Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K14/00—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof
  • C07K14/195—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from bacteria
  • C07K14/24—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from bacteria from Enterobacteriaceae (F), e.g. Citrobacter, Serratia, Proteus, Providencia, Morganella, Yersinia
  • C07K14/245—Escherichia (G)
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
  • A61P31/04—Antibacterial agents
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K14/00—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof
  • C07K14/195—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from bacteria
  • C07K14/24—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from bacteria from Enterobacteriaceae (F), e.g. Citrobacter, Serratia, Proteus, Providencia, Morganella, Yersinia
  • C07K14/25—Shigella (G)
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K39/00—Medicinal preparations containing antigens or antibodies
  • A61K2039/51—Medicinal preparations containing antigens or antibodies comprising whole cells, viruses or DNA/RNA
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K39/00—Medicinal preparations containing antigens or antibodies
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K2319/00—Fusion polypeptide

Definitions

• the invention relates to a family of multi-unit bacterial proteins that are associated with hemorrhagic colitis and the life-threatening sequela, hemolytic uremic syndrome. These proteins, defined as members of the "Shiga toxin family,” have been tagged with histidine residues.
• the invention further relates to a non-toxinogenic but immunoreactive form of histidine-tagged Shiga toxins, or toxoids.
• the invention relates to fusion proteins obtained by combining histidine-tagged Shiga toxins or toxoids with other proteins. Histidine tagging greatly facilitates purification of Shiga toxins, and the invention also relates to methods for purifying such toxins.
• the invention further relates to using the histidine-tagged Shiga toxoids or fusion proteins of Shiga toxoids as antigens for generating an immune response against infection or transmission by bacteria expressing Shiga toxin. It also relates to antibodies to Shiga toxins, toxoids, or Shiga toxin/toxoid fusion proteins, both monoclonal and polyclonal, and their use in treating, diagnosing, and preventing of disease and infections by pathogenic E. coli. Finally, the invention relates to preparing the Shiga toxins, toxoids, and fusion proteins. BACKGROUND OF THE INVENTION
• EHEC Enterohemorrhagic Escherichia coli
• HC bloody diarrhea
• HUS hemolytic uremic syndrome
• HC and HUS are transmitted by the ingestion of contaminated food, particularly undercooked beef products, such as hamburger.
• contaminated food particularly undercooked beef products, such as hamburger.
• undercooked beef products such as hamburger.
• HC and HUS appear to be mediated by the toxin produced by EHEC and Shigella dysenteriae (for review see O'Brien and Holmes, Microbiol. Rev., 51: 206-220 (1987)).
• Shiga toxins (alternatively, “verotoxins”) have cytotoxic, neurotoxic, and enterotoxic activity (Strockbine, ⁇ . et al., "Two toxin- converting phages from Escheria coli 0157:H7 strain 933 encode antigenically distinct toxins with similar biological activities," Infect. Immun., 53:135-140 (1986)). Based on their immunological cross-reactivity, the Shiga toxins have been divided into two groups. (Strockbine et al., supra).
• Stxl Shiga toxin type 1
• Stx2 Shiga toxin type 2
• Stx2e Stx2e
• Stx2c Stx2vha
• Stx2vhb Stx2vhb
• Shiga toxin encompasses Shiga toxin and any other toxins in the Stxl or Stx2 group.
• Stx will refer to the protein designation, and the abbreviation “stx” to the gene designation.
• the A subunit gene encodes the enzymatically active subunit.
• the A subunit polypeptide has two functional domains, Al and A2, which are linked by a disulfide bond.
• the Al portion is an N-glycosidase that acts on the 28S rRNA subunit of eukaryotic ribosomes to inhibit protein synthesis.
• Talina, S. et al., "Shiga toxin, Shiga-like toxin II variant, and ricin are all single-site RNA N-glycosidases of 28S RNA when microinjected into Xenopus oocytes," J. Biol.
• the A2 fragment is required for the binding of 5 B subunit polypeptides.
• the pentamer of B subunits is responsible for binding to a receptor on eukaryotic cells.
• a polypeptide containing the entire A subunit and B subunit pentameter is referred to as a Shiga holotoxin.
