factors, CD16A binding antibody variable regions of the fourth peptide chain and cytokines, and several connecting fragments; CD16A binding antibody variable regions of the third peptide chain are fused with the cytokines of the third peptide chain through connecting fragments; The CD16A binding antibody variable region of the fourth peptide chain is fused with the cytokine of the fourth peptide chain through a connecting fragment; the CD16A binding antibody variable region of the third peptide chain and the CD16A of the fourth peptide chain The variable region of the binding antibody is selected from the VH domain or VL domain targeting CD16A, and paired to form an Fv fragment; the cytokine of the third peptide chain and the cytokine of the fourth peptide chain are selected from IL15 or IL15R ⁇ , And combined to form IL-15/IL-15R complex; preferably, there are more than one pair of disulfide bonds
  • the present invention also provides a nucleic acid molecule encoding the complex unit of the protein.
  • the trifunctional fusion protein provided by the present invention includes a CD16A binding region specifically binding to CD16A, a TAA binding region specifically binding to a tumor-associated antigen (TAA), IL-15 and IL-15R ⁇ formed by combining IL-15/IL
  • TAA tumor-associated antigen
  • IL-15 and IL-15R ⁇ formed by combining IL-15/IL
  • the -15R ⁇ complex, as well as the Fc domain not only can simultaneously target CD16A and TAA, but also fuses the IL-15/IL-15R ⁇ complex and the Fc domain, which has unique components and forms a unique configuration.
  • the TAA/CD16A/IL15 trifunctional fusion protein designed in the present invention targets NK cells to tumors by simultaneously binding tumor-associated antigen (TAA) on tumor cells and CD16A on NK cells, and NK cells release perforin, granules enzyme, triggers apoptosis and leads to tumor cell death.
  • TAA tumor-associated antigen
  • the cytokine IL15 amplifies and maintains NK cell function, stimulates immune cell proliferation, and alters the immune microenvironment of tumors.
  • the trifunctional fusion protein of antigen targeting, anti-CD16A and immune effector cell activation constructed by the present invention has IL-15/IL-15R ⁇ activity, can target cytokines to tumor sites, and can specifically expand tumor sites. Increase and activate immune effector cells (NK cells and T cells), increase the number of immune cells and the release of killer cytokines, and more effectively activate the immune response to kill tumor cells.
  • NK cells and T cells immune effector cells
  • one or more pairs of disulfide bonds can be added between VH and VL and between IL-15 and IL-15R ⁇ through amino acid sequence mutations to further enhance the binding activity between the light chain/heavy chain and bind to Fc
  • the heterodimer technology solves the problem of heavy chain mismatch of bispecific antibodies, more effectively overcomes the challenges of light chain and heavy chain mismatch, high by-products, and poor stability in the preparation of bispecific antibodies, and prepares correctly paired multifunctional antibodies. Fusion proteins, meanwhile, shorten the development cycle of multifunctional fusion proteins and reduce production costs.
  • the effector function of the Fc domain can be retained, or the Fc domain in the form of eliminating the immune effector can be used.
  • Fc binding to FcR ⁇ III (CD16A) is rendered incapable of Fc using an Fc domain in an immune effector-eliminating form. If the fusion protein of the present invention retains the effector function of the Fc domain, the corresponding activation effect of immune cells is also observed.
  • Figures 1 to 19 are schematic diagrams of the structural forms of the trifunctional fusion proteins in different embodiments of the present invention, in which Figures 1 to 9 show the trifunctional fusion with a TAA binding region and CD16A binding region ratio of 1:1 Protein; Fig. 10 to Fig. 19 show the trifunctional fusion protein with the ratio of TAA binding region and CD16A binding region in the form of 2:1.
  • Figure 20 and Figure 21 are the results of FACS detection of trifunctional protein binding to HL60 cells.
  • Figure 22, Figure 23, and Figure 24 are the results of FACS detection of CD38/CD16A/IL-15 trifunctional fusion protein binding to Daudi cells.
  • Fig. 25 is a graph showing the results of ELISA detection of trifunctional molecules binding to CS1 protein.
  • Figure 26 to Figure 32 are graphs showing the results of CCK8 detection of TAA/CD16A/IL-15 trifunctional fusion protein on the proliferation of Mo7e cells.
  • Figure 33 to Figure 38 are the results of the ADCC effect mediated by the CD33/CD16A/IL-15 trifunctional fusion protein, wherein the effect-target ratio in Figure 33 and Figure 34 is 10:1, and the effect-target ratio in Figure 35 is 20:1, Figure 36, Figure 37, Figure 38 The effect-to-target ratio is 10:1.
  • Figure 39 to Figure 42 are the results of ADCP mediated by the CD38/CD16A/IL-15 trifunctional fusion protein, wherein the effect-target ratio in Figure 39 is 10:1, and the effect-target ratio in Figure 40 is 5:1, Figure 41 and Figure 41 42 The effect-to-target ratio was 10:1.
  • Figure 43 is a graph showing the results of ADCP mediated by the CD33/CD16A/IL-15 trifunctional fusion protein.
  • fused refers to linking components directly by peptide bonds or via linker fragments, or non-covalently fused by intermolecular interactions or covalently fused by one or more disulfide bonds or chemical cross-links. Within a single peptide chain, fusion refers to direct linking by peptide bonds or linking via linking fragments.
  • Multifunctional fusion protein refers to a protein comprising two or more antigen-binding domains capable of binding two or more different epitopes (e.g., two, three or more different epitopes ), the multifunctional fusion protein can also contain cytokines (such as IL-15, IL-15Ra) and the like.
  • Fusion position refers to the position of the functional region or structural domain in the peptide chain, indicating the connection sequence of the functional fragments on the peptide chain.
  • polypeptide refers to amino acid chains of any length, including proteins and fragments thereof.
  • the present invention discloses a polypeptide as a sequence of amino acid residues. Those sequences are written left to right in amino-terminal to carboxy-terminal orientation.
  • amino acid residue sequences are designated by three-letter or one-letter codes as follows: alanine (Ala,A), arginine (Arg,R), asparagine ((Asn,N) , Aspartic acid (Asp, D), Cysteine (Cys, C), Glutamine (Gln, Q), Glutamic acid (Glu, E), Glycine (Gly, G), Histidine (His, H), isoleucine (I1e, I), leucine (Leu, L), lysine (Lys, K), methionine (Met, M), phenylalanine (Phe , F), proline (Pro,P), serine (Ser,S), threonine (Thr,T), tryptophan (Trp,W), tyrosine (Tyr,Y) and valine (Val,V).
  • peptide chain refers to a molecule of amino acids linearly linked by peptide bonds.
  • variant refers to a polypeptide or polynucleotide that differs from the included amino acids or nucleotides but retains essential properties. Usually the differences between variants or between variants and the parental antibody are limited and the amino acid sequences are very similar overall.
  • the antibody or antibody fragment before mutation is referred to as parent antibody, and the antibody or antibody fragment after mutation is referred to as variant. The variant still has antigen binding activity.
  • antibody refers to an immunoglobulin molecule (immunoglobulin, Ig) comprising at least one antigen-binding site and capable of specifically binding an antigen.
  • antigen is a substance that can induce an immune response in the body and specifically binds to an antibody.
  • the binding of antibody and antigen is mediated by the interaction formed between them, including hydrogen bond, van der Waals force, ionic bond and hydrophobic bond.
  • the region on the surface of an antigen that binds to an antibody is called an "antigenic determinant” or "epitope".
  • each antigen has multiple determinants.
  • antibody referred to in the present invention is understood in its broadest sense and includes monoclonal antibodies (including full-length monoclonal antibodies), polyclonal antibodies, antibody fragments, antibodies comprising at least two different antigen-binding domains Multispecific antibodies (eg, bispecific antibodies).
  • Antibodies also include murine antibodies, humanized antibodies, chimeric antibodies, human antibodies, and antibodies of other origin.
  • the antibodies of the present invention can be derived from any animal, including but not limited to immunoglobulin molecules of humans, non-human primates, mice, rats, cows, horses, chickens, camels, and alpacas. Antibodies may contain additional alterations, such as unnatural amino acids, Fc effector function mutations, and glycosylation site mutations.
  • Antibodies also include post-translationally modified antibodies, fusion proteins comprising antigenic determinants of antibodies, and immunoglobulin molecules comprising any other modification to the antigen recognition site, so long as these antibodies exhibit the desired biological activity.
  • antibodies include immunoglobulin molecules and immunologically active fragments of immunoglobulin molecules, ie, molecules that contain at least one antigen-binding domain.
  • the basic structure of an antibody is a Y-shaped monomer composed of two identical heavy chains (heavy chain, H) and two identical light chains (light chain, L) connected by disulfide bonds. Each chain is composed of 2 to 5 structural domains (also known as functional regions) of about 110 amino acids with similar sequences but different functions.
  • the amino acid sequence of the light chain and the heavy chain near the N-terminus of the antibody molecule changes greatly, and the formed domain is called the variable region (variable region, V region); the relatively constant region near the C-terminal amino acid sequence is called the constant region (constant region) , area C).
  • VH and VL The V regions of the heavy chain and light chain are called VH and VL, respectively, and each of VH and VL has three regions whose amino acid composition and sequence are highly variable, called hypervariable region (HVR); the formation of this region is related to the expression of antigen
  • the complementary spatial conformation is also called complementarity determining region (CDR).
  • the three CDRs of VH are represented by VHCDR1, VHCDR2, and VHCDR3, and the three CDRs of VL are represented by VLCDR1, VLCDR2, and VLCDR3, respectively.
  • a total of 6 CDRs of VH and VL together form the antigen-binding site.
  • the diversity of amino acids in the CDR region is the molecular basis for the specific binding of antibodies to a large number of different antigens.
  • VH and VL each have four framework regions (or framework regions), which are represented by FR1, FR2, FR3, and FR4, respectively.
  • Each VH and VL consists of three CDRs and four FRs, and the sequence from the amino terminal to the carboxyl terminal is: FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4.
  • human immunoglobulins can be divided into 5 classes: IgM, IgG, IgA, IgD, IgE. It can be further divided into different subclasses (isotypes), for example, human IgG can be divided into IgG1, IgG2, IgG3, IgG4; IgA can be divided into IgA1 and IgA2. IgM, IgD, and IgE have not yet been found to have subclasses.
  • light chains can be classified into kappa chains and lambda chains.
  • Antibodies of the invention may be of any class (eg, IgM, IgG, IgA, IgD, IgE) or subclass (eg, IgGl, IgG2, IgG3, IgG4, IgAl, IgA2).
  • class eg, IgM, IgG, IgA, IgD, IgE
  • subclass eg, IgGl, IgG2, IgG3, IgG4, IgAl, IgA2
  • the constant regions of the heavy and light chains are called CH and CL, respectively.
  • the heavy chain constant regions of IgG, IgA, and IgD have three domains, CH1, CH2, and CH3, and the heavy chain constant regions of IgM and IgE have four domains, CH1, CH2, CH3, and CH4.
  • the hinge region (hinge region) is located between CH1 and CH2 and is rich in proline, so it is easy to stretch and bend, and can change the distance between the two arms of the Y shape, which is conducive to the simultaneous binding of the two arms to the antigenic epitope.
  • Fab fragment is a fragment of antigen binding (Fab), which means an antibody fragment composed of VL, VH, CL and CH1 domains, which binds to a single antigenic epitope (monovalent).
  • Fab antigen binding
  • Fab fragment of antigen binding
  • Fv fragment is a monovalent small molecule composed of the L chain and the V region (VH+VL) of the H chain, and is the smallest functional fragment that binds to an antigen.
  • Fc fragment crystallizable, which has no antigen-binding activity and is the interaction between an antibody and an effector molecule or a cell surface Fc receptor (FcR).
  • FcR cell surface Fc receptor
  • the site of action. Fc fragments bind to cells with corresponding Fc receptors on their surface and produce different biological effects.
  • ADCC effect antibody-dependent cell-mediated cytotoxicity
  • the Fab segment of the antibody binds to the antigenic epitope of the virus-infected cell or tumor cell, and its Fc segment interacts with the killer cell (NK FcR binding on the surface of cells, macrophages, etc.) mediates killer cells to directly kill target cells.
  • NK FcR binding on the surface of cells, macrophages, etc.
  • the Fc fragment includes the constant region polypeptides of the antibody except the heavy chain constant region CH1, that is, the two constant region domains CH2 and CH3 at the carboxy-terminal of the heavy chain constant region of human immunoglobulin IgA, IgD, and IgG, and human immunoglobulin IgE and The three constant region domains CH2, CH3 and CH4 at the carboxy-terminal end of the IgM heavy chain constant region.
  • the Fc fragment is usually selected from Human IgG1 Fc, Human IgG2 Fc, Human IgG3 Fc, Human IgG4 Fc or variants thereof, preferably from IgG1 Fc, or Human IgG4 Fc or variants thereof
  • Fc can be composed of two chains.
  • the two chains of the Fc fragment are described herein as the first Fc chain and the second Fc chain.
  • the first Fc chain and the second Fc chain can be mutated respectively, which is not particularly limited in the present invention.
  • Fc fragment can also refer to a single polypeptide chain within the Fc domain.
  • the Fc segment of the antibody can be selected to eliminate the immune effector function, including but not limited to the combination of the following mutations (counted according to EU)
  • a preferred mutation design is a "Knob-in-hole" style mutation design.
  • a “linking segment” refers to one or more amino acid residues that are inserted into an immunoglobulin domain and provide sufficient mobility, necessary to ensure proper folding of the protein and stability of the peptide.
  • the "connecting segment” is preferably (GGGGS)n, where n can be 0, 1, 2, 3, 4, 5 or more. If the connecting fragment sequence is too short, it may affect the folding of the high-level structure of the two proteins, thereby interfering with each other; if the connecting peptide sequence is too long, it will involve the issue of immunogenicity, because the connecting peptide sequence itself is a new antigen.
  • Tumor-associated antigen refers to the antigen molecules present on tumor cells or normal cells, including: embryonic protein, glycoprotein antigen, squamous cell antigen, etc., which are often used in the diagnosis of clinical tumors. Tumor-associated antigens are not unique to tumor cells, and can be synthesized in a small amount by normal cells, but are highly expressed when tumor cells proliferate, so they are called "associated antigens”.
  • Tumor-associated antigens can be, for example, CD20, CD19, CD30, CD33, CD38, CD40, CD52, slamf7, GD2, CD24, CD47, CD133, CD239, CD276, PD-1, CEA, Epcam, Trop2, TAG72, MUC1, MUC16, mesothelin, folr1, CLDN18.2, PDL1, EGFR, EGFR VIII, C-MET, HER2, FGFR2, FGFR3, PSMA, PSCA, EphA2, ADAM17, 17-A1, NKG2D ligands, MCSP, LGR5, SSEA3, SLC34A2, BCMA, GPNMB or Glypican-3.
  • vector means a polynucleotide molecule capable of transporting another polynucleotide to which it has been linked.
  • plasmid refers to a circular double-stranded DNA loop into which additional DNA segments can be ligated.
  • viral vector in which additional DNA segments can be ligated into the viral genome.
  • Certain vectors are capable of autonomous replication in the host cells into which they are introduced (eg, bacterial vectors and episomal mammalian vectors with a bacterial origin of replication). Other vectors (eg, non-episomal mammalian vectors) can integrate into the genome of the host cell after introduction into the host cell, thereby replicating along with the host genome.
  • certain vectors are capable of directing the expression of genes to which they are operably linked.
  • expression vectors useful in recombinant DNA techniques are usually in the form of plasmids.
  • the present invention can provide a vector comprising a nucleic acid fragment capable of encoding a trifunctional fusion protein.
  • IL-15 may be mutants or fragments thereof.
  • the "IL-15” of the present invention can be any IL-15 or a mutant capable of binding IL-15R ⁇ , such as human IL-15 or non-human mammal or non-mammal IL-15. Exemplary non-human mammals such as pigs, rabbits, monkeys, orangutans, mice, etc., non-mammals such as chickens, etc.; human IL-15 is preferred.
  • mutant capable of binding IL-15R ⁇ refers to an increase or decrease in the affinity between IL-15 and its receptor obtained by one or more amino acid substitutions, additions or deletion mutations, or an increase in the activity of stimulating T cells or NK cells or Reduced mutant molecules.
  • the "IL-15R ⁇ ” mentioned in the present invention can be IL-15R ⁇ of any species or a mutant capable of binding IL-15R ⁇ , such as human IL-15R ⁇ or non-human mammalian IL-15R ⁇ or non-mammalian IL-15R ⁇ .
  • exemplary non-human mammals such as pigs, rabbits, monkeys, orangutans, mice, etc., non-mammals such as chickens, etc.
  • IL-15R ⁇ more preferably human IL-15R ⁇ extracellular domain fragment, referred to as IL-15R ⁇ ECD (see database UniProtKB, accession number Q13261, 31-205aa).
  • mutant that can bind IL-15R ⁇ refers to a functional mutant that has the ability to bind to its ligand molecule such as IL-15 formed by one or more amino acid deletions, insertions or substitution mutations on IL-15R ⁇ , preferably human
  • the IL-15R ⁇ molecule is more preferably a shortened form of the human IL-15R ⁇ ectodomain fragment, that is, a molecule with human IL-15 receptor ⁇ activity obtained from the C-terminus of the ectodomain fragment through one or more amino acid deletion mutations, preferably Deletion mutant forms of 65-178 amino acids are retained, such as IL-15R ⁇ .
  • IL-15 protein by itself is less stable than when complexed with IL-15R ⁇ protein.
  • the IL-15R ⁇ protein contains a "sushi domain", which is the shortest region of the receptor retaining IL-15 binding activity, or a domain in the extracellular region capable of retaining more than 90% of the binding activity.
  • CS1 (also known as CD319, SLAMF7) is a member of the signaling lymphocyte activation molecule family 7, and is a surface receptor protein that regulates the immune function of NK cells.
  • CS1 is highly expressed in multiple myeloma (MM) cell lines but not found in healthy tissues, primary tumor tissues or hematological and non-hematological cancer cell lines, making it an attractive target for the treatment of this disease.
  • MM myeloma
  • CD33 is a single-pass transmembrane glycoprotein of 67 kD and is a member of the sialic acid-binding immunoglobulin-like lectins (Siglecs) family. Although its exact biological function is unknown, in normal individuals it is primarily considered to be a myeloid differentiation antigen, with low expression in myeloid progenitors, neutrophils, and macrophages, and in Highly expressed in circulating monocytes and dendritic cells. Importantly, CD33 has been detected in blasts and leukemic stem cells in 85% to 90% of patients with acute myeloid leukemia (AML).
