title: A recombinant mutant abrin A chain expressed in Escherichia coli can be used as an effective vaccine candidate.
abstract: We used site-directed mutagenesis to mutate two key amino acid residues, Glu164 and Arg167, of abrin A chain (ABRA), creating a mutant ABRA(E164AR167L). The mutant ABRA(mABRA) encoded by mABRA(E164AR167L) was expressed in the cytoplasm of Escherichia coli, and used to develop an effective vaccine to protect mice against native abrin intoxication. The cytotoxicity of mABRA was dramatically reduced as compared to that of recombinant ABRA(rABRA) and native abrin, but the antigenicity and immunogenicity remained the same. Balb/c mice were vaccinated with purified mABRA, and survival was evaluated after challenge with native abrin. Mice that were given three vaccinations developed a protective immune response that was 100% protective against an intraperitoneal (i.p.) administration of 10×LD50 of native abrin. Furthermore, the sera from immunized mice provided complete passive protection for naive mice. This study describes the generation of a substantial amount of mABRA from E. coli and the potential application of mABRA as an effective vaccine candidate for humans, to protect against a high-dose of native abrin.
authors.affiliation: State key Laboratory of Pathogen and Biosecurity, The Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China.
authors.forename: Yan-Hui
authors.initials: YH
authors.lastname: Han
authors.forename: Shan
authors.initials: S
authors.lastname: Gao
authors.forename: Wen-Wen
authors.initials: WW
authors.lastname: Xin
authors.forename: Lin
authors.initials: L
authors.lastname: Kang
authors.forename: Jing-Lin
authors.initials: JL
authors.lastname: Wang
mesh_terms: D000036:Abrin / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology; D029912:Abrus / Q000009:adverse effects; D000818:Animals; D000906:Antibodies / Q000097:blood; D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology; D017422:Sequence Analysis, DNA; D014611:Vaccination; D014614:Vaccines, Synthetic / Q000276:immunology*
chemical_list: D000906:Antibodies; D011994:Recombinant Proteins; D014614:Vaccines, Synthetic; D000036:Abrin