• progress in the search for such agents has been hampered by the lack of a fast and simple method for purifying Shiga toxins. Therefore, the need exists for such a fast and simple method.
• the need also exists for such a method that allows for large-scale production of Shiga toxoids and fusion proteins of Shiga toxins and toxoids.
• Such a method should simplify obtaining antibodies against Shiga toxin and vaccines against HC and HUS using Shiga toxoids and fusions of Shiga toxoids.
• the present invention describes the isolation and purification of biologically and immunologically active histidine-tagged Shiga toxins (His-tagged), a toxin associated with HC and the potentially life-threatening disease HUS transmitted by strains of pathogenic bacteria.
• His-tagged histidine-tagged Shiga toxins
• HUS potentially life-threatening disease
• One aspect of the invention is obtaining and using Shiga toxoids that are immunoreactive but not toxic.
• the invention describes using such obtained Shiga toxoids in vaccines against HC and HUS.
• Another aspect of the invention is obtaining and using fusion proteins of His- tagged Shiga toxins or toxoids. These fusion proteins have the advantage of combining beneficial properties of each protein, resulting, for example, in improved protein stability or targeted delivery of a his-tagged Shiga therapeutic agent.
• Yet another aspect of the invention is obtaining and using antibodies to His- tagged Shiga toxins, toxoids, or Shiga toxin/toxoid fusion proteins.
• These antibodies can be either monoclonal or polyclonal and have potential uses in treating, diagnosing, or preventing HC and HUS caused by EHEC or Shigella dysenteriae type 1 infections.
• Other aspects of the present invention will become apparent from the more detailed description provided below, to be read in conjunction with the accompanying drawings.
• Figure 1 depicts the protein structure of Shiga toxin genes.
• Figure 2 depicts the predicted amino acid sequence for the mature A subunit and the unprocessed B subunit of Stxl. (Calderwood et al., Proc. Natl. Acad. Sci. USA, 84: 4364-4368 (1987); DeGrandis et al., J. BacterioL, 169:4313-4319(1987)).
• Figure 3 depicts the predicted amino acid sequence for the mature A subunit and the unprocessed B subunit of Stx2. (Jackson et al., FEMS Lett., 44:109-1 14 (1987)).
• Figure 4 depicts the predicted DNA sequence for stxl and DNA upstream of that sequence.
• Figure 5 depicts the predicted DNA sequence for stx2 and DNA upstream of that sequence. (Jackson et al., FEMS Lett., 44: 109-1 14 (1987)).
• Figure 6 depicts the approximately 1200 base pair fragments of stxl produced by PCR amplification.
• Figures 6a-c depict the fragments used to make plasmids pQHI, pQHEl, and p7HI, respectively.
• Nucleotides in lower case represent non-toxin sequences in the primers and/or base changes.
• Figure 7 depicts the approximately 1200 base pair fragments of stx2 produced by PCR amplification.
• Figures 7a and 7b depict the fragments used to make plasmids pQHI and pQHEII, respectively.
• Nucleotides in lower case represent non-toxin sequences in the primers and/or base changes.
• Figure 8 depicts the plasmid pQHI, encoding the His-Stx 1 fusion and driven by the T5 promoter.
• Figure 9 depicts the plasmid pQHII, encoding the His-Stx 2 fusion and driven by the T5 promoter.
• Figure 10 depicts the plasmid pQHEI, encoding the His-Enterokinase site-Stxl fusion and driven by the T5 promoter.
• Figure 11 depicts the plasmid pQHEII, encoding the His-Enterokinase site-Stx 2 fusion and driven by the T5 promoter.
• Figure 12 depicts the plasmid pQHIIvhb, encoding the His-Stx 2 fusion and driven by the T5 promoter.
• Figure 13 depicts the plasmid pQHEIIvhb, encoding the His-Enterokinase site- Stx 2 fusion and driven by the T5 promoter.
• Figure 14 depicts the plasmid p7HI, encoding the His-Stx 1 fusion and driven by the PT7 promoter.
• Figure 15 depicts the plasmid p7HII, encoding the His-Stx 2 fusion and driven by the PT7 promoter.
• Figure 16 depicts the expression of His-Stx fusion proteins according to the invention.