  • AML acute myeloid leukemia
  • CD33 expression is restricted to hematopoietic cells (Paul, Taylor, Stansbury, & McVicar, 2000; Ulyanova, Blasioli, Woodford-Thomas, & Thomas, 1999), but is absent on normal hematopoietic stem cells (Andrews, Torok -Storb and Bernstein, 1983 Griffin, Linch, Sabbath, Larcom, and Schlossman, 1984; Jilani et al., 2002).
  • CD38 antigen is a type II transmembrane glycoprotein with a size of 46kDa.
  • the ligand of CD38 is CD31, also known as PECAM-1, which is a member of the Ig gene superfamily.
  • CD31 is also expressed on lymphoid cells (theca B cells and plasma cells), lung (alveolar ducts, alveoli and lymphatic vessels) and kidney (glomerular cells).
  • CD38 interacts with the ligand CD31 and plays an important role in regulating cell migration, receptor-mediated adhesion, and signal transduction.
  • CD38 protein is also a bifunctional extracellular enzyme, which has both cyclase and hydrolase activities and is involved in nucleotide metabolism.
  • CD38 uses NAD+ as a substrate to form cyclic ADP-ribose (cADPR) and ADPR, and these nucleotide metabolites are potent second messengers that regulate the mobilization of calcium ions in the cytoplasm and activate signaling pathways that control various biological processes , such as lymphocyte proliferation, pancreatic B cell secretion of insulin and so on. It has also been shown that CD38-dependent adenosine production also plays a key role in immune suppression mediated by natural killer (NK) cells. In general, CD38 is expressed at low levels on normal lymphoid and myeloid cells, as well as non-hematopoietic tissues, but is widely expressed on cells of hematopoietic origin, including committed stem cells.
  • cADPR cyclic ADP-ribose
  • ADPR cyclic ADP-ribose
  • CD38-dependent adenosine production also plays a key role in immune suppression mediated by natural killer (NK) cells.
  • NK natural killer
  • CD38 is expressed in B cells, and CD38 expression levels are particularly high in plasma cells (also called effector B cells).
  • CD38 expression has been linked to a variety of diseases, including AIDS, autoimmune diseases (such as systemic lupus erythematosus), type 2 diabetes, osteoporosis and cancer. Studies have found that CD38 is highly expressed in a large number of malignant blood cancers, especially in multiple myeloma and other cancers, which makes CD38 a target for the development of multiple myeloma therapeutic antibody drugs.
  • ADCC or "antibody-dependent cell-mediated cytotoxicity” means a cell-mediated response in which non-specific cytotoxic cells expressing Fc ⁇ Rs recognize bound antibodies on target cells and subsequently cause lysis of the target cells.
  • ADCC is associated with binding of Fc ⁇ RIIIa; increased binding to Fc ⁇ RIIIa results in an increase in ADCC activity.
  • ADCP or antibody-dependent cell-mediated phagocytosis means a cell-mediated response in which non-specific cytotoxic cells expressing Fc ⁇ Rs recognize bound antibodies on target cells and subsequently cause phagocytosis of the target cells.
  • Percent (%) amino acid sequence identity with respect to protein sequences is defined as, after aligning the sequences and introducing gaps where necessary to achieve the maximum percent sequence identity, and disregarding any conservative substitutions as part of the sequence identity, candidate The percentage of amino acid residues in a sequence that are identical to those in a specific (parental) sequence. In some embodiments, two or more amino acid sequences are at least 80%, 85%, or 90% identical. In some embodiments, two or more amino acid sequences are at least 95%, 97%, 98%, 99%, or even 100% identical.
  • first and second are used for descriptive purposes only, and do not indicate or imply their degree of importance.
  • the antigen-targeting, anti-CD16A and immune effector cell activation trifunctional fusion protein of the present invention includes: a CD16A binding region specifically binding to CD16A, a TAA binding region specifically binding to a tumor-associated antigen (TAA), IL-15 and IL-15R ⁇ Combined with the formed IL-15/IL-15R ⁇ complex, and the Fc domain.
  • TAA/CD16A/IL-15 trifunctional fusion protein of the present invention exerts a therapeutic effect mainly by simultaneously combining tumor-associated antigen (TAA) expressed on tumor cells and CD16A on NK cells, and cross-linking these two cells to form an immune system. Synapse, promote NK cells to kill tumor cells, while IL-15 amplifies and maintains NK cell function.
  • the TAA binding region and the CD16A binding region of the fusion protein of the present invention are in a 1:1 format, and in other embodiments, a 2:1 format.
  • the structure of the 1:1 trifunctional fusion protein can be referred to Figure 1 to Figure 9.
  • the fusion protein is formed by fusion of four peptide chains, the first peptide chain and the second peptide chain form the first monomer (the left part of the figure), the third peptide chain and the fourth peptide chain form the second monomer (the right part of the figure part).
  • the first peptide chain includes: the light chain formed by the fusion of the VL domain and the CL domain
  • the second peptide chain includes: the heavy chain formed by the fusion of the VH domain, the CH1 domain and the first Fc chain; the first peptide chain
  • the VL domain, the CL domain, and the VH domain and the CH1 domain of the second peptide chain are paired to form a Fab fragment.
  • the third peptide chain includes: antibody variable region, cytokine and the second Fc chain; the fourth peptide chain includes: antibody variable region, cytokine.
  • the antibody variable region of the third peptide chain is paired with the antibody variable region of the fourth peptide chain to form an Fv fragment, and the cytokine of the third peptide chain and the cytokine of the fourth peptide chain are combined to form the IL- 15/IL-15R ⁇ complex.
  • the Fab fragment in the first monomer targets TAA to realize the function of TAA Antibody in the figure.
  • the antibody variable region paired to form the Fv fragment is selected from the VH domain and the VL domain, for example, the antibody variable region in the third peptide chain is selected to target the VH domain of CD16A, and the fourth peptide The antibody variable region of the chain is selected to target the VL domain of CD16A, and VH and VL are paired to form an Fv fragment targeting CD16A, realizing the function of Anti-CD16A Antibody in the figure.
  • variable region of the antibody in the third peptide chain is selected to target the VL domain of CD16A
  • variable region of the antibody in the fourth peptide chain is selected to target the VH domain of CD16A.
  • VH(L) in the figure means to select VH or VL.
  • the numbers in "VH(L)1", “VL(H)1", “VH2", and “VL2" in the figure are for descriptive purposes only, and represent antibody variable regions targeting different antigens.
  • VH(L)1 means that VH1 or VL1 can be selected.
  • VH1 is selected for the antibody variable region of the third peptide chain
  • VL1 should be selected for the antibody variable region of the fourth peptide chain, so that they can be paired to form Fv fragments.
  • the cytokines in the third peptide chain and the fourth peptide chain are selected from IL-15 and IL-15R ⁇ , forming IL-15/IL-15R ⁇ complex (IL-15/IL-15R ⁇ complex).
  • IL-15 is selected as the cytokine in the third peptide chain
  • IL-15R ⁇ is selected as the cytokine in the fourth peptide chain.
  • IL-15R ⁇ is selected for the third peptide chain
  • IL-15 is selected for the fourth peptide chain.
  • the fusion order of antibody variable regions (VH or VL) and cytokines is not limited.
  • the fusion sequence of the third peptide chain is: antibody variable region ⁇ cytokine ⁇ second Fc chain
  • the fourth peptide chain is: antibody variable region-cytokines
  • " ⁇ " indicates the linking fragment.
  • the difference between the fusion protein shown in Figure 2 and Figure 1 is that, from the N-terminal to the C-terminal of the peptide chain, the fusion sequence of the fourth peptide chain is: cytokine-antibody variable region.
  • the spherical shape and the crescent shape in Figures 1 to 8 represent different cytokines. It is assumed that the spherical shape represents IL-15, and the crescent shape represents IL-15Ra. From the N-terminus of the peptide chain to the C-terminus, the possible combinations of the third peptide chain and the fourth peptide chain of the fusion protein shown in Figures 1 to 8 are listed as follows:
  • the Fab fragment in the first monomer targets CD16A, realizing the function of Anti-CD16A Antibody in the figure.
  • the Fv fragment targets TAA to realize the function of Anti-TAA Antibody in the figure.
  • the fusion protein shown in FIG. 9 can also have various possible combinations of the third peptide chain and the fourth peptide chain listed in Table 1.
  • the structure of the trifunctional fusion protein with TAA binding region and CD16A binding region in the form of 2:1 can refer to Fig. 10 to Fig. 19 .
  • the fusion protein is formed by fusion of four peptide chains, the first peptide chain and the second peptide chain form the first monomer (the left part of the figure), the third peptide chain and the fourth peptide chain form the second monomer (the right part of the figure part).
  • the first monomer includes a TAA binding region (TAA antibody) and an Fc chain
  • the second monomer includes a CD16A binding region (CD16A antibody), a TAA binding region ( TAA antibody), IL-15/IL-15R ⁇ complex (IL15/IL15Ra complex) and an Fc chain, and two FC chains aggregate to form an Fc domain (Fc Heterodimer).
  • the two TAA binding regions are respectively the first TAA binding region and the second TAA binding region.
  • the first peptide chain of the trifunctional fusion protein in 2:1 format includes: TAA binding antibody variable region (such as anti-TAA VL domain), antibody constant region (such as CL structure domain);
  • the second peptide chain includes: TAA binding antibody variable region (such as anti-TAA VH domain), antibody constant region (such as CH1 domain and first Fc chain);
  • the third peptide chain includes: TAA binding antibody can Variable region (e.g. VH domain of anti-TAA), CD16A binding antibody variable region (e.g. VL domain of anti-CD16A), cytokine (e.g.
  • fourth peptide chain includes: CD16A binding Antibody variable regions (eg VH domain against CD16A), TAA binding antibody variable regions (eg VL domain against TAA), cytokines (eg IL-15Ra).
  • VL, CL of the first peptide chain, and VH, CH1 of the second peptide chain are paired to form the first TAA binding region, and the first TAA binding region is a Fab fragment targeting TAA.
  • the CD16A of the third peptide chain The CD16A-binding antibody variable region that binds to the antibody variable region and the fourth peptide chain is paired to form a CD16A-binding region, and the CD16A-binding region is an Fv fragment targeting CD16A (the second TAA-binding region and CD16A-binding region form a diabody antibody fragment) ;
  • the cytokine of the third peptide chain and the cytokine of the fourth peptide chain combine to form IL-15/IL-15R ⁇ complex.
  • FIG. 10 Three functional fusion proteins (forms 1A to 1D) shown in Figure 10 and Figure 11, which target the same target and have the same domains, the difference lies in the fusion order of the domains in the third peptide chain and the fourth peptide chain different.
  • the fusion sequence of the domains of the third peptide chain from the N-terminal to the C-terminal is: VH (anti TAA) ⁇ VL (anti CD16A) ⁇ IL-15Ra ⁇ second Fc chain;
  • the fusion sequence of domains of the fourth peptide chain from N-terminal to C-terminal is: VH (anti CD16A) ⁇ VL (anti TAA) ⁇ IL-15.
  • the fusion sequence of the domain of the third peptide chain from the N-terminus to the C-terminus is: VH (anti CD16A) ⁇ VL (anti TAA) ⁇ IL-15Ra ⁇ the second Fc chain;
  • the fusion sequence of the domains of the tetrapeptide chain from the N-terminal to the C-terminal is: VH (anti TAA) ⁇ VL (anti CD16A) ⁇ IL-15.
  • the trifunctional fusion protein shown as format 2A and 2B the cytokine is flanked by antibody variable regions.
  • the trifunctional fusion protein shown in the form 3A and the form 3B the cytokine is fused at the terminal side of the peptide chain.
  • the first monomer includes a CD16A binding region, a TAA binding region and an Fc chain
  • the second monomer includes a TAA binding region, IL-15/IL-15R ⁇ complex and an Fc chain
  • the two FC chains aggregate to form the Fc domain.
  • the trifunctional fusion protein shown in form 4A to form 4D has different fusion sequences of the antibody variable regions of the first peptide chain and the second peptide chain, and the cytokines are fused to the antibody variable regions. between the zone and the FC chain.
  • the trifunctional fusion proteins shown in Format 5A to 5D have cytokines fused to the end.
  • the three-functional fusion protein shown in form 6A to form 6D, in its first monomer, is similar to the DVD-Ig double antibody, and another is inserted at the N-terminus of the antibody light chain and heavy chain respectively.
  • Antibody VL and VH domains For example, in the trifunctional fusion protein shown in Form 6A, the fusion sequence of each structural domain of the first peptide chain is: VL (anti TAA) ⁇ VL (anti CD16A) ⁇ CL; the fusion sequence of the second peptide chain is; VH ( anti TAA) ⁇ VH (anti CD16A) ⁇ CH1 ⁇ Fc.
  • the cytokines can be fused between the variable region of the antibody and the second Fc chain, or at the end side.
  • the present invention does not limit the fusion sequence of the domains in the fusion protein, and those skilled in the art can make other changes except for the examples listed above.
  • the complex unit with innovative structural protein provided by the present invention can refer to the upper part of the second monomer of the fusion protein shown in Figure 1, that is, the region where the Fv fragment of anti-CD16A is fused with the IL-15/IL-15R ⁇ complex.
  • the composite unit includes: two antibody variable regions (VH and VL of anti-CD16A), two cytokines (IL-15, IL-15Ra), and several linking fragments.
  • An antibody variable domain is fused to a cytokine via a linker fragment. Two antibody variable regions pair to form Fv fragments, and two cytokines combine to form IL-15/IL-15R complex.
  • a disulfide bond can be set between VH and VL, and no disulfide bond can be set between IL15 and IL15R ⁇ ; a disulfide bond can also be set between IL15 and IL15R ⁇ , and no disulfide bond can be set between VH and VL; or, in There are disulfide bonds between VH and VL, and between IL15 and IL15R ⁇ .
  • the present invention can use IL-15 and IL-15Ra to replace the CL and CH1 domains in one of the antibody structures respectively, to solve the dual
  • the light chain mismatch problem of specific antibodies can be solved by FC heterodimer form to solve the heavy chain mismatch problem.
  • the FC terminus of the Fab is mutated so that it cannot bind Protein A. Purification The bispecific targeting antibody is purified by two steps of protein A affinity chromatography combined with the FC end and CH1-XL affinity chromatography combined with the CH1 domain.
  • Example 1 Obtaining TAA/CD16A/IL-15 trifunctional fusion protein, molecular cloning, transient expression, and protein purification
  • TAA was selected from CD33, CD38, and CS1 respectively.
  • Protein expression and sequence numbers are shown in the table below.
  • the three-function fusion protein constructed in Table 2 has a TAA-binding region and CD16A-binding region in a 1:1 format; the three-function fusion protein constructed in Table 3, the fusion protein indicated by the double underlined protein number is in a 1:1 format, and the rest are 2:1 format.
  • Table 2 and Table 3 also provide structural descriptions. Taking QP743745 as an example, it can be seen from the structural description that it includes four peptide chains, and the fusion sequences of the four peptide chains are:
  • antiCD33.VH ⁇ CH1 ⁇ Fc using hIgG1, Hole mutation, and another mutation site H435R.
  • sequence of SEQ ID NO:01 is as follows:
  • sequence indicated by the dotted line is the VL of antiCD16A, and the sequence indicated by the wavy line is IL-15.
  • sequence of SEQ ID NO:02 is as follows:
  • the sequence indicated by the dotted line is the VH of antiCD16A
  • the sequence indicated by the wavy line is IL-15Ra
  • the double underline is Fc (Knob mutation).
  • sequence of SEQ ID NO:03 is as follows:
  • the part other than the underline is the light chain sequence of antiCD33, and the sequence indicated by the dotted line is VL.
  • sequence of SEQ ID NO:04 is as follows:
  • the part other than the underline is the heavy chain sequence of antiCD33, and the sequence indicated by the dotted line is VH.
  • the following sequences are also provided:
  • IL-15 or IL-15Ra can be used to construct the fusion protein of the present invention.
  • control antibodies antiCD16a antibody, antiCD33 antibody, Elotuzumab, Daratumumab, TAA/CD16A double antibody were designed and constructed, and CD33/CD16A/IL-15 control molecule GTB-3550 and other molecules were constructed according to the patent document US20200148737A1.
  • Example 2 FACS detection of CD33/CD16A/IL-15 trifunctional fusion protein binding to HL60 cells naturally expressing CD33
  • HL60 cells were cultured in a 5% CO2 incubator at 37°C, digested with trypsin to collect cells, seeded 100,000 cells per well in a 96-well plate, blocked on ice with 2% FBS/PBS for 1 hour, and incubated with three functions at different concentrations Protein and control protein, 1h on ice, washed 3 times with PBS, incubated with PE-anti human FC (1:200) diluted, washed 3 times with PBS, resuspended in 200 microliters of PBS, read the average fluorescence value by FACS, using graphpad prism software Analyze the results.
  • CD33/CD16A/IL-15 trifunctional fusion protein QP743745 (FC wild type), QP43394340 (FC performs L234A/L235A mutation elimination function), QP42914285 (FC performs L234A/L235A mutation elimination function), CD33/ CD16A bispecific antibody QP4115777778 (FC wild-type), CD33/CD16A bispecific antibody QP411543674368 (FC performs L234A/L235A mutation elimination function) and CD33 antibody IgG1wt subtype QP41154116 all bind to HL60 cells that naturally express CD33.
  • CD33 antibody IgG1wt subtype QP41154116 and CD33/CD16A/IL-15 trifunctional fusion protein both bind to HL60 cells that naturally express CD33.
  • Example 3 FACS detection of CD38/CD16A/IL-15 trifunctional fusion protein binding to Daudi cells naturally expressing CD38
  • Daudi cells were cultured in a 5% CO2 incubator at 37°C, digested with trypsin to collect cells, seeded 100,000 cells per well in a 96-well plate, blocked on ice with 2% FBS/PBS for 1 hour, and incubated with three functions at different concentrations Protein and control protein, 1h on ice, washed 3 times with PBS, incubated with PE-anti human FC (1:200) diluted, washed 3 times with PBS, resuspended in 200 microliters of PBS, read the average fluorescence value by FACS, using graphpad prism software Analyze the results.
  • CD38 antibody IgG1wt subtype QP34503451 and CD38/CD16A/IL-15 trifunctional fusion protein QP43394341 all bind to Daudi cells naturally expressing CD38 in a concentration-dependent manner.
  • CD38 antibody IgG1wt subtype QP34503451 and CD38/CS1/CD16A/IL-15 multifunctional fusion protein all bind to Daudi cells naturally expressing CD38 in a concentration-dependent manner.
