title: Strong protection against ricin challenge induced by a novel modified ricin A-chain protein in mouse model.
abstract: Ricin toxin (RT) is an extremely potent toxin derived from the castor bean plant. As a possible bioterrorist weapon, it was categorized as a level B agent in international society. With the growing awareness and concerns of the "white powder incident" in recent years, it is indispensable to develop an effective countermeasure against RT intoxication. In this study we used site-directed mutagenesis and polymerase chain reaction (PCR) techniques to modify the gene of ricin A-chain (RTA). As a result, we have generated a mutated and truncated ricin A-chain (mtRTA) vaccine antigen by E.coli strain. The cytotoxicity assay was used to evaluate the safety of the as-prepared mtRTA antigen, and the results showed that there was no residual toxicity observed when compared to the recombinant RTA (rRTA) or native RT. Furthermore, BALB/c mice were subcutaneously (s.c.) vaccinated with mtRTA 3 times at an interval of 2 weeks, and then the survivals were evaluated after intraperitoneal (i.p.) or intratracheal challenge of RT. The vaccinated mice developed a strong protective immune response that was wholly protective against 40 × LD50 of RT i.p. injection or 20 × LD50 of RT intratracheal spraying. The mtRTA antigen has great potential to be a vaccine candidate for future application in humans.
authors.affiliation: a State Key Laboratory of Pathogen and Biosecurity; Beijing Institute of Microbiology and Epidemiology ; Beijing , China.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
authors.forename: Hao
authors.initials: H
authors.lastname: Yang
authors.forename: Lin
authors.initials: L
authors.lastname: Kang
authors.forename: Shan
authors.initials: S
authors.lastname: Gao
authors.forename: Wenwen
authors.initials: W
authors.lastname: Xin
authors.forename: Wenwu
authors.initials: W
authors.lastname: Yao
authors.forename: Xiangjin
authors.initials: X
authors.lastname: Zhuang
authors.forename: Bin
authors.initials: B
authors.lastname: Ji
authors.forename: Jinglin
authors.initials: J
authors.lastname: Wang
mesh_terms: D000280:Administration, Inhalation; D000818:Animals; D023482:Bioterrorism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D007116:Immunization, Passive; D007279:Injections, Subcutaneous; D007928:Lethal Dose 50; D051379:Mice; D008807:Mice, Inbred BALB C; D016297:Mutagenesis, Site-Directed; D009500:Neutralization Tests; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction; D012276:Ricin / Q000008:administration & dosage / Q000276:immunology* / Q000506:poisoning*; D016019:Survival Analysis; D014612:Vaccines / Q000008:administration & dosage / Q000235:genetics* / Q000276:immunology*
chemical_list: D014612:Vaccines; D012276:Ricin
keywords: ELISA, enzyme-linked immunosorbent assay; FBS, fetal bovine serum; HRP, horseradish peroxidase; IPTG, isopropyl-1-thio-β-galactopyranoside; LD50, median lethal dose; RT, ricin toxin; RTA, ricin toxin A chain; RTB, ricin toxin B chain; SD, standard deviation; i.p, intraperitoneally; i.p., intraperitoneal; immunity; intratracheal; mRTA, mutated RTA; mtRTA, mutated and truncated RTA; mutant; rRTA, recombinant RTA; ricin; s.c., subcutaneously subcutaneous; toxicity; toxin; truncation; vaccine