• An object of the invention is to purify large quantities of Shiga toxins that retain their biological and immunological properties.
• a Shiga toxin gene was cloned into a Histidine-tag expression vector, expressed, and purified.
• An additional object of the invention is to obtain antigens specific to Shiga toxoids.
• a toxin that is non-toxinogenic but immunoreactive for generating an immune response against Shiga toxins.
• Another object of the invention is the creation of antibodies against Shiga toxins or toxoids for treating, diagnosing, or preventing disease and infections by pathogenic bacteria.
• the his-tagged Shiga toxins or toxoids described above can be used for these purposes.
• the size of the his-tagged Shiga toxin to be used may be varied according to the specific purpose for the Shiga toxin. For example, if the purpose is fusing the his-tagged Shiga toxin or toxoid with one or more proteins, a smaller fragment might be selected to enhance stability of the combined fusion product, although using a larger fragment is by no means precluded.
• the desired size of the His-Shiga toxin may also vary with the convenience of the available restriction sites, in light of the materials and methods known to those skilled in the art.
• His-Shiga toxin or “His-tagged Shiga Toxin” refers to the fragment of about 372-377 amino acids comprising the A and B subunits of any of the Shiga toxin family members fused with a histidine tag. Smaller fragments that retain biological and/or immunological function are also included. Biological function is measured by, for example, cytotoxicity to Vero cells, as described in Example III.A. Immunological function may also be tested by, for example, neutralization by specific antisera, as described in Example III.B.
• a preferred embodiment of the invention is a His-Tagged Shiga holotoxin, containing 1 A subunit and 5 B subunits.
• the tag consists of six histidine residues.
• the most preferred embodiment is a His 6 -Tagged Shiga holotoxin.
• One of the objects of the present invention is to administer His-Shiga toxoids to protect against illness or disease caused by EHEC or Shigella dysenteria type I, such as HC and HUS. The object is achieved through the stimulation of immune response directed against Shiga toxins.
• immunizing or “immunization” is used in the application.
• the degree of protection achieved by such immunization will vary with the degree of homology between Shiga toxins and the His-Shiga toxoids, as well as other factors, such as unique attributes of the patient or the species treated.
• immunization is not limited to avoiding infection altogether; it also includes decreasing the severity of the infection, as measured by the following indicators: reduced incidence of death, HUS, or permanent kidney damage; decreased levels of toxin; reduced fluid loss; or other indicators of illness regularly used by those skilled in the relevant art.
• His-Tagged Shiga toxins have the biological and immunological properties of Shiga toxins, they may be used for any application appropriate for Shiga toxins.
• Stxl can be used to treat bone marrow cells from mice with human B-cell lymphomas. The Shiga toxin bound to the receptor on the lymphoma cell and the toxin killed the cancer cell. (LaCasse et al., Blood 88:1551(1996)).
• His-Shiga toxins or fusions could be used for the same purpose and in the same manner. Isolating and Purifying His-Tagged Shiga Toxin
• the standard protocol for purification of Shiga toxin comprising A and B subunits uses biochemical techniques.
• the standard protocol was developed by O'Brien et al. (O'Brien et al., Infect. Immun. 40:675 (1983); O'Brien et al., Infect. Immun., 30: 170( 1980)).
• the method employs four purification steps: 1 ) ammonium sulfate precipitation; 2) DEAE Sepharose column chromotography; 3) chromatofocusing; and 4) antibody affinity chromotography.
• This method has the advantages of employing publicly available materials, being capable of purifying all Shiga toxins, and being capable of purifying Shiga toxins for human use. Its disadvantage is that the minimum time required for this test is three weeks.
• the Shiga toxin gene or portions of the Shiga toxin gene have been cloned and expressed in bacteria and purified.
• Downes et al., Infect. Immun. 56:1929 (1988) expressed the stx2 gene in bacteria and purified Stx2.
• the purification methods following expression were essentially those of the standard method or hydatid cyst method and, therefore, had the same disadvantages.