  • Example 4 ELISA detection of CS1/CD16A/IL-15 trifunctional fusion protein binding to CS1 activity
  • Detection reagents milk (BD, 232100), PBS (Sangon, B548117-0500); HRP-anti human IgG (H+L) (jackson, 109-035-088); TMB (Luoyang Baiaotong Experimental Material Center, C060201); Elisa plate (costa, 9018) 1 ⁇ PBS buffer: Weigh 8.00g of NaCl, 0.20g of KCl, 2.9g of Na2HPO4 12H20, 0.2g of KH2PO4 into 800mL ddH2O and dissolve them in 800mL ddH2O. pH to 7.4, high temperature sterilization for later use.
  • Blocking solution Weigh 5g of milk into PBS, and the blocking solution must be prepared and used immediately.
  • Stop solution (1mol/LH2SO4) Take 109mL 98% concentrated H2SO4 and slowly add it dropwise to 2000mL ddH2O. TMB was developed at 37°C for 10 minutes, placed in a shaker (120 rpm), 100 ⁇ l/well.
  • Add substrate chromogenic solution Add substrate chromogenic solution TMB at 100 ⁇ L/well, place in a shaker, 200 rpm, 35°C, dark for 10 minutes. Termination: After the color development is completed, quickly add the stop solution at 100 ⁇ L/well to terminate the reaction. Detection: Measure the OD value of A450nm on the microplate reader, and use graphpad prism software to analyze the results.
  • Embodiment 5 Mo7e cell proliferation experiment
  • Mo7e human giant cell leukemia cell line
  • IL-15R ⁇ cytokine growth-dependent cells. It has been shown that resting NK and naive T cells express the intermediate-affinity IL-15R ⁇ phenotype, and the results of cytokine IL-15/IL-15Ra on the proliferation of Mo7e (IL-15R ⁇ ) cells are comparable to those on unstimulated PBMC Concordant (Mol Cancer Ther; 11(6) June 2012).
  • the present invention uses the Mo7e cell proliferation assay to evaluate the activity of the multifunctional fusion protein IL-15. The method and results are as follows:
  • Mo7e cells human giant cell leukemia cell line
  • CCK-8 Cell Resource Center
  • recombinant Human GM-CSF was purchased from perprotech, Cat. No. 300-03
  • human IgG was purchased from Sigma, Cat. No. I4506; other antibodies were prepared in-house.
  • Mo7e cells are cultured in RPMI1640 containing 10% FBS, 2mM L-glutamine and 8ng/ml GM-CSF in a 5% CO2 incubator at 37°C; collect Mo7e cells, centrifuge at 800rpm for 5 minutes and discard the supernatant , the cells were washed twice with RPMI1640 medium without GM-CSF; the cells were resuspended and counted with RPMI1640 medium without GM-CSF, and 2 ⁇ 104 cells were seeded in 96-well plates in 80 ⁇ l per well.
  • Cultivate in a 5% CO2 incubator at 37°C for 1 hour dilute each medicinal medium to be tested by a 4-fold gradient, mix 20 ⁇ l of each well with the cell suspension, and culture in a 5% CO2 incubator at 37°C for 3 days; Add 10 ⁇ l of CCK-8 reagent to each well of the 96-well plate to be tested, and incubate in a 5% CO2 incubator at 37°C for 4 hours; take out the 96-well plate, and detect the absorbance at a wavelength of 450 nm in a microplate reader.
  • Figure 26, Figure 27, and Figure 28 show that CD33/CD16A/IL-15, CD38/CD16A/IL-15, and CS1/CD16A/IL-15 three-functional fusion protein can all promote the proliferation of MO7E cells, proving that the three functions of the present invention
  • the protein in the molecular form of the functional fusion protein all has the biological activity of IL-15.
  • Example 6 ADCC effect mediated by CD33/CD16A/IL-15 trifunctional fusion protein
  • PBMC peripheral blood mononuclear cells
  • HL60 cells were purchased from the Cell Bank of the Chinese Academy of Sciences
  • Cytotox96 non-radioactive cytotoxicity assay kit was purchased from Promega (G1780).
  • PBMC PBMC
  • Prepare target cells HL60 is digested with trypsin, 1000rpm for 5min. After washing twice with PBS, spread 96-well plates, 20,000 per well, 50 ⁇ l per well, and incubate at 37 degrees with 5% CO2 for 2 hours.
  • Prepare the antibody Dilute the antibody to 8 concentrations in a gradient with culture medium (RPMI1640 containing 10% low-IgG FBS). Add 50 ⁇ l of the above-diluted antibodies of each concentration to each well, and incubate at 37 degrees for 15 minutes.
  • LDH detection For the maximum release group and volume correction group, add 10 ⁇ l of lysate 45 minutes in advance, and continue to culture in the incubator.
  • Figure 33 and Figure 34 show the results of an effect-to-target ratio of 10:1, and Figure 35 shows the results of an effect-to-target ratio of 20:1.
  • the results showed that CD33 antibody IgG1wt subtype QP41154116 caused NK cells to kill HL60 cells naturally expressing CD33 in a concentration-dependent manner, CD33/CD16A/IL-15 trifunctional fusion protein QP743745 (FC wild type), QP43394340 (FC with L234A/L235A mutation Elimination function), QP42914285 (FC performs L234A/L235A mutation elimination function), CD33/CD16A bispecific antibody QP4115777778 (FC wild type), CD33/CD16A bispecific antibody QP411543674368 (FC performs L234A/L235A mutation elimination function) induced NK cell killing HL60 cells were superior to CD33/CD16A/IL-15 trifunctional fusion protein control molecule GT-3550 (QP877) and CD33 antibody IgG1wt subtype
  • Figure 36, Figure 37, and Figure 38 show the results of an effect-to-target ratio of 10:1.
  • the results showed that CD33 antibody IgG1wt subtype QP41154116 caused NK cells to kill HL60 cells that naturally express CD33 in a concentration-dependent manner, and CD33/CD16A/IL-15 trifunctional fusion protein (FC performs L234A/L235A mutation elimination function) caused NK cells to kill HL60
  • the cells were superior to CD33/CD16A/IL-15 trifunctional fusion protein control molecule GT-3550 (QP877) and CD33 antibody IgG1wt subtype QP41154116.
  • CD16A monoclonal antibody QP43354336 and IL-15/IL-15Ra-FC fusion protein QP33123313 had no ADCC effect.
  • Example 7 ADCC effect mediated by CD38/CD16A/IL-15 trifunctional fusion protein
  • PBMC peripheral blood mononuclear cells
  • Daudi cells were purchased from the Cell Bank of the Chinese Academy of Sciences
  • Cytotox96 non-radioactive cytotoxicity assay kit was purchased from Promega (G1780).
  • PBMC peripheral blood mononuclear cells
  • Prepare target cells Daudi cells are digested with trypsin, 1000rpm for 5min. After washing twice with PBS, spread 96-well plates, 20,000 per well, 50 ⁇ l per well, and incubate at 37 degrees with 5% CO2 for 2 hours.
  • Prepare the antibody Dilute the antibody to 8 concentrations in a gradient with culture medium (RPMI1640 containing 10% low-IgG FBS). Add 50 ⁇ l of the above-diluted antibodies of each concentration to each well, and incubate at 37 degrees for 15 minutes.
  • LDH detection For the maximum release group and volume correction group, add 10 ⁇ l of lysate 45 minutes in advance, and continue to culture in the incubator.
  • Figure 39 shows the results of the effect-to-target ratio of 10:1
  • Figure 40 shows the results of the effect-to-target ratio of 5:1, as shown in the figure: at different effect-to-target ratios, the CD38 antibody IgG1wt subtype QP34503451 caused NK cell killing in a concentration-dependent manner Daudi cells that naturally express CD38
  • CD38/CD16A/IL-15 trifunctional fusion protein QP43394341 FC performs L234A/L235A mutation elimination function
  • CD16A monoclonal antibody QP43354336 and IL-15/IL-15Ra-FC fusion protein QP33123313 had no ADCC effect.
  • Figure 41 and Figure 42 show the results of the effect-to-target ratio of 10:1: CD38 antibody IgG1wt subtype QP34503451 causes NK cells to kill Daudi cells naturally expressing CD38 in a concentration-dependent manner, CD38/CD16A/IL-15 trifunctional fusion protein (FC performs L234A/L235A mutation elimination function) to cause NK cells to kill Daudi cells better than CD38 antibody IgG1wt subtype QP34503451.
  • CD16A monoclonal antibody QP43354336 and IL-15/IL-15Ra-FC fusion protein QP33123313 had no ADCC effect.
  • Example 8 ADCP mediated by CD33/CD16A/IL-15 trifunctional fusion protein
  • PBMC peripheral blood mononuclear cells
  • HL60 cells were labeled with green fluorescent CFSE
  • HL60 cells and macrophages were planted in a 96-well plate at a ratio of 2:1, and then different concentrations of proteins to be detected were added. After incubating at 37°C for 2 hours, the reaction was terminated, and the APC anti-human CD11b antibody was incubated again, and the percentage of APC/FITC double-positive cells under each concentration of antibody was read by FACS, which was the percentage of macrophages undergoing phagocytosis.
  • CD33/CD16A/IL-15 trifunctional fusion protein QP743745 FC wild type
  • QP43394340 FC carries out the function of eliminating L234A/L235A mutation

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Abstract

公开了抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，其包括：特异性结合CD16A的CD16A结合区、特异性结合肿瘤相关抗原(TAA)的TAA结合区、IL-15和IL-15Rα结合形成的IL-15/IL-15Rα复合物、以及Fc结构域。设计的肿瘤靶向先天免疫细胞激活分子，即抗TAA、抗CD16A和细胞因子IL15的三功能融合蛋白，通过同时结合肿瘤细胞上的肿瘤相关抗原(TAA)和NK细胞上的CD16A，将NK细胞靶向肿瘤，NK细胞释放穿孔素、颗粒酶，引发细胞凋亡并导致肿瘤细胞死亡。细胞因子IL15扩增并维持NK细胞功能，刺激免疫细胞增殖，改变肿瘤的免疫微环境。

Description

抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白及其应用 技术领域