• His-Tagging of proteins is known, it was not expected that His- Tagging of a Shiga toxin would be successful. The skilled artisan would have believed that a His-Shiga toxin fusion would have lost cytotoxicity, because the skilled artisan would have expected that the attachment of a His-Tag to the amino acid terminus of a toxin would destroy its activity. Moreover, the multi-unit toxin would have been expected to be more susceptible to losing toxicity upon fusion with additional amino acids, since it is known that the toxin must retain its conformation for enzymatic activity and for binding of the B subunits to cell receptors, and the addition of amino acids would have been expected to destroy proper conformation.
• the His-Stx fusion clones were generated by PCR amplification of stx operons, restriction enzyme digestion of the PCR products, .and ligation of the fragments in- frame into the appropriate vectors.
• the expression vectors and primers were used to place histidine residues at the amino acid terminus of the toxins and place the constructs under the control of either an IPTG-inducible promoter (pQE vectors) (Qiagen, Inc., 9600 DeSoto Avenue, Chatsworth, CA 9131 1 , 1 -800-362-7737) or a T7 promoter (pt7-7) (Tabor et al., Proc. Natl. Acad. Sci. 82: 1074 (1985)).
• pQE vectors IPTG-inducible promoter
• pt7-7-7 T7 promoter
• Bacterial strains and plasmids The bacterial strains and plasmids used in this study are shown in Table 1. Table 1. Bacterial strains and plasmids used in this study.
• the Shiga toxin genes are cloned using polymerase chain reaction (PCR), a standard technique in the art. Primers were designed to amplify the stx toxin operons beginning at the first codon of the mature A subunit gene and ending downstream of the termination codon of the B subunit gene and created using standard techniques. The primers contained recognition sequences to generate unique restriction sites at the ends of the toxin operon. In a preferred embodiment, the 5' primers also contained sequences to encode the recognition sequence of the protease enterokinase to allow for removal of the histidine residues. The primers used are shown in Table 2. TABLE 2. Primers used.
• Sequences encoding stx toxins were amplified from toxin clones using a PCR kit (GeneAmp kit, Perkin-Elmer Cetus, Norwalk, CT), which was used according to the manufacturer's instructions.
• the resulting stx PCR products were approximately 1200 bp are shown in Figures 6a, 6b, 6c, 7a, and 7b.
• the DNA products contain the coding sequences for the mature A subunit and the unprocessed B subunit.
• Plasmid DNA was isolated by the method of
• PCR Reactions and ligations were summarized in Table 3. TABLE 3: PCR Reactions and ligations.
• Plasmid pJES120 was the template with primers IIEC and IIH3 in a PCR reaction for amplification of the stx2 operon.
• the resulting PCR product started with the first codon of the mature A subunit gene, extended through the A subunit gene, the complete B subunit gene, and ended just downstream of the terminate codon of the B subunit gene ( Figure 6b).
• the PCR product was digested with the restriction endonucleases Bam HI and Hind III, as was the vector plasmid pQE30.
• the vector pQE30 was chosen because ligation of the PCR product with pQE30 at the Ba Hl sites would result in an in-frame protein fusion of the 6 histidine residues, the enterokinase cleavage site, additional amino acids, and the +1 residue of the mature A subunit.
• the digested PCR product was ligated into the digested vector pQE30.
• the ligation reaction was transformed into strain XL 1 -Blue and plated on agar that contained ampicillin. Colonies were screened for the presence of a plasmid that contained an approximately 1200 bp BamHI/HindHI DNA insert.
• His-Shiga toxin was purified under nondenaturing conditions because of the multi-subunit nature of the Shiga toxins.
• the strain was streaked onto a selective agar plate and incubated at 37°C for 18-24 hrs. A 20 ml overnight culture was then prepared from a colony. The saturated culture was then diluted 1/50 into one liter of L broth with antibiotics and the culture was grown at 37°C until it reached an O.D. 60 ⁇ of 0.7-0.9. IPTG (2mM final concentration) was then added to induce expression of the His 6 tagged toxin and the culture was grown for an additional 5 hrs. Cells were pelleted and the pellet was kept at -70°C overnight.
• the pellet was resuspended in sonication buffer (50 mM sodium phosphate (pH 8.0), 300 mM sodium chloride, 20 mM imidazole, 30 ⁇ g/ml PMSF), and the cells were sonicated to release toxin.
• sonication buffer 50 mM sodium phosphate (pH 8.0), 300 mM sodium chloride, 20 mM imidazole, 30 ⁇ g/ml PMSF
• the cells were sonicated to release toxin.
• the cells were treated with polymixin-B (2 mg/ml final concentration) for 3 hrs at 4°C.
• the extracts were clarified by centrifugation and filtered through a milipore 0.45 ⁇ m filter.
• Ni-NTA nickel-nitrilotriacetic acid ligand
• Fractions were tested for cytotoxicity on Vero cells (as explained in Example III) and were subjected to SDS-PAGE and silver stain. Fractions that were highly cytotoxic and relatively clean were pooled and dialyzed against sonication buffer. This pool was then placed onto a Ni-NTA spin column (Qiagen) to further purify the His 6 - toxin and the resulting two fractions were dialyzed against PBS. A final cytotoxicity assay and BCA protein assay were performed for the determination of the specific activity of the purified toxin.
• the protocol described above is modification of the non-denaturing protocol described by Qiagen to purify His-tagged proteins.
• the toxin that eluted contained many contaminants.
• modifications were made. Specifically, Tween-20 was added to the wash buffer, and the pH of the wash buffer was adjusted to 8. Also, a final Ni-NTA spin column was added.
• This one-step His-affinity method for purifying His-Shiga toxin by an Ni-NTA column has several advantages over existing methods, as summarized in Table 4. TABLE 4. Comparison of Toxin Purification Techniques
• the Ni-NTA one-step method is superior because of its relative speed and simplicity. It requires a minimum of one week as opposed to a minimum of two or more weeks. Moreover, all of the materials are readily available, the method is not limited to Shiga toxins that bind Plgp, and the products are suitable for use in humans.
• the Shiga toxin obtained by the method has many uses.
• the His- Shiga toxin may be used as a positive control antigen in a Shiga toxin detection kit. Such kits will use a purified His-Shiga toxin as positive indicator for the toxin in a sample. Other uses are detailed in the Examples below.
• Example III Verifying Biological and Immunological Activity of His-Shiga Toxins
• A. Vero Cell Cytotoxicity Assay The cytotoxicity of His-Shiga toxins obtained according to the methods described in Examples 1 and II was verified by determining their cytotoxicity for Vcro cells. Cytotoxicity assays on strains that expressed His-Shiga toxins were done essentially as described by Gentry and Dalrymple, J Clin. Microbiol, 12: 361-366 (1980). Briefly, cultures induced for the expression of His-Shiga toxins were disrupted by sonic lysis and clarified by centrifugation. The extracts were serially diluted in tissue culture medium (Dulbecco modified Eagle medium containing 10% fetal calf serum, 0.8 mM glutamine, 500 U of penicillin G per ml. and 500 mg of streptomycin per ml).
• tissue culture medium Dulbecco modified Eagle medium containing 10% fetal calf serum, 0.8 mM glutamine, 500 U of penicillin G per ml. and 500 mg of streptomycin per ml.
• microtiter plate wells containing about 10 4 Vero cells were added to microtiter plate wells containing about 10 4 Vero cells in 100 ⁇ l of medium.
• the tissue culture cells were incubated at 37°C in 5% CO 2 for 48 hours and then fixed and stained with crystal violet. The intensity of color of the fixed and stained cells was measured with a Titertek reader at 620 nm.
• His-Shiga toxins obtained according to the methods described in Examples I and II were tested for antisera neutralization. Neutralization of cytoxic activity was described in great detail in Schmitt et al., Infect, and Immun., 59:1065-1073 (1991).
• the His-Shiga toxin could be fused with another protein of interest. These methods include chemical and genetic methods, as in cloning and expressing a fusion protein, although one skilled other methods arc readily apparent to one skilled in the art. (D.V. Goeddell, Meth Enzymol. Vol. 185(1990); Itakura, Science 198:1056 (1977)). For example, if a combination vaccine for immunization against Shiga toxin and another toxin (protein X) is desired, then these two toxins can be fused into a single protein. This can be achieved by first cloning the codons for the histidine residues in frame to the coding region of protein X.