本发明涉及生物医药技术领域，具体涉及抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白及其应用。
背景技术
自然杀伤细胞(NK细胞)是一种天然免疫细胞，能够非常有效地破坏应激细胞，如病毒感染或肿瘤转化细胞。NK细胞具有不受MHC限制的细胞毒性、产生细胞因子和免疫记忆等功能，使其成为免疫反应系统中的关键角色。抗体依赖性细胞介导的细胞毒性(ADCC)是一种有效的细胞毒性机制，主要通过自然杀伤(NK)细胞介导。通过CD16a的ADCC作用是NK细胞抗肿瘤效应的主要机制之一。当特异性抗体结合到靶向肿瘤细胞膜上以后，免疫细胞通过该反应诱导细胞死亡。
抗体和免疫细胞的相互作用通过Fc受体(FcR)家族发生。在人类中，IgG的FcR家族(FcγR)由6个受体组成：FcγRI/CD64、FcγRIIa/CD32a、FcγRIIb/CD32b、FcγRIIc/CD32c、FcγRIIIa/CD16a和FcγRIIIb/CD16b，其中CD16a主要触发NK细胞介导的ADCC。通常情况下，ADCC效应主要通过结合FcγRIII(CD16)的抗体激活NK细胞。人类NK细胞分为两个主要亚群：CD56bright和CD56dim。CD56bright NK细胞是强有力的细胞因子产生者，但缺乏CD16a；而CD56dim具有高度的细胞毒性，表达CD16a。当通过CD16a识别IgG调理的靶点时，NK细胞就会释放不同的细胞毒性分子，从而引发靶细胞的死亡。这种机制依赖于免疫突触的形成和含有穿孔素和颗粒酶的溶解颗粒的脱颗粒。除了脱颗粒外，NK细胞还可以通过将靶死亡受体(如DR4、DR5或Fas)与其死亡受体配体(如FasL和TRAIL)结合来清除靶细胞。
CD16a是一种跨膜受体，具有短的C-ter胞质尾，并具有两个细胞外Ig样结构域。CD16a与IgG的CH2以1:1的方式相互作用，其中CH2上的N297位的N-聚糖链在这种相互作用中也起着关键作用。CD16a在其细胞质尾部没有ITAM结构域，因此需要两条含有ITAM结构域的细胞内链串联的帮助，CD3ζ和Fc∈RIγ。CD16a结合后，属于Src家族的激酶Lck被激活，并磷酸化CD3ζ和/或Fc∈RIγ的ITAM结构域。磷酸化的ITAM允许来自Syk家族的激酶招募和磷酸化，例如Syk和ZAP-70，它们反过来负责后续的信号传导。在它们的底物中，PI3K是高度相关的，因为它将PIP2转化为PIP3，PIP3经PLC-γ处理后释放IP3和DAG。DAG激活PKC家族，这有助于触发脱颗粒。IP3诱导钙从内 质网释放，这种钙内流是ADCC触发的主要信号之一，也导致核内NFAT易位，诱导其靶基因的转录。CD16a参与激活的其他途径也有助于ADCC，例如ERK2MAPK途径。CD16a依赖性NK细胞杀伤后，CD16a迅速下调。CD16a脱落的机制之一是由去整合素和金属蛋白酶17(ADAM17)介导的，后者在NK细胞上表达。ADAM17对CD16a的切割发生在顺式结构中，这意味着表达ADAM17的NK细胞不能在另一个NK细胞上诱导CD16a脱落。激活后CD16a下调的另一个机制是内化，这不仅发生在CD16a上，也发生在其他细胞内信号成分上，如CD3ζ、ZAP-70和Syk。
NK细胞作为先天性免疫细胞中的杀伤细胞，可直接杀伤病原体和肿瘤细胞。与T细胞相比，NK细胞具有更强的肿瘤识别和杀伤能力，以及更强的现货型应用的潜质。如何改造治疗性抗体药物的恒定区(Fc端)使其更好地激活先天免疫反应，增强抗体依赖的细胞毒作用(ADCC，antibody-dependent cell-mediated cytotoxicity)，如何评估能够特异性结合CD16A的双(多)抗药效是药物研发科学家所感兴趣的问题。目前提高ADCC作用的策略主要从下面几个方面：
(1)细胞因子：提高ADCC活性的一个简单方法是用促炎细胞因子刺激NK细胞。NK细胞移植已在多个临床试验中成功进行，例如通过输注细胞因子诱导记忆样(CIML)NK细胞，最常用的细胞因子组合包括IL-12、IL-15和IL-18。CIML NK细胞比传统NK细胞表达更多的IFN-γ，对白血病细胞和原发性急性髓系白血病(AML)母细胞显示出优越的细胞毒性。IL-12会增加NK细胞产生IFN-γ和TNF-α，在一项I/II期临床试验中，西妥昔单抗与IL-12联合应用于无法切除或复发的头颈部鳞状细胞癌患者。与无进展生存期(PFS)小于100天的患者相比，PFS大于100天的患者NK细胞在体外具有更高的ADCC活性。IL-15是NK和CD8+T细胞生存和功能所必需的细胞因子。N-803是一种突变的N72D IL-15超激动剂，在临床前模型和临床试验中显示出增强的NK细胞体外和体内活性。此外，它还增加了NK和CD8+T细胞的数量。
(2)抑制ADAM17：ADAM17是激活后CD16a下调的主要驱动因素。改善NK细胞ADCC的一种策略是通过靶向ADAM17来防止CD16a脱落。研究发现，对NK细胞中使用CRISPR/Cas9技术敲除ADAM17，显示出更好的IFN-γ生成和体内外ADCC活性。然而，也有研究显示，阻断ADAM17降低了NK细胞的存活率以及CD16a介导的连环杀伤，细胞无法与靶细胞分离，阻碍其运动到另一个靶细胞。总之，ADAM17抑制的益处尚不清楚，结果也有争议。这一策略是否能够成功，有待于一项正在进行的临床试验(NCT04023071)结果，该试验将评估携带不可切割CD16a的iPSC衍生NK细胞在AML和B细胞淋巴瘤中的应用。
(3)工程化抗体：抗体的Fc部分进行工程化改造，可以增加Fc对CD16a的亲和力，并随后改善ADCC。一些突变非常流行，例如，所谓的GASDALIE，由Fc中的4个替换组成：G236A/S239D/A330L/I332E。该突变显示对CD16a的亲和力显著增加，而CD32b亲和力几乎没有增 加。另一个突变称为突变体18(F243L/R292P/Y300L/V305I/P396L)，ADCC显著增加。这些突变现已作为抗HER2抗体margetuximab进入临床，并在I期治疗各种HER2阳性癌时显示出良好的效果。此外，抗体Fc N-聚糖的糖工程化有望增加对CD16a的亲和力。研究最多的糖修饰是去糖基化，例如去岩藻糖修饰。这种修饰导致与CD16a的结合增加，ADCC改善。这项技术已被用于抗CD20抗体obinutuzumab。
(4)NK细胞接合器：除了工程化抗体之外，还可以研究抗体的形式。基于双特异性T细胞接合器(BiTE)策略的成功，为NK细胞开发了一种类似的形式，即所谓的双特异性杀伤细胞接合器(BiKE)。BiKE由两个scFv通过连接序列组成，一个单链抗体靶向CD16a，另一个靶向肿瘤抗原。此外，还有三特异性杀伤细胞接合器(TRiKE)，有2种肿瘤抗原与CD16a一起被靶向，或者添加IL-15代替第三种单链抗体。这种结构的使用允许NK细胞重新定位到肿瘤细胞，并导致针对靶细胞的强大ADCC作用。AFM13是一种针对CD16a和CD30的双特异性抗体，目前处于临床Ⅱ期，用于治疗外周T细胞淋巴瘤、转化型蕈样变性和霍奇金淋巴瘤。在一项治疗复发或难治性霍奇金淋巴瘤的Ib临床研究中，AFM13与pembrolizumab的联合治疗产生了88％的客观反应率，总反应率为83％。GTB-3550是一种CD16/CD33/IL-15的TRiKE形式，目前正在进行多种类型白血病的I/II期试验研究(NCT03214666)。
然而，在大多数肿瘤中包括肠癌，肾癌，肝癌，乳腺癌和肺癌发现其肿瘤微环境中NK细胞的数目极少。因此，业内发展一种利用CD16A的活性来治疗癌症的免疫治疗方法，如具有肿瘤表面抗原特异性的抗体以及NK细胞CD16A特异性的抗体形成的双特异性分子，目前已经开发了HER2/neu和CD16A的双特异性抗体，比单独的HER2抗体具有更强的抗肿瘤活性；AFM13，一种特异性结合CD16A和CD30的双特异性抗体，通过结合NK细胞或单核细胞表面的CD16分子，使这些免疫效应细胞靶向表达CD30的肿瘤细胞进行杀伤，该抗体在霍奇金氏瘤的小鼠模型中还是患者中都表现出清除肿瘤的效果。但是传统的CD16A抗体或者抗CD16A抗原结合蛋白暴露一段时间会导致NK细胞衰竭或者NK细胞毒性效力减低，进而影响NK细胞的肿瘤杀伤作用。导致CD16A双抗不能长期给药，影响其效果。
白细胞介素-15(interleukin-15，IL-15)是一种长14–15kDa的细胞因子，对于NK细胞、NKT细胞和memory CD8+T细胞功能非常重要。IL-15通过与其受体IL-15Rα结合产生具有极高生物效价的复合物IL-15超激动剂(IL-15SA)后一起被转导转运至靶细胞。IL-15SA强烈激活响应表达IL-15R的细胞，特别是NK细胞/T细胞，从而促进抗肿瘤和抗病毒功能。IL-15具有广泛的免疫调节作用，能够参与调节T细胞，特别是NK细胞、记忆性CD8+T细胞的存活、增殖与功能。IL-15与IL-2结构十分相似，同属于螺旋型细胞因子家族。IL-15的异三聚体受体与IL-2受体共用IL-2R/IL-15Rβ(CD122)和共同γc链(CD 132)，由于这些共同的受体成分和共用JAK 1/JAK 3/STAT 5信号通路，IL-15与IL-2 具有相同的功能，包括刺激T细胞增殖、产生细胞毒性T淋巴细胞、刺激B细胞合成免疫球蛋白以及NK细胞的产生和持续存活。在许多适应性免疫应答中，IL-2和IL-15具有独特且常为竞争性的作用。主要有以下四点：1、IL-2可以调节Tregs细胞的激活，而IL-15则不能调节。2、IL-2可以通过激活诱导的CD8+效应T细胞的细胞死亡从而抑制T细胞反应。3、IL-15对NK、效应细胞CD8+和记忆表型CD8+T细胞的分化起着必不可少的作用。4、临床前研究标明，IL-15与IL-2的毒性不同，与IL-2相比，IL-15几乎观察不到血管毛细血管渗漏。这些因素使得IL-15成为肿瘤免疫策略中更具潜力的细胞因子。目前有多个IL-15靶点产品仍处于临床试验阶段，其中最值得关注的是IL-15超级激动剂N-803，为IL-15蛋白N72D突变后结合IL-15Ra及IgG1Fc共同表达的融合蛋白，2022年5月23日，ImmunityBio向FDA递交IL-15超级激动剂N-803的上市申请，用于与卡介苗(BCG)联合治疗卡介苗不响应的非肌肉浸润性膀胱癌(NMIBC)。2021年公布的临床数据，N-803+BCG联合治疗效果显著，CR率达到71％(59/83)，平均CR维持时间为24.1个月。一项1期临床实验显示，Nivolumab(PD-1抗体，Opdivo)联合N-803治疗转移性非小细胞肺癌的能够明显延长患者长期生存。基因泰克与Xencor公司合作开发IL-15细胞因子
Figure PCTCN2022117940-appb-000001
目前正在进行
Figure PCTCN2022117940-appb-000002
联用Tecentriq临床研究。恒瑞医药的SHR-1501(IL-15融合蛋白)于2019年5月14日获批开展SHR-1501临床试验。此外，SHR-1316(PD-L1单抗药物)将联合SHR-1501用于治疗失败的晚期恶性肿瘤患者。然而，细胞因子在临床上的使用存在着单药给药靶向性差的缺点，只有高浓度给药才可以达到抗肿瘤作用，而高浓度给药会产生免疫抑制作用和高毒性。并且，非靶向性细胞因子对于免疫系统的激活是系统性的，免疫系统被广泛的激活，具有致命的副作用。此外，由于细胞因子属于小分子量蛋白，不具备抗体的体内循环保护机制，单纯的细胞因子往往半衰期较短，需要短时间重复高剂量给药。目前临床研究药物多采用PEG化或者Fc融合来提高细胞因子的半衰期，虽然半衰期得以延长，但仍无法解决细胞因子的靶向性差的问题。
发明内容
本发明的第一目的是提供一种新型的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白。
本发明提供的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白包括：特异性结合CD16A的CD16A结合区、特异性结合肿瘤相关抗原(TAA)的TAA结合区、IL-15和IL-15Rα结合形成的IL-15/IL-15Rα复合物、以及Fc结构域。所述抗原包括肿瘤相关抗原(TAA)。本发明提供的三功能融合蛋白不仅同时靶向CD16A和TAA，还融合了IL-15/IL-15Rα复合物以及Fc结构域，其具有独特的组分并形成了独特的构型。此外，本发明的三功能融合蛋白利用IL-15及IL-15Rα分别替代双特异抗体的其中一个抗体结构中的CL及CH1结构域，通过IL-15与IL-15Rα之间的超高的亲和力(KD约 30-100pM)形成的IL-15/IL-15Rα结构，确保双特异抗体轻重链之间正确配对，进而解决双特异抗体轻链错配问题。同时，三功能融合蛋白CD16A抗体靶向NK细胞到肿瘤部位，并在肿瘤细胞附近激活NK细胞。传统的CD16A抗体或者抗CD16A抗原结合蛋白暴露一段时间会导致NK细胞衰竭或者NK细胞毒性效力减低，导致CD16A抗体不能长期给药，影响肿瘤治疗效果，但受损的NK细胞毒性可以通过本发明三功能融合蛋白结构当中的细胞因子IL-15和IL-15Rα刺激而恢复，进而增强NK细胞的肿瘤细胞杀伤作用，解决了CD16A抗体导致的NK细胞耗竭和肿瘤细胞毒性减弱问题。IL-15和IL-15Rα刺激NK细胞和T细胞等免疫效应细胞的增殖和激活，大大增强机体对肿瘤的免疫抑制活性。
可选的，所述CD16A结合区包括抗CD16A抗体或其抗原结合片段，优选的，所述CD16A结合区为靶向CD16A的Fab片段或Fv片段。
可选的，所述TAA结合区包括抗TAA抗体或其抗原结合片段，优选的，所述TAA结合区为靶向TAA的Fab片段或Fv片段。
可选的，所述的融合蛋白还包括连接片段；所述连接片段的氨基酸序列优选为若干个GS重复序列。
可选的，所述融合蛋白包含若干条肽链，所述IL-15和所述IL-15Rα分别位于不同肽链上。
可选的，所述三功能融合蛋白包括：1个所述的TAA结合区。
可选的，所述的融合蛋白包括：第一单体和第二单体；其中，所述第一单体包括：所述的TAA结合区和第一Fc链；所述第二单体包括：所述的CD16A结合区、所述的IL-15/IL-15Rα复合物和第二Fc链；所述TAA结合区为靶向TAA的Fab片段；所述CD16A结合区为靶向CD16A的Fv片段；或者，所述第一单体包括：所述的CD16A结合区和第一Fc链；所述第二单体包括：所述的TAA结合区、所述的IL-15/IL-15Rα复合物和第二Fc链；所述CD16A结合区为靶向CD16A的Fab片段；所述TAA结合区为靶向TAA的Fv片段；并且，所述第一Fc链和所述第二Fc链聚合形成所述的Fc结构域。
可选的，所述第一单体包括第一肽链和第二肽链，所述第二单体包括第三肽链和第四肽链；所述第一肽链包括：TAA结合抗体可变区、抗体恒定区；所述第二肽链包括：TAA结合抗体可变区、抗体恒定区；所述第二肽链的抗体恒定区包括第一Fc链；所述第三肽链包括：CD16A结合抗体可变区、细胞因子和第二Fc链；所述第四肽链包括：CD16A结合抗体可变区、细胞因子；所述第一肽链的TAA结合抗体可变区、抗体恒定区，以及所述第二肽链的TAA结合抗体可变区、抗体恒定区的配对区域形成所述的靶向TAA的Fab片段；所述第三肽链的CD16A结合抗体可变区和所述第四肽链的CD16A结合抗体可变区配对形成所述的靶向CD16A的Fv片段；所述第三肽链的细胞因子和所述第四肽链的细胞因子结合形成所述的IL-15/IL-15Rα复合物。
可选的，所述第一单体包括第一肽链和第二肽链，所述第二单体包括第三肽链和第四肽链；所述第一肽链包括：CD16A结合抗体可变区、抗体恒定区；所述第二肽链包括：CD16A结合抗体可变区、抗体恒定区；所述第二肽链的抗体恒定区包括第一Fc链；所述第三肽链包括：TAA结合抗体可变区、细胞因子和第二Fc链；所述第四肽链包括：TAA结合抗体可变区、细胞因子；所述第一肽链的CD16A结合抗体可变区、抗体恒定区，以及所述第二肽链的CD16A结合抗体可变区、抗体恒定区的配对区域形成所述的靶向CD16A的Fab片段；所述第三肽链的TAA结合抗体可变区和所述第四肽链的TAA结合抗体可变区配对形成所述的靶向TAA的Fv片段；所述第三肽链的细胞因子和所述第四肽链的细胞因子结合形成所述的IL-15/IL-15Rα复合物。
可选的，自肽链的N端到C端，所述第三肽链的融合顺序为：抗体可变区～细胞因子～第二Fc链，或为：细胞因子～抗体可变区～第二Fc链；自肽链的N端到C端，所述第四肽链的融合顺序为：抗体可变区～细胞因子；或为：细胞因子～抗体可变区；“～”表示连接片段；所述抗体可变区为CD16A结合抗体可变区或TAA结合抗体可变区。
可选的，所述三功能融合蛋白包括：2个所述的TAA结合区。
可选的，所述的融合蛋白包括：第一单体和第二单体；2个所述的TAA结合区分别为第一TAA结合区和第二TAA结合区；其中，所述第一单体包括：所述的第一TAA结合区和第一Fc链；所述第二单体包括：所述的CD16A结合区、所述的第二TAA结合区、所述的IL-15/IL-15Rα复合物和第二Fc链；所述第一TAA结合区为靶向TAA的Fab片段；所述CD16A结合区为靶向CD16A的Fv片段；所述的第二TAA结合区为靶向TAA的Fv片段；或者，所述第一单体包括：所述第一TAA结合区、所述的CD16A结合区和第一Fc链；所述第二单体包括：所述的第二TAA结合区、所述的IL-15/IL-15Rα复合物和第二Fc链；所述CD16A结合区为靶向CD16A的Fv片段；所述第一TAA结合区和所述所述第二TAA结合区均为靶向TAA的Fv片段；并且，所述第一Fc链和所述第二Fc链聚合形成所述的Fc结构域。
可选的，所述第一单体包括第一肽链和第二肽链，所述第二单体包括第三肽链和第四肽链；所述第一肽链包括：TAA结合抗体可变区、抗体恒定区；所述第二肽链包括：TAA结合抗体可变区、抗体恒定区；所述第二肽链的抗体恒定区包括第一Fc链；所述第三肽链包括：TAA结合抗体可变区、CD16A结合抗体可变区、细胞因子和第二Fc链；所述第四肽链包括：TAA结合抗体可变区、CD16A结合抗体可变区、细胞因子；所述第一肽链的TAA结合抗体可变区、抗体恒定区，以及所述第二肽链的TAA结合抗体可变区、抗体恒定区的配对区域形成所述的第一TAA结合区，所述的第一TAA结合区为靶向TAA的Fab片段；所述第三肽链的TAA结合抗体可变区和所述第四肽链的TAA结合抗体可变区配对形成所述的第二TAA结合区，所述的第二TAA结合区为靶向TAA的Fv片段；所述第三肽链的 CD16A结合抗体可变区和所述第四肽链的CD16A结合抗体可变区配对形成所述的CD16A结合区，所述CD16A结合区为靶向CD16A的Fv片段；所述第三肽链的细胞因子和所述第四肽链的细胞因子结合形成所述的IL-15/IL-15Rα复合物。
可选的，自肽链的N端到C端，所述第三肽链或所述第四肽链的氨基酸片段的融合顺序包括以下任意一种，其中“～”表示连接片段：
(1)TAA结合抗体可变区～CD16A结合抗体可变区～细胞因子；
(2)TAA结合抗体可变区～细胞因子～CD16A结合抗体可变区；
(3)CD16A结合抗体可变区～TAA结合抗体可变区～细胞因子；
(4)CD16A结合抗体可变区～细胞因子～TAA结合抗体可变区；
(5)细胞因子～TAA结合抗体可变区～CD16A结合抗体可变区；
(6)细胞因子～CD16A结合抗体可变区～TAA结合抗体可变区。
可选的，所述的融合蛋白包括：第一单体和第二单体；其中，所述第一肽链包括：TAA结合抗体可变区、CD16A结合抗体可变区和抗体恒定区；所述第二肽链包括：TAA结合抗体可变区、CD16A结合抗体可变区、抗体恒定区；所述第二肽链的抗体恒定区包括第一Fc链；所述第三肽链包括：TAA结合抗体可变区、细胞因子和第二Fc链；所述第四肽链包括：TAA结合抗体可变区、细胞因子；所述第一肽链的TAA结合抗体可变区和所述第二肽链的TAA结合抗体可变区配对形成所述的第一TAA结合区，所述的第一TAA结合区为靶向TAA的Fv片段；所述第一肽链的CD16A结合抗体可变区和所述第二肽链的CD16A结合抗体可变区配对形成所述的CD16A结合区，所述CD16A结合区为靶向CD16A的Fv片段；所述第三肽链的TAA结合抗体可变区和所述第四肽链的TAA结合抗体可变区配对形成所述的第二TAA结合区，所述的第二TAA结合区为靶向TAA的Fv片段；所述第三肽链的细胞因子和所述第四肽链的细胞因子结合形成所述的IL-15/IL-15Rα复合物。
可选的，在所述第一肽链或所述第二肽链中，自肽链的N端到C端，所述TAA结合抗体可变区和所述CD16A结合抗体可变区的融合顺序为：TAA结合抗体可变区～CD16A结合抗体可变区，或CD16A结合抗体可变区～TAA结合抗体可变区；“～”表示连接片段；或者，在所述第三肽链或所述第四肽链中，自肽链的N端到C端，所述TAA结合抗体可变区和所述细胞因子的融合顺序为：TAA结合抗体可变区～细胞因子，或细胞因子～TAA结合抗体可变区。
可选的，所述TAA结合抗体可变区选自靶向TAA的VH结构域或VL结构域，所述CD16A结合抗体可变区选自靶向CD16A的VH结构域或VL结构域，所述的细胞因子选自IL-15或IL-15Rα；所述的抗体恒定区包括CL结构域或CH1结构域。
可选的，所述的VH结构域和VL结构域之间具有一对或多对二硫键，并且包含以下突变组合形 式的任意一种以上，根据EU计数：
Figure PCTCN2022117940-appb-000003
可选的，所述IL-15包括：IL-15及其能结合IL-15Ra的突变，截短及各种衍生物；所述IL-15Ra包括：IL-15Ra及其能结合IL-15的突变，截短及各种衍生物；优选地，所述IL-15包括但不限于以下任意一组合所示的突变方式，计数方式根据IL-15的氨基酸序列的第一个氨基酸开始算为第1位；
组合 IL-15突变
1 N1D
2 N4D
3 D8N
4 D30N
5 D61N
6 E64Q
7 N65D
8 Q108E
9 N1D/D61N
10 N1D/E64Q
11 N4D/D61N
12 N4D/E64Q
13 D8N/D61N
14 D8N/E64Q
15 D61N/E64Q
16 E64Q/Q108E
17 N1D/N4D/D8N
18 D61N/E64Q/N65D
19 N1D/D61N/E64Q/Q108E
20 N4D/D61N/E64Q/Q108E
21 D30N/E64Q/N65D
；
或者，所述IL-15/IL-15Ra复合物包括但不限于以下任意一组合所示的突变方式，计数方式根据IL-15或IL-15Ra的氨基酸序列的第一个氨基酸开始算为第1位；
组合 IL15 IL15Ra
1 wt D96
2 wt D96/P97
3 wt D96/P97/A98
4 E87C D96/C97
5 E87C D96/P97/C98
6 E87C D96/C97/A98
7 V49C S40C
8 L52C S40C
9 E89C K34C
10 Q48C G38C
11 E53C L42C
12 C42S A37C
13 L45C G38C
14 L45C A37C
。
可选的，所述TAA选自CD20、CD19、CD30、CD33、CD38、CD40、CD52、slamf7、GD2、CD24、CD47、CD133、CD217、CD239、CD274、CD276、CEA、Epcam、Trop2、TAG72、MUC1、MUC16、mesothelin、folr1、CLDN18.2、EGFR、EGFR VIII、C-MET、HER2、FGFR2、FGFR3、PSMA、PSCA、EphA2、ADAM17、17-A1、NKG2D ligands、MCSP、LGR5、SSEA3、SLC34A2、BCMA、GPNMB、CCR4、VEGFR-2、CD6、整合素α4、PDGFRα、NeuGcGM3、整合素αVβ3、CD51、CTAA16.88、CD22、ROR1、CSPG4、SS1或IGFR1。
可选的，所述Fc结构域选自Human IgG1 Fc、Human IgG2 Fc、Human IgG3 Fc、Human IgG4 Fc或其变异体，优选自IgG1 Fc、或Human IgG4 Fc或其变异体；所述Fc结构域为Fc异源二聚体形式；优选地，所述Fc异源二聚体包含但不限于以下突变的组合，以下突变为根据EU计数：
Figure PCTCN2022117940-appb-000004
可选的，所述Fc结构域选择消除免疫效应功能，优选包含以下任一突变方式，以下突变为根据EU计数：
Figure PCTCN2022117940-appb-000005
可选的，所述第一Fc链不结合protein A，优选包括突变H435R或H435R/Y436F，根据EU计数；所述第二Fc链能够结合protein A。
可选的，所述CD16A结合区包括序列如SEQ ID NO:97所示的VH结构域和SEQ ID NO:96所示的VL结构域；或者，所述IL-15的序列如SEQ ID NO:104或105所示；或者，所述IL-15Ra的序列如SEQ ID NO:106至112中任意一项所示；优选的，所述CD16A结合区的VH和VL之间，和/或所述IL-15与IL-15Ra之间，至少具有一对以上二硫键。
可选的，由以下任意一组序列所示或与其具有90％以上同一性的氨基酸片段融合得到：
(1)SEQ ID NO:01、02、03、04；
(2)SEQ ID NO:01、05、03、06；
(3)SEQ ID NO:07、08、09、10；
(4)SEQ ID NO:01、02、11、12；
(5)SEQ ID NO:01、02、13、14；
(6)SEQ ID NO:01、05、11、15；
(7)SEQ ID NO:01、05、13、16；
(8)SEQ ID NO:38、39、40、41；
(9)SEQ ID NO:38、39、42、43；
(10)SEQ ID NO:38、39、44、45；
(11)SEQ ID NO:38、39、46、47；
(12)SEQ ID NO:48、49、50、51；
(13)SEQ ID NO:48、49、52、53；
(14)SEQ ID NO:48、49、54、55；
(15)SEQ ID NO:48、49、56、57；
(16)SEQ ID NO:58、59、60、61；
(17)SEQ ID NO:58、59、62、63；
(18)SEQ ID NO:58、59、64、65；
(19)SEQ ID NO:58、59、66、67；
(20)SEQ ID NO:68、69、70、71；
(21)SEQ ID NO:72、73、70、71；
(22)SEQ ID NO:74、75、70、71；
(23)SEQ ID NO:76、77、70、71；
(24)SEQ ID NO:78、79、70、71；
(25)SEQ ID NO:38、39、80、81；
(26)SEQ ID NO:38、39、82、83；
(27)SEQ ID NO:38、39、84、85；
(28)SEQ ID NO:38、39、86、87；
(29)SEQ ID NO:38、39、88、89；
(30)SEQ ID NO:38、39、90、91；
(31)SEQ ID NO:38、39、92、93；
(32)SEQ ID NO:38、39、94、95。
可选的，所述抗原还包括：传染性疾病相关抗原、病原体、免疫功能相关抗原。针对TAA以外的抗原时，将三功能融合蛋白中的特异性结合肿瘤相关抗原(TAA)的TAA结合区替换为相应的抗原结合区。
本发明还提供一种核酸分子，其编码所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融 合蛋白。
本发明还提供一种药物组合物，其含有所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，以及药学上可接受的载体。
本发明还提供所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白在制备用于抑制或治疗癌症、感染和免疫调节疾病的药物中的应用。
所述癌症包括前列腺癌、肺癌、结肠癌、直肠癌、膀胱癌、黑色素瘤、肾癌、口腔癌、咽癌、胰腺癌、子宫癌、甲状腺癌、皮肤癌、头颈癌、宫颈癌、卵巢癌或血液系统癌症。
本发明还提供一种蛋白的复合单元，所述复合单元包括：所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白中的第三肽链的CD16A结合抗体可变区和细胞因子、第四肽链的CD16A结合抗体可变区和细胞因子，以及若干连接片段；所述第三肽链的CD16A结合抗体可变区通过连接片段与所述第三肽链的细胞因子融合；所述第四肽链的CD16A结合抗体可变区通过连接片段与所述第四肽链的细胞因子融合；所述第三肽链的CD16A结合抗体可变区和所述第四肽链的CD16A结合抗体可变区选自靶向CD16A的VH结构域或VL结构域，并配对形成Fv片段；所述第三肽链的细胞因子和所述第四肽链的细胞因子选自IL15或IL15Rα，并结合形成IL-15/IL-15R复合物；优选的，所述VH结构域和VL结构域之间，和/或所述IL15和IL15Rα之间，具有一对以上的二硫键。
本发明还提供一种核酸分子，其编码所述的蛋白的复合单元。
发明的有益效果：
(1)本发明提供的三功能融合蛋白包括特异性结合CD16A的CD16A结合区、特异性结合肿瘤相关抗原(TAA)的TAA结合区、IL-15和IL-15Rα结合形成的IL-15/IL-15Rα复合物、以及Fc结构域，不仅能够同时靶向CD16A和TAA，还融合了IL-15/IL-15Rα复合物以及Fc结构域，其具有独特的组分并形成了独特的构型。
(2)本发明设计的TAA/CD16A/IL15三功能融合蛋白通过同时结合肿瘤细胞上的肿瘤相关抗原(TAA)和NK细胞上的CD16A，将NK细胞靶向肿瘤，NK细胞释放穿孔素、颗粒酶，引发细胞凋亡并导致肿瘤细胞死亡。细胞因子IL15扩增并维持NK细胞功能，刺激免疫细胞增殖，改变肿瘤的免疫微环境。
(3)本发明构建的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，具有IL-15/IL-15Rα活性，能够将细胞因子靶向到肿瘤部位，可以特异的在肿瘤部位扩增和活化免疫效应细胞(NK细胞及T细胞)，使免疫细胞数目以及杀伤性细胞因子的释放增加，更加有效地激活免疫反应杀伤肿瘤细胞。
(4)将IL-15和IL-15Rα替换抗体结构中的CL和CH1结构域，利用IL-15和IL-15Rα的高亲和 力形成IL-15/IL-15Rα复合物，从而实现双特异抗体轻链的正确配对，解决双特异性抗体轻链错配问题。另外，可通过氨基酸序列突变，在VH和VL之间，以及IL-15和IL-15Rα之间添加一对或多对二硫键，进一步地增强轻链/重链间的结合活性，结合Fc异源二聚体技术解决双特抗体重链错配问题，更有效克服双特异性抗体制备过程中轻链、重链错配、副产物高、稳定性差等挑战，制备得到正确配对的多功能融合蛋白，同时，缩短多功能融合蛋白开发周期，降低生产成本。
(5)可保留Fc结构域的效应功能，或采用消除免疫效应形式的Fc结构域。采用消除免疫效应形式的Fc结构域使Fc不能结合FcRγIII(CD16A)。本发明的融合蛋白若保留Fc结构域的效应功能，也观察到免疫细胞相对应的激活效果。
附图说明
图1至图19分别为本发明的不同实施例中的三功能融合蛋白的结构形式示意图，其中图1至图9所示为TAA结合区和CD16A结合区比为1：1形式的三功能融合蛋白；图10至图19所示为TAA结合区和CD16A结合区比为2：1形式的三功能融合蛋白。
图20和图21为FACS检测三功能蛋白结合HL60细胞的结果图。
图22、图23、图24为FACS检测CD38/CD16A/IL-15三功能融合蛋白结合Daudi细胞的结果图。
图25为ELISA检测三功能分子结合CS1蛋白的结果图。
图26至图32为CCK8检测TAA/CD16A/IL-15三功能融合蛋白对Mo7e细胞增殖实验的结果图。
图33至图38为CD33/CD16A/IL-15三功能融合蛋白介导的ADCC作用的结果图，其中图33、图34效靶比为10:1，图35效靶比为20:1，图36、图37、图38效靶比为10:1。
图39至图42为CD38/CD16A/IL-15三功能融合蛋白介导的ADCP的结果图，其中图39效靶比为10:1，图40效靶比为5:1，图41和图42效靶比为10:1。
图43为CD33/CD16A/IL-15三功能融合蛋白介导的ADCP的结果图。
具体实施方式
以下结合附图和实施例对本发明的技术方案做进一步的说明。为了更容易理解本发明，以下具体定义了某些技术和科学术语。除显而易见在本文的它处另有明确定义，否则本文中使用的所有其他技术和科学术语都具有本领域技术人员通常理解的含义。
术语
术语“融合”指由肽键直接连接或借助连接片段连接组分，或通过分子间相互作用非共价融合或通过一个或多个二硫键或化学交联共价融合。在单条肽链中，融合是指由肽键直接连接或借助连接片段 连接。“多功能融合蛋白”是指包含两个或更多个抗原结合结构域的蛋白，能够结合两个或更多个不同的表位(例如，两个、三个或更多个不同的表位)，多功能融合蛋白还可以包含细胞因子(例如IL-15、IL-15Ra)等。“融合位置”是指功能区或者结构域在肽链中的位置，指示该肽链上各功能片段的连接顺序。
术语“多肽”是指任何长度的氨基酸链，包括蛋白质及其片段。本发明将多肽公开为氨基酸残基序列。那些序列按氨基末端到羧基末端的方向从左到右书写。根据标准命名法，氨基酸残基序列以三字母或单字母代码命名，如下所示：丙氨酸(Ala,A)、精氨酸(Arg,R)、天冬酞胺((Asn,N)、天冬氨酸(Asp，D)、半肌氨酸(Cys,C)、谷氨酞胺(Gln,Q)、谷氨酸(Glu,E)、甘氨酸(Gly,G)、组氨酸(His,H)、异亮氨酸(I1e，I)、亮氨酸(Leu,L)、赖氨酸(Lys,K)、甲硫氨酸(Met,M)、苯丙氨酸(Phe，F)、脯氨酸(Pro,P)、丝氨酸(Ser,S)、苏氨酸(Thr,T)、色氨酸(Trp,W)、酪氨酸(Tyr,Y)和缬氨酸(Val,V)。
术语“肽链”指由肽键线性连接氨基酸的分子。
术语“变异体”或“突变体”是指与包含的氨基酸或核苷酸有所不同但保持基本特性的多肽或多核苷酸。通常变异体之间或者变异体与母本抗体之间的差异是有限的，氨基酸序列总体上非常相似。本说明书中，将变异前的抗体或抗体片段称为母本抗体，变异后的抗体或抗体片段称为变异体。变异体仍具有抗原结合活性。
术语“抗体”(antibody，Ab)指包含至少一个抗原结合位点并能特异性结合抗原的免疫球蛋白分子(immunoglobulin，Ig)。
术语“抗原”是在机体内能诱发免疫应答且与抗体特异性结合的物质。抗体与抗原的结合依靠二者间形成的相互作用来介导，包括氢键、范德华力、离子键以及疏水键。抗原表面与抗体结合的区域为“抗原决定簇”或“表位”，一般来说，每个抗原有多个决定簇。
本发明所提及的术语“抗体”以其最广泛的含义理解，并包含单克隆抗体(包括全长单克隆抗体)、多克隆抗体、抗体片段、包含至少两个不同的抗原结合结构域的多特异性抗体(例如，双特异性抗体)。抗体还包括鼠源抗体、人源化抗体、嵌合抗体、人抗体以及其它来源的抗体。本发明的抗体可以来源于任何动物，包括但不限于人、非人灵长类动物、小鼠、大鼠、牛、马、鸡、骆驼、羊驼的免疫球蛋白分子等。抗体可以含有另外的改变，如非天然氨基酸，Fc效应子功能突变和糖基化位点突变。抗体还包括翻译后修饰的抗体、包含抗体的抗原决定簇的融合蛋白，以及包含对抗原识别位点的任何其它修饰的免疫球蛋白分子，只要这些抗体展现出所期望的生物活性。换句话说，抗体包括免疫球蛋白分子和免疫球蛋白分子的免疫活性片段，即至少含有一个抗原结合结构域的分子。
抗体的基本结构是由两条完全相同的重链(heavy chain，H)和两条完全相同的轻链(light chain，L)通过二硫键连接的呈Y形的单体。每条链分别由2～5个约含110个氨基酸，序列相似但功能不同 的结构域(又称功能区)组成。抗体分子中轻链和重链靠近N端的氨基酸序列变化较大，形成的结构域称为可变区(variable region，V区)；靠近C端的氨基酸序列相对恒定的区域称为恒定区(constant region，C区)。
重链和轻链的V区分别称为VH和VL，VH和VL各有3个区域的氨基酸组成和排列顺序高度可变，称为高变区(hypervariable region，HVR)；该区域形成与抗原表位互补的空间构象，又被称为互补决定区(complementarity determining region，CDR)。VH的3个CDR分别用VHCDR1、VHCDR2、VHCDR3表示，VL的3个CDR分别用VLCDR1、VLCDR2、VLCDR3表示。VH和VL共6个CDR共同组成抗原结合部位(antigen-binding site)。CDR区氨基酸的多样性是抗体与数量庞大的不同抗原特异性结合的分子基础。V区中CDR之外的氨基酸组成和排列顺序相对变化不大，称为骨架区(framework region，FR)。VH和VL各有4个骨架区(或称框架区)，分别用FR1、FR2、FR3、FR4表示。每个VH和VL有三个CDR和四个FR组成，从氨基端到羧基端排列顺序为：FR1、CDR1、FR2、CDR2、FR3、CDR3、FR4。
根据抗体重链恒定区的氨基酸序列，可以将人免疫球蛋白分为5类：IgM、IgG、IgA、IgD、IgE。其还可以进一步分成不同的亚类(同种型)，如人IgG可以分为IgG1、IgG2、IgG3、IgG4；IgA可分为IgA1和IgA2。IgM、IgD、IgE尚未发现有亚类。根据轻链氨基酸序列，可将轻链分类为κ链和λ链。本发明的抗体可以是任何种类(如IgM、IgG、IgA、IgD、IgE)或亚类(如IgG1、IgG2、IgG3、IgG4、IgA1、IgA2)。
重链和轻链的恒定区分别称为CH和CL。IgG、IgA、IgD的重链恒定区有CH1、CH2、CH3三个结构域，IgM、IgE的重链恒定区有CH1、CH2、CH3、CH4四个结构域。
铰链区(hinge region)位于CH1和CH2之间，含有丰富的脯氨酸，因此易伸展弯曲，能改变Y形两个臂之间的距离，有利于两臂同时结合抗原表位。
术语“Fab片段”为抗原结合片段(fragment of antigen binding,Fab)，意指由VL、VH、CL和CH1结构域组成的抗体片段，与单个抗原表位结合(单价)。本领域技术人员可知，在一定条件下，抗体分子链的某些部分易被蛋白水解酶水解为各种片段。木瓜蛋白酶从铰链区的近N端，将抗体分子水解为2个完全相同的抗原结合片段(Fab)和一个可结晶片段(Fc)。
术语“Fv片段”是由L链和H链的V区(VH+VL)组成的单价小分子，是与抗原结合的最小功能片段。
术语“Fc”、“Fc段”、“Fc片段”“Fc结构域”，是指可结晶片段(fragment crystallizable)，无抗原结合活性，是抗体与效应分子或细胞表面Fc受体(FcR)相互作用的部位。Fc片段与表面具有相应Fc受体的细胞结合，产生不同的生物学作用。在ADCC效应中(抗体依赖的细胞介导的细胞毒性作用， antibody-dependent cell-mediated cytotoxicity)，抗体的Fab段结合病毒感染的细胞或肿瘤细胞的抗原表位，其Fc段与杀伤细胞(NK细胞、巨噬细胞等)表面的FcR结合，介导杀伤细胞直接杀伤靶细胞。Fc片段包含抗体除重链恒定区CH1之外的恒定区多肽，即人免疫球蛋白IgA、IgD、IgG重链恒定区羧基端的两个恒定区结构域CH2及CH3，以及人免疫球蛋白IgE和IgM重链恒定区羧基端的三个恒定区结构域CH2，CH3及CH4。Fc片段常选自Human IgG1 Fc、Human IgG2 Fc、Human IgG3 Fc、Human IgG4 Fc或其变异体，优选自IgG1 Fc、或Human IgG4 Fc或其变异体
Fc可由两条链组成，本文中将Fc片段的两条链描述为第一Fc链和第二Fc链，第一Fc链和第二Fc链可以分别进行突变，本发明并不做特别限定。Fc片段也可指Fc结构域中的单条多肽链。抗体的Fc段可选择消除免疫效应功能，包含但不限于以下突变的组合(根据EU计数)
Figure PCTCN2022117940-appb-000006
经突变设计的Fc变体之间可以形成空间填充效应、静电转向、氢键作用、疏水作用等。Fc变体间相互作用有助于形成稳定的异源二聚体。优选的突变设计为“Knob-in-hole"形式的突变设计。
“连接片段”是指插入免疫球蛋白结构域中并提供足够的可动性的一个或多个氨基酸残基，需保证蛋白质的正确折叠和肽稳定性。“连接片段”优选为(GGGGS)n，其中n可以为0、1、2、3、4、5或者更多。如果连接片段序列太短，可能影响两蛋白高级结构的折叠，从而相互干扰；如果连接肽序列太长，又涉及免疫原性的问题，因为连接肽序列本身就是新的抗原。
肿瘤相关抗原(tumor-associated antigen，TAA)，是指在肿瘤细胞或正常细胞上存在的抗原分子，包括：胚胎性蛋白、糖蛋白抗原、鳞状细胞抗原等，常用于临床肿瘤的诊断。肿瘤相关抗原并非肿瘤细胞所特有，正常细胞可微量合成，而在肿瘤细胞增殖时高度表达，因此称为“相关抗原”。肿瘤相关抗原例如可以是CD20、CD19、CD30、CD33、CD38、CD40、CD52、slamf7、GD2、CD24、CD47、CD133、CD239、CD276、PD-1、CEA、Epcam、Trop2、TAG72、MUC1、MUC16、mesothelin、folr1、CLDN18.2、PDL1、EGFR、EGFR VIII、C-MET、HER2、FGFR2、FGFR3、PSMA、PSCA、EphA2、ADAM17、17-A1、NKG2D ligands、MCSP、LGR5、SSEA3、SLC34A2、BCMA、GPNMB或Glypican-3。
术语“载体”意指能够转运与其连接的另一多核苷酸的多核苷酸分子。一种类型的载体是“质粒”，其是指环状双链DNA环，其中可以连接附加的DNA区段。另一种类型的载体是病毒载体，其中附加的DNA区段可以连接到病毒基因组中。某些载体能够在引入它们的宿主细胞中自主复制(例如，具有细菌复制起点的细菌载体和附加型哺乳动物载体)。其他载体(例如非附加型哺乳动物载体)可以在引入宿主细胞中后整合到宿主细胞的基因组中，从而与宿主基因组一起复制。此外，某些载体能够指导与它们可操作地连接的基因的表达。通常，在重组DNA技术中有用的表达载体通常呈质粒的形式。本发明可提供包含有能够编码三功能融合蛋白的核酸片段的载体。