• the fragment containing His-Protein X is then subcloned in-frame of the Shiga toxin operon.
• the fragment is subcloned in-frame to the A2-B portions of the Shiga toxin operon.
• the resulting His-Protein X-A2-B5 fusion would ideally result in immunization against Shiga toxin and protein X.
• Haptens and antigens may derive from but are not limited to bacteria, rickettsiae, fungi, viruses, parasites, drugs, or chemicals. They may include, for example, small molecules such as peptides, oligosaccarides, and toxins. Certain antimicrobial drugs, chemotherapeutic drugs having the capacity of being absorbed into the intestine may also be coupled to Shiga toxin for targeted delivery, since the B subunit pentamer binds to receptors in the intestine. Conjugation methods are well known in the art.
• Conjugation may be achieved by genetically fusing His-Shiga toxoids by standard molecular techniques or by conjugation to a polysaccharide. Methods of conjugation include those outlined in M. Brunswick et al., J. Immunol, 140:3364 (1988) and Chemistry of Protein Conjugates and Crosslinking, CRC Press, Boston (1991). Coupling of Shiga toxids to other proteins or polysaccharides would prevent disease from additional pathogens.
• a form of Shiga toxin that is immunoreactive but not toxinogenic is needed for immunization in animals.
• Such a His-Shiga toxoid can be generated using chemical or genetic methods.
• the chemical method involves treating the His-Shiga toxin with either formaldehyde or glutaraldehyde, as described by Perera et al., JClin. Microbiol. 26:2127 (1988)). Briefly, samples of toxin containing 100 ⁇ g of protein are treated for 3 days at 37°C with 0.1 M Na 2 HPO 4 (pH 8.0) containing 1% formaldehyde, and the residual formaldehyde is removed by dialysis against phosphate-buffered saline (PBS).
• PBS phosphate-buffered saline
• a toxoid may be produced by site-directed mutagenesis. as described in Gordon et al., Infect. Immun. 60:485 (1992); Hovde et al., Proc. N ⁇ tl. Ac ⁇ d. Sci. 85:2568 (1988); Jackson et al., J. B ⁇ cteriol. 172: 3346-3350 (1990).
• Several methods and kits exist for site-directed mutagenesis of a gene employs the Bio-Rad Muta-Gene in vitro mutagenesis kit. Oligonucleotides can be designed and synthesized which alter specific condons in the toxin genes. Uracil- incorporated, single-stranded target plasmid DNA will be mutagenized according to the directions supplied by the manufacturer of the mutagenesis kit. The nucleotide changes are then confirmed by DNA sequence analysis.
• a subunit targets are the residues El 67 and E170.
• the Shiga toxoid resulting from this mutation has been used for vaccinating pigs. (Gordon et al., supra).
• Antisera specific for Shiga toxins are required to treat and prevent potentially- deadly infections by EHEC and Shigella dysenteriae type I. Specifically, once a child becomes infected, the child and his or her family members or children in his or her day care group can receive anti His-Shiga toxin sera to achieve a protective immune response.
• a protective immune response is one that elicits sufficient antibody to permit a patient to avoid infection, decrease the significance or severity of an infection, or decrease the ability of bacteria to colonize the gastrointestinal tract.
• His-Shiga toxoid obtained by the methods described in Example VI, can be administered to a mammal, such as a horse intraperitoneally.
• a mammal such as a horse intraperitoneally.
• the horse is used to produce serum against botulism toxin for administration to humans, Hibbs et al., Clin. Infect Dis., 23:337-40 (1996), and the horse would be a preferred method for producing shiga toxin antiserum.
• the serum of the immunized horse or other mammal
• a large amount of serum can be quickly made using this method.
• patients must first be screened for an immune reaction to horse serum.
• a small amount of horse serum would be subcutaneously injected, and the patient would be monitored for a reaction.
• Such methods for administering horse antiserum against toxins to humans are well known to the skilled artisan. Hibbs et al., supra; Dehesa and Possani, Toxicon, 32: 1015-1018(1994); Gilan ct al., Toxicon, 27:1 105-1 1 12 (1989).
• the His-Shiga toxoid can be administered to human volunteers, either intraperitoneally or orally.