术语“IL-15”、“IL-15Ra”可以是其突变体或片段。本发明所述的“IL-15”可以是任何IL-15或能结合IL-15Rα的突变体，如人IL-15或非人哺乳动物或非哺乳动物的IL-15。示例性非人哺乳动物如猪、兔、猴、猩猩、鼠等，非哺乳动物如鸡等；优选人的IL-15。术语“能结合IL-15Rα的突变体”指通过一个或多个氨基酸替换、增加或者缺失突变获得的对IL-15与其受体间亲和力提高或者降低，或其刺激T细胞或者NK细胞活性增加或者降低的突变体分子。
本发明中所述的“IL-15Rα”可以是任何物种的IL-15Rα或者能结合IL-15Rα的突变体，如人IL-15Rα或非人哺乳动物IL-15Rα或非哺乳动物IL-15Rα。示例性非人哺乳动物如猪、兔、猴、猩猩、鼠等，非哺乳动物如鸡等。优选人的IL-15Rα，更优选人IL-15Rα胞外域片段，简称IL-15RαECD(见数据库UniProtKB，登录号Q13261，31-205aa)。术语“能结合IL-15Rα的突变体”指在IL-15Rα上通过一个或者多个氨基酸缺失、插入或替换突变形成的具有与其配体分子如IL-15结合能力的功能性突变体，优选人的IL-15Rα分子更优选人的IL-15Rα胞外域片段的缩短形式，即从胞外域片段C端开始通过一个或多个氨基酸缺失突变所得的具有人IL-15受体α活性的分子，优选保留65-178个氨基酸的缺失突变 形式，比如IL-15Rα。IL-15蛋白本身不如与IL-15Rα蛋白复合时稳定。如本领域已知的，IL-15Rα蛋白含有“sushi结构域”，其是保留IL-15结合活性的受体的最短区域，或胞外区中能够保持90％以上结合活性的一个结构域。
CS1(也称CD319，SLAMF7)为信号淋巴细胞活化分子家族成员7，是调节NK细胞免疫功能的表面受体蛋白。CS1在多发性骨髓瘤(MM)细胞系中高度表达，但在健康组织，原发性肿瘤组织或血液学和非血液学癌症细胞系未发现，使其成为治疗该疾病的诱人靶标。
CD33是67kD的单通跨膜糖蛋白并且是唾液酸结合免疫球蛋白样凝集素(Siglecs)家族的成员。虽然其确切的生物学功能尚不清楚，但在正常个体中，其主要被认为是髓细胞样分化抗原，在髓细胞样祖细胞、中性粒细胞和巨噬细胞中表达较低，而在循环的单核细胞和树突状细胞中高度表达。重要的是，已在85％至90％的患有急性髓性白血病(AML)的患者的母细胞和白血病干细胞中检测到CD33。有趣的是，CD33的表达仅限于造血细胞(Paul、Taylor、Stansbury和McVicar，2000年；Ulyanova、Blasioli、Woodford-Thomas和Thomas，1999年)，但是在正常造血干细胞上却不存在(Andrews、Torok-Storb和Bernstein，1983年Griffin、Linch、Sabbath、Larcom和Schlossman，1984；Jilani等人，2002年)。这些发现表明CD33是AML中基于抗体的疗法的合适靶标。
CD38抗原于1980年被发现，是一种大小为46kDa的II型跨膜糖蛋白。CD38的配体为CD31，也称为PECAM-1，它是Ig基因超家族的成员。CD31除了在内皮细胞上表达外，还在淋巴样细胞(卵泡膜B细胞和浆细胞)、肺(肺泡管、肺泡和淋巴管)和肾脏(肾小球细胞)中表达。CD38与配体CD31相互作用，在调节细胞迁移、受体介导的粘附以及信号传导中扮演着重要角色。此外，CD38蛋白质还是一种双功能胞外酶，兼具环化酶和水解酶的活性，参与核苷酸代谢。CD38使用NAD+作为底物来形成环状ADP核糖(cADPR)和ADPR，这些核苷酸代谢产物是有效的第二信使，可调节细胞质中钙离子的动员，激活控制各种生物学过程的信号通路，例如淋巴细胞增殖、胰腺B细胞分泌胰岛素等等。还有研究表明，CD38依赖性腺苷的产生在由自然杀伤(NK)细胞介导的免疫抑制中也起着关键作用。通常，CD38在正常淋巴样细胞和髓样细胞以及非造血组织上低水平表达，而在造血起源的细胞(包括定型干细胞)上广泛表达。CD38在B细胞中表达，而浆细胞(也称效应B细胞)中的CD38表达水平特别高。CD38的表达与多种疾病有关，包括艾滋病、自身免疫性疾病(例如系统性红斑狼疮)、2型糖尿病、骨质疏松症和癌症。研究发现，CD38在大量恶性血液癌症中高度表达，特别是在多发性骨髓瘤等癌症中，这使CD38成为多发性骨髓瘤治疗性抗体药物的开发靶点。
“效应子功能”意指由抗体Fc区与Fc受体或配体的相互作用产生的生物化学事件。效应子功能包括但不限于ADCC、ADCP和CDC。“ADCC”或“抗体依赖性细胞介导的细胞毒性”意指细胞介导的反应，其中表达FcγR的非特异性细胞毒性细胞识别靶细胞上的结合抗体，并且随后引起靶细胞的裂解。 ADCC与FcγRIIIa的结合相关联；与FcγRIIIa的结合增加导致ADCC活性中的增加。如本文讨论的，本发明的许多实施例完全消除了ADCC活性。“ADCP”或抗体依赖性细胞介导的吞噬作用意指细胞介导的反应，其中表达FcγR的非特异性细胞毒性细胞识别靶细胞上的结合抗体，并且随后引起靶细胞的吞噬作用。
就蛋白质序列而言的“百分比(％)氨基酸序列同一性”定义为，在比对序列且必要时引入缺口以实现最大百分比序列同一性，并且不考虑任何保守取代作为序列同一性的部分，候选序列中与特定(亲本)序列中的氨基酸残基相同的氨基酸残基的百分比。在一些实施例中，两个或更多个氨基酸序列是至少80％、85％或90％相同的。在一些实施例中，两个或更多个氨基酸序列是至少95％、97％、98％、99％或甚至100％相同的。
术语“第一”、“第二”仅用于描述目的，并不指示或暗示其重要性程度。
本发明的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白包括：特异性结合CD16A的CD16A结合区、特异性结合肿瘤相关抗原(TAA)的TAA结合区、IL-15和IL-15Rα结合形成的IL-15/IL-15Rα复合物、以及Fc结构域。本发明的TAA/CD16A/IL-15三功能融合蛋白发挥治疗作用，主要是通过同时结合肿瘤细胞上表达的肿瘤相关抗原(TAA)和NK细胞上的CD16A，将这两种细胞交联形成免疫突触，促进NK细胞杀死肿瘤细胞，同时IL-15扩增并维持NK细胞功能。
在一些实施例中，本发明融合蛋白的TAA结合区和CD16A结合区为1：1形式，在另一些实施例中，为2：1形式。
1：1形式的三功能融合蛋白的结构可参阅图1至图9。融合蛋白由四条肽链融合形成，第一肽链和第二肽链形成第一单体(图中左侧部分)，第三肽链和第四肽链形成第二单体(图中右侧部分)。第一肽链包括：由VL结构域和CL结构域融合形成的轻链，第二肽链包括：由VH结构域、CH1结构域和第一Fc链融合形成的重链；第一肽链的VL结构域、CL结构域，以及所述第二肽链的VH结构域、CH1结构域配对形成Fab片段。第三肽链包括：抗体可变区、细胞因子和第二Fc链；第四肽链包括：抗体可变区、细胞因子。第三肽链的抗体可变区和所述第四肽链的抗体可变区配对形成Fv片段，第三肽链的细胞因子和所述第四肽链的细胞因子结合形成所述的IL-15/IL-15Rα复合物。
在图1至图8所示的融合蛋白中，第一单体中的Fab片段靶向TAA，实现图中TAA Antibody的功能。在第二单体中，配对形成Fv片段的抗体可变区选自VH结构域和VL结构域，例如，第三肽链中的抗体可变区选择靶向CD16A的VH结构域，第四肽链的抗体可变区选择靶向CD16A的VL结构域，VH和VL配对形成靶向CD16A的Fv片段，实现图中Anti-CD16A Antibody的功能。另一些实施例中，第三肽链中的抗体可变区选择靶向CD16A的VL结构域，第四肽链的抗体可变区选择靶向CD16A的VH结构域。图中的VH(L)表示选择VH或VL。图中“VH(L)1”、“VL(H)1”、“VH2”、 “VL2”中的数字仅用于描述目的，表示靶向不同抗原的抗体可变区。VH(L)1表示可以选择VH1也可以选择VL1，若第三肽链的抗体可变区选择VH1，则第四肽链的抗体可变区应选择VL1，从而能够配对形成Fv片段。第三肽链和第四肽链中的细胞因子选自IL-15和IL-15Rα，形成IL-15/IL-15Rα复合物(IL-15/IL-15Rαcomplex)。一些实施例中，第三肽链中的细胞因子选择IL-15，第四肽链中的细胞因子选择IL-15Rα。一些实施例则相反，第三肽链选择IL-15Rα，第四肽链选择IL-15。
在第三肽链和第四肽链中，并不限定抗体可变区(VH或VL)与细胞因子的融合顺序。例如，图1所示的融合蛋白中，自肽链的N端到C端，所述第三肽链的融合顺序为：抗体可变区～细胞因子～第二Fc链，第四肽链的融合顺序为：抗体可变区～细胞因子，“～”表示连接片段。图2所示的融合蛋白与图1的区别在于，自肽链的N端到C端，第四肽链的融合顺序为：细胞因子～抗体可变区。图1至图8中的圆球形和月牙形代表不同的细胞因子，以下假设圆球形代表IL-15，则月牙形则代表IL-15Ra。自肽链的N端到C端，图1至图8所示的融合蛋白，其第三肽链和第四肽链的可能组合形式列示如下：
表1融合蛋白第三肽链和第四肽链的组合形式
Figure PCTCN2022117940-appb-000007
Figure PCTCN2022117940-appb-000008
图9所示的融合蛋白，其第一单体中(图中左侧部分)的Fab片段靶向CD16A，实现图中Anti-CD16A Antibody的功能。Fv片段靶向TAA，实现图中Anti-TAA Antibody的功能。类似于图1至图8所示的融合蛋白，图9所示的融合蛋白也可具有表1所列的第三肽链和第四肽链的多种可能组合形式。
TAA结合区和CD16A结合区为2：1形式的三功能融合蛋白的结构可参阅图10至图19。融合蛋白由四条肽链融合形成，第一肽链和第二肽链形成第一单体(图中左侧部分)，第三肽链和第四肽链形成第二单体(图中右侧部分)。可参阅图10至图13，在一些实施例中，第一单体包括一个TAA结合区(TAA antibody)和一条Fc链，第二单体包括CD16A结合区(CD16A antibody)、一个TAA结合区(TAA antibody)、IL-15/IL-15Rα复合物(IL15/IL15Ra complex)和一条Fc链，两条FC链聚合形成Fc结构域(Fc Heterodimer)。
更具体的，2个TAA结合区分别为第一TAA结合区和第二TAA结合区。可参阅图10，在一些实施例中，2：1形式的三功能融合蛋白的第一肽链包括：TAA结合抗体可变区(例如抗TAA的VL结构域)、抗体恒定区(例如CL结构域)；第二肽链包括：TAA结合抗体可变区(例如抗TAA的VH结构域)、抗体恒定区(例如CH1结构域和第一Fc链)；第三肽链包括：TAA结合抗体可变区(例如抗TAA的VH结构域)、CD16A结合抗体可变区(例如抗CD16A的VL结构域)、细胞因子(例如IL-15)和第二Fc链；第四肽链包括：CD16A结合抗体可变区(例如抗CD16A的VH结构域)、TAA结合抗体可变区(例如抗TAA的VL结构域)、细胞因子(例如IL-15Ra)。第一肽链的VL、CL，以及第二肽链的VH、CH1配对形成所述的第一TAA结合区，所述的第一TAA结合区为靶向TAA的Fab片段。第三肽链的TAA结合抗体可变区和第四肽链的TAA结合抗体可变区配对形成第二TAA结合区，第二TAA结合区为靶向TAA的Fv片段；第三肽链的CD16A结合抗体可变区和第四肽链的CD16A结合抗体可变区配对形成CD16A结合区，CD16A结合区为靶向CD16A的Fv片段(第二TAA结合区和CD16A结合区形成diabody形式的抗体片段)；第三肽链的细胞因子和第四肽链的细胞因子结合形成IL-15/IL-15Rα复合物。
图10和图11所示的三功能融合蛋白(形式1A至1D)，其针对相同的靶点并具有相同的结构域，区别在于第三肽链和第四肽链中的结构域的融合顺序不同。例如在图10中，形式1A的三功能融合蛋 白，其第三肽链的结构域自N端到C端的融合顺序为：VH(anti TAA)～VL(anti CD16A)～IL-15Ra～第二Fc链；其第四肽链的结构域自N端到C端的融合顺序为：VH(anti CD16A)～VL(anti TAA)～IL-15。而形式1B的三功能融合蛋白，其第三肽链的结构域自N端到C端的融合顺序为：VH(anti CD16A)～VL(anti TAA)～IL-15Ra～第二Fc链；其第四肽链的结构域自N端到C端的融合顺序为：VH(anti TAA)～VL(anti CD16A)～IL-15。
图12中，形式2A和形式2B所示的三功能融合蛋白，细胞因子的两侧均融合抗体可变区。图13中，形式3A和形式3B所示的三功能融合蛋白，细胞因子融合在肽链的端侧。
参阅图14至图19，在一些实施例中，第一单体包括CD16A结合区、一个TAA结合区和一条Fc链，第二单体包括一个TAA结合区、IL-15/IL-15Rα复合物和一条Fc链，两条FC链聚合形成Fc结构域。图14和图15中，形式4A至形式4D所示的三功能融合蛋白，其第一肽链和第二肽链的抗体可变区的融合顺序有所不同，并且细胞因子融合于抗体可变区和FC链之间。图16和图17中，形式5A至形式5D所示的三功能融合蛋白，其细胞因子融合于端则。图18和图19中，形式6A至形式6D所示的三功能融合蛋白，其第一单体中，类似于DVD-Ig双抗，在抗体轻链和重链的N末端分别接入另一个抗体的VL和VH结构域。例如形式6A所示的三功能融合蛋白，其第一肽链各结构域的融合顺序为：VL(anti TAA)～VL(anti CD16A)～CL；其第二肽链的融合顺序为；VH(anti TAA)～VH(anti CD16A)～CH1～Fc。其细胞因子可以融合于抗体可变区及第二Fc链之间，也可以融合在端侧。
本发明并不限定融合蛋白中各结构域的融合顺序，除上述所列实施例外，本领域技术人员可以做其他变换。
本发明提供的具有创新结构蛋白的复合单元，可参阅图1所示融合蛋白的第二单体的上部，即抗CD16A的Fv片段与IL-15/IL-15Rα复合物融合的区域。复合单元包括：两个抗体可变区(抗CD16A的VH和VL)、两个细胞因子(IL-15、IL-15Ra)、若干连接片段。一个抗体可变区通过连接片段与一个细胞因子融合。两个抗体可变区配对形成Fv片段，两个细胞因子结合形成IL-15/IL-15R复合物。抗CD16A的VH结构域和VL结构域之间，和/或IL15和IL15Rα之间，优选具有一对以上的二硫键，从而形成更稳定的结构。可以在VH和VL之间设二硫键，IL15和IL15Rα之间不设二硫键；也可以在IL15和IL15Rα之间设二硫键，VH和VL之间不设二硫键；或者，在VH和VL之间，以及IL15和IL15Rα之间均设二硫键。利用本发明提供的复合单元，本领域技术人员可用于构建其他目的蛋白，而不限于本发明实施例所举例说明的融合蛋白的形式。
细胞因子IL-15与IL-15Ra之间有超高的亲和力(KD约30-100pM)，本发明可用IL-15及IL-15Ra分别替代其中一个抗体结构中的CL及CH1结构域，解决双特异抗体轻链错配问题，通过FC异源二聚体形式解决重链错配。一些实施例中，将有Fab的FC端进行突变，使其不能结合Protein A。纯化 通过结合FC端的Protein A亲和层析及结合CH1结构域CH1-XL亲和层析的2步纯化出双特异靶向抗体。
实施例1：TAA/CD16A/IL-15三功能融合蛋白获得，分子克隆，瞬转表达，及蛋白纯化
分子克隆：本实施例根据表2和表3构建多个融合蛋白，TAA分别选择CD33、CD38、CS1。蛋白表达及序列号如下表所示。表2构建获得的三功能融合蛋白，其TAA结合区和CD16A结合区为1：1形式；表3构建获得三功能融合蛋白，双下划线蛋白编号所示的融合蛋白为1：1形式，其余为2：1形式。表2和表3还提供了结构描述，以QP743745为例，由结构描述可知，其包括四条肽链，四条肽链的融合顺序分别为：
(1)antiCD16A.VL～IL-15；
(2)antiCD16A.VH～IL-15Ra～Fc(采用knob突变)；
(3)antiCD33.VL～CL；
(4)antiCD33.VH～CH1～Fc(采用hIgG1，Hole突变，另含有突变位点H435R)。
表2：克隆设计构建
Figure PCTCN2022117940-appb-000009
Figure PCTCN2022117940-appb-000010
表3：克隆设计构建
Figure PCTCN2022117940-appb-000011
Figure PCTCN2022117940-appb-000012
Figure PCTCN2022117940-appb-000013
Figure PCTCN2022117940-appb-000014
Figure PCTCN2022117940-appb-000015
SEQ ID NO:01序列如下：
Figure PCTCN2022117940-appb-000016
Figure PCTCN2022117940-appb-000017
其中，虚线所指序列为antiCD16A的VL，波浪线所指序列为IL-15。
SEQ ID NO:02序列如下：
Figure PCTCN2022117940-appb-000018
Figure PCTCN2022117940-appb-000019
其中，虚线所指序列为antiCD16A的VH，波浪线所指序列为IL-15Ra，双下划线为Fc(Knob突变)。
SEQ ID NO:03序列如下：
Figure PCTCN2022117940-appb-000020
Figure PCTCN2022117940-appb-000021
其中，下划线以外的部分为antiCD33的轻链序列，虚线所指序列为VL。
SEQ ID NO:04序列如下：
Figure PCTCN2022117940-appb-000022
Figure PCTCN2022117940-appb-000023
其中，下划线以外的部分为antiCD33的重链序列，虚线所指序列为VH。另提供以下序列：
antiCD16A VL SEQ ID NO:96
Figure PCTCN2022117940-appb-000024
antiCD16A VH SEQ ID NO:97
Figure PCTCN2022117940-appb-000025
antiCD38 VL SEQ ID NO:98
Figure PCTCN2022117940-appb-000026
antiCD38 VH SEQ ID NO:99
Figure PCTCN2022117940-appb-000027
antiCS1 VL SEQ ID NO:100
Figure PCTCN2022117940-appb-000028
antiCS1 VH SEQ ID NO:101
Figure PCTCN2022117940-appb-000029
antiCD33 VL SEQ ID NO:102
Figure PCTCN2022117940-appb-000030
antiCD33 VH SEQ ID NO:103
Figure PCTCN2022117940-appb-000031
IL-15 SEQ ID NO:104
Figure PCTCN2022117940-appb-000032
IL-15(L52C)SEQ ID NO:105
Figure PCTCN2022117940-appb-000033
IL-15Ra ECD SEQ ID NO:106
Figure PCTCN2022117940-appb-000034
IL-15Ra Sushi 65 SEQ ID NO:107
Figure PCTCN2022117940-appb-000035
IL-15Ra Sushi 73 SEQ ID NO:108
Figure PCTCN2022117940-appb-000036
IL-15Ra Sushi 77 SEQ ID NO:109
Figure PCTCN2022117940-appb-000037
IL-15Ra Sushi 86 SEQ ID NO:110
Figure PCTCN2022117940-appb-000038
IL-15Ra Sushi 102 SEQ ID NO:111
Figure PCTCN2022117940-appb-000039
IL-15Ra-sushi(S40C):SEQ ID NO:112
Figure PCTCN2022117940-appb-000040
上述IL-15或IL-15Ra的序列均可用于构建本发明的融合蛋白。
如表4所示，设计构建对照抗体antiCD16a antibody、antiCD33 antibody、Elotuzumab、Daratumumab、TAA/CD16A双抗，及根据专利文献US20200148737A1构建CD33/CD16A/IL-15对照分子GTB-3550等分子。
表4对照抗体克隆设计构建
Figure PCTCN2022117940-appb-000041
Figure PCTCN2022117940-appb-000042
Figure PCTCN2022117940-appb-000043
瞬转表达目标分子：
接种ExpiCHO-S细胞到FortiCHO培养基中(Gibco,A1148301)额外加入8mM GlutaMax，37℃，120rpm，8％CO2培养。转染前一天，将ExpiCHO-S细胞密度调整为3*10E6/mL，置于摇床中，37℃，120rpm，8％CO2培养；转染当天，取样，计数，将细胞密度稀释为6*10E6/ml，每瓶40mL，置于125ml的摇瓶中；共转染质粒各20μg与4.8mL Opti MEM混合，加入120μl Polyplus-FectoPRO转染试剂，将DNA和转染试剂混合均匀后，置于室温10min，将混合物缓慢置于细胞中，混合均匀后，置于摇床培养。培养过程中，分别在第1，4，6，8天每瓶补加2mL Feed PFF05(OPM,F81279-001)及1mL的30％葡萄糖溶液。转染第一天，将温度降为32℃，CO2浓度降为5％。13天收样，8000rpm离心20min,取上清，待纯化；
融合蛋白的纯化：
Protein A亲和层析纯化
用平衡液过柱，至少3CV，实际体积20ml，确保最终仪器中流出的溶液pH和电导与平衡液一致，流速1ml/min；将离心后培养液上清过柱，上样40ml，流速0.33ml/min；用平衡液过柱，至少3CV，实际体积20ml，确保最终仪器中流出的溶液pH和电导与平衡液一致，流速0.33ml/min；用洗脱液过柱，UV280上升至15mAU时开始收集洗脱峰(PAC-EP)，UV280下降至15mAU时停止收集，流速1ml/min。样品收集完成后，用pH调节液将PAC-EP调至中性。
CH1-XL亲和层析
将Protein A处理后样品8000rpm×15min离心，取上清；用平衡液过柱，至少3CV，实际体积20ml，确保最终仪器中流出的溶液pH和电导与平衡液一致，流速1ml/min；将离心后上清经上样环过柱，流速0.33ml/min；用平衡液过柱，至少3CV，实际体积20ml，确保最终仪器中流出的溶液pH和电导与平衡液一致，流速0.33ml/min；用洗脱液过柱，UV280上升至10mAU时开始收集洗脱峰(PAC-EP)，UV280下降至10mAU时停止收集，流速1ml/min。样品收集完成后，用pH调节液将CH1-EP调至中性。
实施例2：FACS检测CD33/CD16A/IL-15三功能融合蛋白结合天然表达CD33的HL60细胞
实验目的：人早幼粒白血病细胞株HL60细胞天然表达CD33，本发明通过FACS检测CD33/CD16A/IL-15三功能融合蛋白结合天然表达CD33的HL60细胞
实验方法：HL60细胞于37℃5％CO2培养箱中培养，胰酶消化收集细胞，按100000个细胞每孔接种于96孔板中，2％FBS/PBS冰上封闭1h，孵育不同浓度三功能蛋白及对照蛋白，冰上1h，PBS洗3遍，孵育PE-anti human FC(1：200)稀释，PBS洗3遍，200微升PBS重悬，FACS读取平均荧光值，使用graphpad prism软件分析结果。
如图20所示，CD33/CD16A/IL-15三功能融合蛋白QP743745(FC野生型)、QP43394340(FC进行L234A/L235A突变消除功能)、QP42914285(FC进行L234A/L235A突变消除功能)、CD33/CD16A双特异抗体QP4115777778(FC野生型)、CD33/CD16A双特异抗体QP411543674368(FC进行L234A/L235A突变消除功能)及CD33抗体IgG1wt亚型QP41154116均结合天然表达CD33的HL60细胞。
如图21所示，CD33抗体IgG1wt亚型QP41154116及CD33/CD16A/IL-15三功能融合蛋白均结合天然表达CD33的HL60细胞。
实施例3：FACS检测CD38/CD16A/IL-15三功能融合蛋白结合天然表达CD38的Daudi细胞
实验目的：人Burkitt's淋巴瘤细胞Daudi细胞天然表达CD38，本发明通过FACS检测CD38/CD16A/IL-15三功能融合蛋白结合天然表达CD38的Daudi细胞
实验方法：Daudi细胞于37℃5％CO2培养箱中培养，胰酶消化收集细胞，按100000个细胞每孔接种于96孔板中，2％FBS/PBS冰上封闭1h，孵育不同浓度三功能蛋白及对照蛋白，冰上1h，PBS洗3遍，孵育PE-anti human FC(1：200)稀释，PBS洗3遍，200微升PBS重悬，FACS读取平均荧光值，使用graphpad prism软件分析结果。
如图22所示，CD38抗体IgG1wt亚型QP34503451、CD38/CD16A/IL-15三功能融合蛋白QP43394341(FC进行L234A/L235A突变消除功能)均呈浓度依赖结合天然表达CD38的Daudi细胞。
如图23，图24所示，CD38抗体IgG1wt亚型QP34503451、CD38/CS1/CD16A/IL-15多功能融合蛋白均呈浓度依赖结合天然表达CD38的Daudi细胞。
实施例4：ELISA检测CS1/CD16A/IL-15三功能融合蛋白结合CS1活性
检测试剂：milk(BD,232100),PBS(生工，B548117-0500)；HRP-anti human IgG(H+L)(jackson，109-035-088)；TMB(洛阳佰奥通实验材料中心，C060201)；Elisa板(costa,9018)1×PBS缓冲液：称取NaCl 8.00g、KCl 0.20g、Na2HPO4·12H20 2.9g、KH2PO4 0.2g至800mL ddH2O中溶解，充分溶解后定容至1L，调节pH至7.4，高温灭菌备用。或购买商品化10×、20×的PBS溶液稀释至1×PBS缓冲液使用。封闭液：称取5g的milk至PBS中，封闭液需现配现用。终止液(1mol/LH2SO4)：取109mL 98％的浓H2SO4缓慢滴加至2000mL ddH2O中。TMB 37℃显色10min，置于摇床中(120rpm)，100μl/well。
实验步骤：CS1-FC融合蛋白包板，1μg/ml，4度过夜；PBS洗3遍。按200μL/孔加入封闭液5％milk， 37度孵育1h。封闭结束后，PBS洗3遍，孵育样品，按照20μg/ml 5倍稀释，共稀释7个梯度最后一孔稀释100倍，100μl/well充分混匀后，孵育1h，PBST洗3遍；加酶标抗体：孵育HRP-anti human Fab抗体，按照1:5000稀释比例，100μl/孔，充分混匀后，孵育1h，PBST洗6遍。加底物显色液：按100μL/孔用量加底物显色液TMB，置于摇床中，200rpm,35℃避光显色10min。终止：显色完成后，按100μL/孔用量快速加入终止液终止反应。检测：在酶标仪上，测其A450nm的OD值，使用graphpad prism软件分析结果。
结果如图25所示：CS1/CD16A/IL-15三功能融合蛋白QP7434262(FC野生型)、QP43394342(FC进行L234A/L235A突变消除功能)均呈浓度依赖结合CS1蛋白。
实施例5：Mo7e细胞增殖实验
Mo7e(人巨细胞白血病细胞株)细胞表达IL-15Rβγ，是细胞因子生长依赖性细胞。已有研究表明，静息NK和幼稚T细胞表达中等亲和力IL-15Rβγ表型，细胞因子IL-15/IL-15Ra对Mo7e(IL-15Rβγ)细胞增殖实验结果与对未刺激的PBMC的增殖实验一致(Mol Cancer Ther；11(6)June 2012)。本发明用Mo7e细胞增殖实验评估多功能融合蛋白IL-15活性，方法及结果如下：
实验试剂：Mo7e细胞(人巨细胞白血病细胞株)，购于中国医学科学院基础医学研究所细胞资源中心，细胞增殖及毒性检测试剂盒(CCK-8)，购自美仑生物，货号MA0218；重组人GM-CSF，购自perprotech，货号300-03；人IgG，购自Sigma，货号I4506；其他抗体来自内部制备。
实验方法：Mo7e细胞使用含有10％FBS，2mM L-谷氨酰胺和8ng/ml GM-CSF的RPMI1640培养基于37℃5％CO2培养箱中培养；收集Mo7e细胞，800rpm离心5分钟倒掉上清，细胞用不含有GM-CSF的RPMI1640培养基洗涤2遍；用无GM-CSF的RPMI1640培养基重悬细胞并计数，将细胞按2×10 4个，80μl每孔接种于96孔板中，37℃5％CO2培养箱中培养1小时；将各个待测药用培养基按4倍梯度稀释后，20μl每孔与细胞悬液混合均匀，37℃5％CO2培养箱中培养3天；将CCK-8试剂按10μl每孔加入待测的96孔板中，37℃5％CO2培养箱中孵育4小时；将96孔板取出，于酶标仪中检测450nm波长的吸光值。
图26、图27、图28结果显示，CD33/CD16A/IL-15，CD38/CD16A/IL-15，CS1/CD16A/IL-15三功能融合蛋白均能促进MO7E细胞增殖，证明本发明的三功能融合蛋白分子形式蛋白均有IL-15生物活性。
图29、图30、图31、图32结果显示，CD33/CD16A/IL-15，CD38/CS1/CD16A/IL-15多功能融合蛋白均能促进MO7E细胞增殖，证明本发明的多功能融合蛋白分子形式蛋白均有IL-15生物活性。
实施例6：CD33/CD16A/IL-15三功能融合蛋白介导的ADCC作用
实验目的：通过ADCC实验检测CD33/CD16A/IL-15三功能融合蛋白。
实验材料：PBMC购买自上海赛笠生物科技有限公司，HL60细胞购买自中国科学院细胞库，Cytotox96 non-radioactive cytotoxicity assay检测试剂盒购自Promega(G1780)。
实验步骤：复苏PBMC，收集细胞待第二天备用。准备靶细胞：HL60用胰酶消化，1000rpm 5min。PBS清洗2次后，铺96孔板，20000个每孔，50μl每孔，37度5％CO2孵育2h。准备抗体：用培养基(RPMI1640含10％low-IgG FBS)梯度稀释抗体8个浓度。加入上面稀释各浓度的抗体50μl每孔，37度孵育15min。准备PBMC：将第一天复苏的PBMC离心，用培养基(RPMI1640含10％low-IgG FBS)重悬，计数。按PBMC:Target cell＝20:1或10:1，加入上面的孔板中50μl每孔，37度孵育4小时。LDH检测：对于最大释放组和体积矫正组，提前45min加入10μl裂解液，继续放置培养箱培养。培养4h后，吸取50μl上清至酶标板中，按照Cytotox96 non-radioactive cytotoxicity assay检测试剂盒(Promega，G1780)说明书，加入50μl reagent。室温，避光反应30min后，加入50μl stop solution.490nm吸光值读数(加入stop solution后1h内完成读数)。计算：杀伤百分比＝(样品释放-靶细胞自发-效应细胞自发释放)/(靶细胞最大释放-靶细胞自发释放)*100。将自发释放(对应于在没有抗体的情况下与效应细胞一起温育的靶细胞)定义为0％细胞毒性，并将最大释放(用1％Triton X-100裂解的靶细胞)定义为100％细胞毒性。
图33、图34显示为效靶比10:1的结果，图35为效靶比20:1的结果。结果显示：CD33抗体IgG1wt亚型QP41154116呈浓度依赖引起NK细胞杀伤细胞天然表达CD33的HL60细胞，CD33/CD16A/IL-15三功能融合蛋白QP743745(FC野生型)、QP43394340(FC进行L234A/L235A突变消除功能)、QP42914285(FC进行L234A/L235A突变消除功能)、CD33/CD16A双特异抗体QP4115777778(FC野生型)、CD33/CD16A双特异抗体QP411543674368(FC进行L234A/L235A突变消除功能)引起NK细胞杀伤HL60细胞均优于CD33/CD16A/IL-15三功能融合蛋白对照分子GT-3550(QP877)及CD33抗体IgG1wt亚型QP41154116。CD16A单抗QP43354336及IL-15/IL-15Ra-FC融合蛋白QP33123313均无ADCC效应。
图36、图37、图38显示为效靶比10:1的结果。结果显示：CD33抗体IgG1wt亚型QP41154116呈浓度依赖引起NK细胞杀伤细胞天然表达CD33的HL60细胞，CD33/CD16A/IL-15三功能融合蛋白(FC进行L234A/L235A突变消除功能)引起NK细胞杀伤HL60细胞均优于CD33/CD16A/IL-15三功能融合蛋白对照分子GT-3550(QP877)及CD33抗体IgG1wt亚型QP41154116。CD16A单抗QP43354336及IL-15/IL-15Ra-FC融合蛋白QP33123313均无ADCC效应。
实施例7：CD38/CD16A/IL-15三功能融合蛋白介导的ADCC作用
实验目的：通过ADCC实验检测CD38/CD16A/IL-15三功能融合蛋白。
实验材料：PBMC购买自上海赛笠生物科技有限公司，Daudi细胞购买自中国科学院细胞库， Cytotox96 non-radioactive cytotoxicity assay检测试剂盒购自Promega(G1780)。
实验步骤：复苏PBMC，收集细胞待第二天备用。准备靶细胞：Daudi细胞用胰酶消化，1000rpm5min。PBS清洗2次后，铺96孔板，20000个每孔，50μl每孔，37度5％CO2孵育2h。准备抗体：用培养基(RPMI1640含10％low-IgG FBS)梯度稀释抗体8个浓度。加入上面稀释各浓度的抗体50μl每孔，37度孵育15min。准备PBMC：将第一天复苏的PBMC离心，用培养基(RPMI1640含10％low-IgG FBS)重悬，计数。按PBMC:Target cell＝10:1，或5:1，加入上面的孔板中50μl每孔，37度孵育4小时。LDH检测：对于最大释放组和体积矫正组，提前45min加入10μl裂解液,继续放置培养箱培养。培养4h后，吸取50μl上清至酶标板中,按照Cytotox96 non-radioactive cytotoxicity assay检测试剂盒(Promega，G1780)说明书，加入50μl reagent。室温，避光反应30min后，加入50μl stop solution.490nm吸光值读数(加入stop solution后1h内完成读数)。计算：杀伤百分比＝(样品释放-靶细胞自发-效应细胞自发释放)/(靶细胞最大释放-靶细胞自发释放)*100。将自发释放(对应于在没有抗体的情况下与效应细胞一起温育的靶细胞)定义为0％细胞毒性，并将最大释放(用1％Triton X-100裂解的靶细胞)定义为100％细胞毒性。
图39显示为效靶比10:1的结果，图40为效靶比5:1的结果，如图所示：在不同效靶比下，CD38抗体IgG1wt亚型QP34503451呈浓度依赖引起NK细胞杀伤细胞天然表达CD38的Daudi细胞，CD38/CD16A/IL-15三功能融合蛋白QP43394341(FC进行L234A/L235A突变消除功能)引起NK细胞杀伤Daudi细胞均优于CD38抗体IgG1wt亚型QP34503451。CD16A单抗QP43354336及IL-15/IL-15Ra-FC融合蛋白QP33123313均无ADCC效应。
图41、图42显示为效靶比10:1的结果所示：CD38抗体IgG1wt亚型QP34503451呈浓度依赖引起NK细胞杀伤细胞天然表达CD38的Daudi细胞，CD38/CD16A/IL-15三功能融合蛋白(FC进行L234A/L235A突变消除功能)引起NK细胞杀伤Daudi细胞均优于CD38抗体IgG1wt亚型QP34503451。CD16A单抗QP43354336及IL-15/IL-15Ra-FC融合蛋白QP33123313均无ADCC效应。
实施例8：CD33/CD16A/IL-15三功能融合蛋白介导的ADCP
取健康人外周血单个核细胞(PBMC)分离单核细胞，加入50ng/mL Human Recombinant M-CSF，诱导分化为巨噬细胞。将HL60细胞标记绿色荧光CFSE，将HL60细胞与巨噬细胞按照2:1的比例种96孔板，再加入不同浓度的待检测蛋白。37℃孵育2h后终止反应，再孵育APC anti-human CD11b抗体，通过FACS读数，得到各浓度抗体下APC/FITC双阳性细胞的百分比即为发生吞噬行为的巨噬细胞百分比。
结果如图43所示，CD33/CD16A/IL-15三功能融合蛋白QP743745(FC野生型)及QP43394340(FC进行L234A/L235A突变消除功能)均浓度依赖引起巨噬细胞吞噬HL60细胞。CD33/CD16A/IL-15三功 能融合蛋白对照分子GT-3550(QP877)无ADCP效应。
尽管本发明的内容已经通过上述优选实施例作了详细介绍，但应当认识到上述的描述不应被认为是对本发明的限制。在本领域技术人员阅读了上述内容后，对于本发明的多种修改和替代都将是显而易见的。因此，本发明的保护范围应由所附的权利要求来限定。
Figure PCTCN2022117940-appb-000044
Figure PCTCN2022117940-appb-000045
Figure PCTCN2022117940-appb-000046
Figure PCTCN2022117940-appb-000047
Figure PCTCN2022117940-appb-000048
Figure PCTCN2022117940-appb-000049
Figure PCTCN2022117940-appb-000050
Figure PCTCN2022117940-appb-000051
Figure PCTCN2022117940-appb-000052
Figure PCTCN2022117940-appb-000053
Figure PCTCN2022117940-appb-000054
Figure PCTCN2022117940-appb-000055
Figure PCTCN2022117940-appb-000056
Figure PCTCN2022117940-appb-000057
Figure PCTCN2022117940-appb-000058
Figure PCTCN2022117940-appb-000059
Figure PCTCN2022117940-appb-000060
Figure PCTCN2022117940-appb-000061
Figure PCTCN2022117940-appb-000062
Figure PCTCN2022117940-appb-000063
Figure PCTCN2022117940-appb-000064
Figure PCTCN2022117940-appb-000065
Figure PCTCN2022117940-appb-000066
Figure PCTCN2022117940-appb-000067
Figure PCTCN2022117940-appb-000068
Figure PCTCN2022117940-appb-000069
Figure PCTCN2022117940-appb-000070
Figure PCTCN2022117940-appb-000071
Figure PCTCN2022117940-appb-000072
Figure PCTCN2022117940-appb-000073
Figure PCTCN2022117940-appb-000074
Figure PCTCN2022117940-appb-000075
Figure PCTCN2022117940-appb-000076
Figure PCTCN2022117940-appb-000077
Figure PCTCN2022117940-appb-000078
Figure PCTCN2022117940-appb-000079
Figure PCTCN2022117940-appb-000080
Figure PCTCN2022117940-appb-000081
Figure PCTCN2022117940-appb-000082
Figure PCTCN2022117940-appb-000083
Figure PCTCN2022117940-appb-000084
Figure PCTCN2022117940-appb-000085

Claims (32)

  1. 抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，其特征在于，所述抗原包括肿瘤相关抗原(TAA)；所述三功能融合蛋白包括：特异性结合CD16A的CD16A结合区、特异性结合肿瘤相关抗原(TAA)的TAA结合区、IL-15和IL-15Rα结合形成的IL-15/IL-15Rα复合物、以及Fc结构域。
  2. 根据权利要求1所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，其特征在于，所述CD16A结合区包括抗CD16A抗体或其抗原结合片段，优选的，所述CD16A结合区为靶向CD16A的Fab片段或Fv片段。