• the plasma from these volunteers is then isolated, and the human anli-His-Shiga toxin serum can be administered to patients. No threat of serum sickness arises from this method.
• Human hyperimmune globulin to Hemophilus influenzae b, Streptococcus pneumoniae, and Neisseria meningitidis has previously been prepared by others (Siber et al., Infect, and Immun., 45: 248-254 (1984)).
• B. Vaccines against Shiga Toxins An embodiment of the invention is vaccines against Shiga toxin infection.
• these vaccines can include antibodies directed against His-Shiga toxin, obtained further described in Example VII.
• these vaccines can be combination vaccines that comprise His-Shiga toxoid fused or conjugated with another protein, hapten, or antigen, as described in Example IV. These vaccines can be administered intraperitoneally or injectably by methods well known in the art.
• a preferred method of administering His-Shiga toxin or toxoid and fusions thereof is by further conjugation to Synsorb® (SynSorb Biotech, Inc., 1204 Kensington Road, N.W., Calgary, Alberta, Canada, T2N3P5.)
• Synosorb is a sand-like material to which Shiga toxin receptor (Gb3) is covalently bound (Armstrong et al., J. Infect. Dis., 171 : 1042 (1995)). This compound has been shown to bind Shiga toxins and appears to be safe for human ingestion. (Armstrong et al., supra)
• the Synsorb is bound to the B subunit pentamer via the B subunit pentamer-receptor reaction. Conjugation with Synsorb adds further stability.
• Another embodiment of the invention involves the administration of nucleic acid vaccines. DNA encoding a His-Shiga toxoid is injected into a patient as naked
• DNA or the DNA is delivered to the body by a carrier system such as retro viruses, adenoviruses, or other carriers known in the art. Following administration, the patient mounts an immune response against transiently expressed foreign antigens.
• nucleic acid vaccines in general, are all nearing clinical trials. This approach to vaccines involves delivering the DNA encoding the desired antigen into the host by inserting the gene into a nonreplicating plasmid vector (Marwick, C.
• His-Shiga antibodies polyclonal and monoclonal, can also be used in the treatment, diagnosis, and prevention of infections related to Shiga toxins. Because of their increased specificity, monoclonal antibodies are preferred. His-Shiga toxin antibodies can be administered to humans or other mammals to achieve a protective immune response, for treatment or prophylaxis. Antibodies, in a physiologically acceptable carrier, may be administered orally or intraperitoneally. For this purpose, monoclonal antibodies are preferred and humanized monoclonal antibodies are particularly preferred. Positive clinical responses in humans have been obtained with monoclonal antibodies, and one skilled in the art would know how to employ Shiga monoclonal antibodies in humans.
• Another embodiment of the invention involves using antibodies to diagnose Shiga toxin infections.
• the antibody using well-known methods of immunoassaying, is brought into contact with a sample from a patient, such as a fecal sample.
• the antibody may be used to detect Shiga toxins in sample taken from cow, such as cow feces.
• meat may be tested using the anti His-Shiga toxin antibody for detection.
• a detection kit comprising the His-Shiga toxin antibody can be used for this purpose.
• a sandwich Elisa can be used.
• rabbit anti-His-Shiga toxin antibody can be used to capture toxin from a sample to be tested.
• Goat anti-His- Shiga toxin antibody can then be added followed by a secondary antibody such as mouse ⁇ -goat antibody conjugated to horseradish peroxidase.
• the antibody can be detected by standard methods.
• primary Ab 50 ⁇ l test sera diluted in blocking solution for example, start with 1 :50 and do eleven 1 :2 dilutions, or start with 1 :50 and do eleven 1 :10 dilutions), incubate 2 h/RT.
• secondary Ab goat horseradish-conjugated anti-mouse Ig, affinity purified (Boehringer Mannheim Corp., 91 15 Hague Rd., P.O. Box 50414, Indianapolis, IN. 46250,800-262-1640). Add secondary Ab diluted 1 :500 in blocking solution without azide. Incubate 1 h/RT.
• a titer is defined as an absorbance value >0.2 units above that obtained for mouse preimmune sera.