  3. 根据权利要求1所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，其特征在于，所述TAA结合区包括抗TAA抗体或其抗原结合片段，优选的，所述TAA结合区为靶向TAA的Fab片段或Fv片段。
  4. 根据权利要求1所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，其特征在于，所述的融合蛋白还包括连接片段；所述连接片段的氨基酸序列优选为若干个GS重复序列。
  5. 根据权利要求1所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，其特征在于，所述融合蛋白包含若干条肽链，所述IL-15和所述IL-15Rα分别位于不同肽链上。
  6. 根据权利要求1所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，其特征在于，所述三功能融合蛋白包括：1个所述的TAA结合区。
  7. 根据权利要求6所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，其特征在于，所述的融合蛋白包括：第一单体和第二单体；其中，
    所述第一单体包括：所述的TAA结合区和第一Fc链；所述第二单体包括：所述的CD16A结合区、所述的IL-15/IL-15Rα复合物和第二Fc链；所述TAA结合区为靶向TAA的Fab片段；所述CD16A结合区为靶向CD16A的Fv片段；
    或者，
    所述第一单体包括：所述的CD16A结合区和第一Fc链；所述第二单体包括：所述的TAA结合区、所述的IL-15/IL-15Rα复合物和第二Fc链；所述CD16A结合区为靶向CD16A的Fab片段；所述TAA结合区为靶向TAA的Fv片段；
    并且，
    所述第一Fc链和所述第二Fc链聚合形成所述的Fc结构域。
  8. 根据权利要求7所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，其特征在于，所述第一单体包括第一肽链和第二肽链，所述第二单体包括第三肽链和第四肽链；
    所述第一肽链包括：TAA结合抗体可变区、抗体恒定区；
    所述第二肽链包括：TAA结合抗体可变区、抗体恒定区；所述第二肽链的抗体恒定区包括第一Fc链；
    所述第三肽链包括：CD16A结合抗体可变区、细胞因子和第二Fc链；
    所述第四肽链包括：CD16A结合抗体可变区、细胞因子；
    所述第一肽链的TAA结合抗体可变区、抗体恒定区，以及所述第二肽链的TAA结合抗体可变区、抗体恒定区的配对区域形成所述的靶向TAA的Fab片段；
    所述第三肽链的CD16A结合抗体可变区和所述第四肽链的CD16A结合抗体可变区配对形成所述的靶向CD16A的Fv片段；
    所述第三肽链的细胞因子和所述第四肽链的细胞因子结合形成所述的IL-15/IL-15Rα复合物。
  9. 根据权利要求7所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，其特征在于，所述第一单体包括第一肽链和第二肽链，所述第二单体包括第三肽链和第四肽链；
    所述第一肽链包括：CD16A结合抗体可变区、抗体恒定区；
    所述第二肽链包括：CD16A结合抗体可变区、抗体恒定区；所述第二肽链的抗体恒定区包括第一Fc链；
    所述第三肽链包括：TAA结合抗体可变区、细胞因子和第二Fc链；
    所述第四肽链包括：TAA结合抗体可变区、细胞因子；
    所述第一肽链的CD16A结合抗体可变区、抗体恒定区，以及所述第二肽链的CD16A结合抗体可变区、抗体恒定区的配对区域形成所述的靶向CD16A的Fab片段；
    所述第三肽链的TAA结合抗体可变区和所述第四肽链的TAA结合抗体可变区配对形成所述的靶向TAA的Fv片段；
    所述第三肽链的细胞因子和所述第四肽链的细胞因子结合形成所述的IL-15/IL-15Rα复合物。
  10. 根据权利要求8或9所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋 白，其特征在于：
    自肽链的N端到C端，所述第三肽链的融合顺序为：抗体可变区～细胞因子～第二Fc链，或为：细胞因子～抗体可变区～第二Fc链；
    自肽链的N端到C端，所述第四肽链的融合顺序为：抗体可变区～细胞因子；或为：细胞因子～抗体可变区；“～”表示连接片段；
    所述抗体可变区为CD16A结合抗体可变区或TAA结合抗体可变区。
  11. 根据权利要求1所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，其特征在于，所述三功能融合蛋白包括：2个所述的TAA结合区。
  12. 根据权利要求11所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，其特征在于，所述的融合蛋白包括：第一单体和第二单体；2个所述的TAA结合区分别为第一TAA结合区和第二TAA结合区；其中，
    所述第一单体包括：所述的第一TAA结合区和第一Fc链；所述第二单体包括：所述的CD16A结合区、所述的第二TAA结合区、所述的IL-15/IL-15Rα复合物和第二Fc链；所述第一TAA结合区为靶向TAA的Fab片段；所述CD16A结合区为靶向CD16A的Fv片段；所述的第二TAA结合区为靶向TAA的Fv片段；
    或者，
    所述第一单体包括：所述第一TAA结合区、所述的CD16A结合区和第一Fc链；所述第二单体包括：所述的第二TAA结合区、所述的IL-15/IL-15Rα复合物和第二Fc链；所述CD16A结合区为靶向CD16A的Fv片段；所述第一TAA结合区和所述所述第二TAA结合区均为靶向TAA的Fv片段；
    并且，
    所述第一Fc链和所述第二Fc链聚合形成所述的Fc结构域。
  13. 根据权利要求12所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，其特征在于，所述第一单体包括第一肽链和第二肽链，所述第二单体包括第三肽链和第四肽链；
    所述第一肽链包括：TAA结合抗体可变区、抗体恒定区；
    所述第二肽链包括：TAA结合抗体可变区、抗体恒定区；所述第二肽链的抗体恒定区包括第一Fc链；
    所述第三肽链包括：TAA结合抗体可变区、CD16A结合抗体可变区、细胞因子和第二Fc链；
    所述第四肽链包括：TAA结合抗体可变区、CD16A结合抗体可变区、细胞因子；
    所述第一肽链的TAA结合抗体可变区、抗体恒定区，以及所述第二肽链的TAA结合抗体可变区、抗体恒定区的配对区域形成所述的第一TAA结合区，所述的第一TAA结合区为靶向TAA的Fab片段；
    所述第三肽链的TAA结合抗体可变区和所述第四肽链的TAA结合抗体可变区配对形成所述的第二TAA结合区，所述的第二TAA结合区为靶向TAA的Fv片段；
    所述第三肽链的CD16A结合抗体可变区和所述第四肽链的CD16A结合抗体可变区配对形成所述的CD16A结合区，所述CD16A结合区为靶向CD16A的Fv片段；
    所述第三肽链的细胞因子和所述第四肽链的细胞因子结合形成所述的IL-15/IL-15Rα复合物。
  14. 根据权利要求13所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，其特征在于：自肽链的N端到C端，所述第三肽链或所述第四肽链的氨基酸片段的融合顺序包括以下任意一种，其中“～”表示连接片段：
    (1)TAA结合抗体可变区～CD16A结合抗体可变区～细胞因子；
    (2)TAA结合抗体可变区～细胞因子～CD16A结合抗体可变区；
    (3)CD16A结合抗体可变区～TAA结合抗体可变区～细胞因子；
    (4)CD16A结合抗体可变区～细胞因子～TAA结合抗体可变区；
    (5)细胞因子～TAA结合抗体可变区～CD16A结合抗体可变区；
    (6)细胞因子～CD16A结合抗体可变区～TAA结合抗体可变区。
  15. 根据权利要求12所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，其特征在于，所述的融合蛋白包括：第一单体和第二单体；其中，
    所述第一肽链包括：TAA结合抗体可变区、CD16A结合抗体可变区和抗体恒定区；
    所述第二肽链包括：TAA结合抗体可变区、CD16A结合抗体可变区、抗体恒定区；所述第二肽链的抗体恒定区包括第一Fc链；
    所述第三肽链包括：TAA结合抗体可变区、细胞因子和第二Fc链；
    所述第四肽链包括：TAA结合抗体可变区、细胞因子；
    所述第一肽链的TAA结合抗体可变区和所述第二肽链的TAA结合抗体可变区配对形成所述的第一TAA结合区，所述的第一TAA结合区为靶向TAA的Fv片段；
    所述第一肽链的CD16A结合抗体可变区和所述第二肽链的CD16A结合抗体可变 区配对形成所述的CD16A结合区，所述CD16A结合区为靶向CD16A的Fv片段；
    所述第三肽链的TAA结合抗体可变区和所述第四肽链的TAA结合抗体可变区配对形成所述的第二TAA结合区，所述的第二TAA结合区为靶向TAA的Fv片段；
    所述第三肽链的细胞因子和所述第四肽链的细胞因子结合形成所述的IL-15/IL-15Rα复合物。
  16. 根据权利要求15所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，其特征在于：
    在所述第一肽链或所述第二肽链中，自肽链的N端到C端，所述TAA结合抗体可变区和所述CD16A结合抗体可变区的融合顺序为：TAA结合抗体可变区～CD16A结合抗体可变区，或CD16A结合抗体可变区～TAA结合抗体可变区；“～”表示连接片段；或者，
    在所述第三肽链或所述第四肽链中，自肽链的N端到C端，所述TAA结合抗体可变区和所述细胞因子的融合顺序为：TAA结合抗体可变区～细胞因子，或细胞因子～TAA结合抗体可变区。
  17. 根据权利要求8或9或13至16中任意一项所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，其特征在于，所述TAA结合抗体可变区选自靶向TAA的VH结构域或VL结构域，所述CD16A结合抗体可变区选自靶向CD16A的VH结构域或VL结构域，所述的细胞因子选自IL-15或IL-15Rα；所述的抗体恒定区包括CL结构域或CH1结构域。
  18. 根据权利要求17所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，其特征在于，所述的VH结构域和VL结构域之间具有一对或多对二硫键，并且包含以下突变组合形式的任意一种以上，根据EU计数：
    Figure PCTCN2022117940-appb-100001
    Figure PCTCN2022117940-appb-100002
  19. 根据权利要求1所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，其特征在于，所述IL-15包括：IL-15及其能结合IL-15Ra的突变，截短及各种衍生物；所述IL-15Ra包括：IL-15Ra及其能结合IL-15的突变，截短及各种衍生物；优选地，所述IL-15包括但不限于以下任意一组合所示的突变方式，计数方式根据IL-15的氨基酸序列的第一个氨基酸开始算为第1位；
    组合 IL-15突变 1 N1D 2 N4D 3 D8N 4 D30N 5 D61N 6 E64Q 7 N65D 8 Q108E 9 N1D/D61N 10 N1D/E64Q 11 N4D/D61N 12 N4D/E64Q 13 D8N/D61N 14 D8N/E64Q 15 D61N/E64Q 16 E64Q/Q108E 17 N1D/N4D/D8N 18 D61N/E64Q/N65D 19 N1D/D61N/E64Q/Q108E 20 N4D/D61N/E64Q/Q108E 21 D30N/E64Q/N65D
    ；
    或者，所述IL-15/IL-15Ra复合物包括但不限于以下任意一组合所示的突变方式，计数方式根据IL-15或IL-15Ra的氨基酸序列的第一个氨基酸开始算为第1位；
    组合 IL15 IL15Ra 1 wt D96 2 wt D96/P97 3 wt D96/P97/A98 4 E87C D96/C97 5 E87C D96/P97/C98 6 E87C D96/C97/A98 7 V49C S40C 8 L52C S40C 9 E89C K34C 10 Q48C G38C 11 E53C L42C 12 C42S A37C 13 L45C G38C 14 L45C A37C
    。
  20. 根据权利要求1所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，其特征在于，所述TAA选自CD20、CD19、CD30、CD33、CD38、CD40、CD52、slamf7、GD2、CD24、CD47、CD133、CD217、CD239、CD274、CD276、CEA、Epcam、Trop2、TAG72、MUC1、MUC16、mesothelin、folr1、CLDN18.2、EGFR、EGFR VIII、C-MET、HER2、FGFR2、FGFR3、PSMA、PSCA、EphA2、ADAM17、17-A1、NKG2D ligands、MCSP、LGR5、SSEA3、SLC34A2、BCMA、GPNMB、CCR4、VEGFR-2、CD6、整合素α4、PDGFRα、NeuGcGM3、整合素αVβ3、CD51、CTAA16.88、CD22、ROR1、CSPG4、SS1或IGFR1。
  21. 根据权利要求1所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，其特征在于，所述Fc结构域选自Human IgG1 Fc、Human IgG2 Fc、Human IgG3 Fc、Human IgG4 Fc或其变异体，优选自IgG1 Fc、或Human IgG4 Fc或其变异体；所述Fc结构域为Fc异源二聚体形式；优选地，所述Fc异源二聚体包含但不限于以下突变的组合，以下突变为根据EU计数：
    Figure PCTCN2022117940-appb-100003
  22. 根据权利要求1所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，其特征在于，所述Fc结构域选择消除免疫效应功能，优选包含以下任一突变方式，以下突变为根据EU计数：
    Figure PCTCN2022117940-appb-100004
  23. 根据权利要求7或12所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，其特征在于，所述第一Fc链不结合protein A，优选包括突变H435R或H435R/Y436F，根据EU计数；所述第二Fc链能够结合protein A。
  24. 根据权利要求1所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，其特征在于，所述CD16A结合区包括序列如SEQ ID NO:97所示的VH结构域和SEQ ID NO:96所示的VL结构域；或者，所述IL-15的序列如SEQ ID NO:104或105所示；或者，所述IL-15Ra的序列如SEQ ID NO:106至112中任意一项所示；优选的，所述CD16A结合区的VH和VL之间，和/或所述IL-15与IL-15Ra之间，至少具有一对以上二硫键。
  25. 根据权利要求1所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，其特征在于，由以下任意一组序列所示或与其具有90％以上同一性的氨基酸片段融合得到：
    (1)SEQ ID NO:01、02、03、04；
    (2)SEQ ID NO:01、05、03、06；
    (3)SEQ ID NO:07、08、09、10；
    (4)SEQ ID NO:01、02、11、12；
    (5)SEQ ID NO:01、02、13、14；
    (6)SEQ ID NO:01、05、11、15；
    (7)SEQ ID NO:01、05、13、16；
    (8)SEQ ID NO:38、39、40、41；
    (9)SEQ ID NO:38、39、42、43；
    (10)SEQ ID NO:38、39、44、45；
    (11)SEQ ID NO:38、39、46、47；
    (12)SEQ ID NO:48、49、50、51；
    (13)SEQ ID NO:48、49、52、53；
    (14)SEQ ID NO:48、49、54、55；
    (15)SEQ ID NO:48、49、56、57；
    (16)SEQ ID NO:58、59、60、61；
    (17)SEQ ID NO:58、59、62、63；
    (18)SEQ ID NO:58、59、64、65；
    (19)SEQ ID NO:58、59、66、67；
    (20)SEQ ID NO:68、69、70、71；
    (21)SEQ ID NO:72、73、70、71；
    (22)SEQ ID NO:74、75、70、71；
    (23)SEQ ID NO:76、77、70、71；
    (24)SEQ ID NO:78、79、70、71；
    (25)SEQ ID NO:38、39、80、81；
    (26)SEQ ID NO:38、39、82、83；
    (27)SEQ ID NO:38、39、84、85；
    (28)SEQ ID NO:38、39、86、87；
    (29)SEQ ID NO:38、39、88、89；
    (30)SEQ ID NO:38、39、90、91；
    (31)SEQ ID NO:38、39、92、93；
    (32)SEQ ID NO:38、39、94、95。
  26. 根据权利要求1所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，其特征在于，所述抗原还包括：传染性疾病相关抗原、病原体、免疫功能相关抗原。
  27. 一种核酸分子，其特征在于，其编码权利要求1至26中任意一项所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白。
  28. 一种药物组合物，其特征在于，含有权利要求1至26中任意一项所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白，以及药学上可接受的载体。
  29. 权利要求1至26中任意一项所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白在制备用于抑制或治疗癌症、感染和免疫调节疾病的药物中的应用。
  30. 根据权利要求29所述的应用，其特征在于，所述癌症包括前列腺癌、肺癌、结肠癌、直肠癌、膀胱癌、黑色素瘤、肾癌、口腔癌、咽癌、胰腺癌、子宫癌、甲状腺癌、皮肤癌、头颈癌、宫颈癌、卵巢癌或血液系统癌症。
  31. 一种蛋白的复合单元，其特征在于，所述复合单元包括：权利要求8所述的抗原靶向、抗CD16A和免疫效应细胞激活三功能融合蛋白中的第三肽链的CD16A结合抗体可变区和细胞因子、第四肽链的CD16A结合抗体可变区和细胞因子，以及若干连接片段；
    所述第三肽链的CD16A结合抗体可变区通过连接片段与所述第三肽链的细胞因子融合；所述第四肽链的CD16A结合抗体可变区通过连接片段与所述第四肽链的细胞因子融合；
    所述第三肽链的CD16A结合抗体可变区和所述第四肽链的CD16A结合抗体可变区选自靶向CD16A的VH结构域或VL结构域，并配对形成Fv片段；
    所述第三肽链的细胞因子和所述第四肽链的细胞因子选自IL15或IL15Rα，并结合形成IL-15/IL-15R复合物；
    优选的，所述VH结构域和VL结构域之间，和/或所述IL15和IL15Rα之间，具有一对以上的二硫键。
  32. 一种核酸分子，其特征在于，其编码权利要求31所述的蛋白的复合单元。
PCT/CN2022/117940 2021-09-09 2022-09-08 抗原靶向、抗cd16a和免疫效应细胞激活三功能融合蛋白及其应用 Ceased WO2023036270A1 (zh)

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