• Anti-Shiga toxin Abs obtained from animals may be used clinically if one changes the specificity of the antibody to human. Such techniques are well known to those of ordinary skill in the art. G. Winter et al., "Man-made antibodies," Nature, 349: 293-299 (1991); P.T. Jones et al., “Replacing the complementarity-determining regions in a human antibody with those from a mouse,” Nature, 321 : 522-525 (1986); P. Carter et al., “Humanization of an anti-pl85 f ⁇ £R2 antibody for human cancer therapy," Proc. Nad. AcadSci. USA, 89: 4285-4289 (1992). Such antibodies may be given to the sibling of an infected patient to reduce the risk of infection of the sibling. C. Raising Monoclonal Antibodies to His-Shiga Toxin
• Monoclonal antibodies directed against Shiga toxin are used to passively protect a patient against EHEC and Shigella dysenteriae type 1 infections. Monoclonal antibodies are generated from mouse cells, and the specificity of these antibodies are changed for use in humans. G. Winter et al., "Man-made antibodies," Nature, 349: 293-299 ( 1991 ); P.T. Jones et al., “Replacing the complementarity-determining regions in a human antibody with those from a mouse,” Nature, 321 : 522-525 (1986); P. Carter et al., “Humanization of an anti-pl ⁇ S” 1 2 antibody for human cancer therapy," Proc. Natl. AcadSci. USA, 89: 4285-4289 (1992). Monoclonal Abs represent a more "pure” antibody for administration to a patient.
• mice Five 4- to 5-week old female BALB/cJ mice are prebled, and immunized intraperitoneally with 25 ⁇ g His- Shiga toxoid suspended in 100 ⁇ l of TiterMax. Mice are boosted twice in two week intervals, intraperitoneally with 25 ⁇ g His-Shiga toxoid suspended in 100 ⁇ l of TiterMax. Seven days after each boost, blood (-300 - 500 ⁇ l) is collected from the tail vein. Sera are assayed for the presence of anti-Shiga toxin antibody by ELISA (as described above).
• mice producing high titers of anti-His Shiga toxin antibodies are boosted both intravenously and intraperitoneally with 25 ⁇ g of His-Shiga toxoid in 100 ⁇ l of PBS, sacrificed three days later, and sera collected.
• Spleen cells are isolated and fused to Sp2/0-Ag mouse myeloma cells (ATCC #CRL1581 ) at a ratio of 10 spleen cells to 1 myeloma cell. Fused cells are distributed into microdilution plates, and culture supernatants arc assayed by ELISA after 3-4 weeks of culture for anti-His-Shiga toxin antibodies.

Landscapes

• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Organic Chemistry (AREA)
• General Health & Medical Sciences (AREA)
• Medicinal Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Gastroenterology & Hepatology (AREA)
• Proteomics, Peptides & Aminoacids (AREA)
• Molecular Biology (AREA)
• Genetics & Genomics (AREA)
• Biophysics (AREA)
• Biochemistry (AREA)
• Pharmacology & Pharmacy (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
• Veterinary Medicine (AREA)
• Communicable Diseases (AREA)
• Animal Behavior & Ethology (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Oncology (AREA)
• Public Health (AREA)
• General Chemical & Material Sciences (AREA)
• Peptides Or Proteins (AREA)
• Medicines Containing Antibodies Or Antigens For Use As Internal Diagnostic Agents (AREA)
• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
• Micro-Organisms Or Cultivation Processes Thereof (AREA)
• Medicines That Contain Protein Lipid Enzymes And Other Medicines (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=21827219

Family Applications (1)

Country Status (6)

Families Citing this family (20)

Family Cites Families (2)

• 1997
  • 1997-09-09 EP EP97939845A patent/EP0929679A2/de not_active Withdrawn
  • 1997-09-09 CA CA002265887A patent/CA2265887A1/en not_active Abandoned
  • 1997-09-09 WO PCT/US1997/015836 patent/WO1998011229A2/en not_active Ceased
  • 1997-09-09 AU AU41845/97A patent/AU4184597A/en not_active Abandoned
  • 1997-09-09 AR ARP970104115A patent/AR010218A1/es unknown
  • 1997-09-09 JP JP10513748A patent/JP2001500730A/ja active Pending

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events