抗弓形虫靶向抗菌肽的构建及其效应的初步评价  

Construction and protective effect of targeting antimicrobial peptide against Toxoplasma

作　　者：司进[1,2] 朱荫昌[1] 曹利民[3] 王晓婷[1] 梁幼生[1] 管晓虹[2] 

机构地区：[1]江苏省寄生虫病防治研究所,江苏省寄生虫分子生物学重点实验室,江苏省寄生虫病学重点学科,无锡214064 [2]南京医科大学分子生物学研究所 [3]华中科技大学同济医学院免疫学系

出　　处：《中国血吸虫病防治杂志》2005年第5期356-361,共6页Chinese Journal of Schistosomiasis Control

基　　金：江苏省寄生虫病学重点学科;江苏省寄生虫分子生物学重点实验室开放课题资助项目(WK005-008)

摘　　要：目的构建弓形虫主要表面抗原1单链抗体S1与爪蟾抗菌肽(magainin)的融合基因,在大肠杆菌中诱导表达,观察纯化的靶向抗菌蛋白抗弓形虫感染的效果。方法根据弓形虫主要表面抗原1单链抗体S1的编码序列设计引物从噬菌粒S1/pIT-2中扩增到S1基因;以其为模板,加入接头抗菌肽序列,采用重叠PCR法扩增得到S1基因与爪蟾抗菌肽的融合基因(S1M),将其克隆到原核表达载体pET-32c中,构建成S1与爪蟾抗菌肽基因的重组表达质粒S1M/pET-32c;测序验证后转化E.coliBL21,以IPTG诱导表达,用Ni2+螯合柱亲和纯化融合蛋白S1M,SDS-PAGE检测融合基因的表达和纯化的融合蛋白S1M;分别采用体内和体外试验观察纯化的靶向抗菌蛋白抗弓形虫感染效果。结果测序结果表明,成功地将弓形虫主要表面抗原1单链抗体S1与爪蟾抗菌肽的融合基因构建到原核表达载体pET-32c中;SDS-PAGE显示IPTG诱导表达的融合蛋白S1M大小约为43kDa,与预期的大小相一致,以包涵体的形式存在;通过变性条件下Ni2+亲和柱纯化获得S1M重组融合蛋白;体内和体外试验证实,经靶向抗菌蛋白处理过的弓形虫对小鼠的致病能力下降,应用靶向抗菌蛋白的弓形虫感染小鼠的存活时间与对照组相比有明显的提高。结论以抗弓形虫速殖子人源单链抗体作为靶向分子,以爪蟾抗菌肽作为效应分子,构建成功的靶向抗菌蛋白通过体内、外试验证实,具有一定的抗弓形虫感染的作用,虽然还不能完全杀灭弓形虫,但是在弓形虫生物治疗药物的研制方面进行了有益的探索,为弓形虫病的生物治疗提供了新的思路。Objective To construct, express and purify human scFv antibody （S1） against the recombinant SAG1 of Toxoplasma fused to magainin, and observe its protective effect against Totoplasma in infected mice. Methods The S1 scFv antibody gene amplified from phagmid S1/pIT-2 fused to magainin was cloned into procaryotic expression vector pET-32c. The recombinant plasmid S1M/pET-32c proved by DNA sequencing was transformed into E. coli BL21. and induced for fu sion expression of S1M with IPTG. The expressed SIM was purified with Ni^2＋ chelating HiTrap HP column and detected with SDS-PAGE. The effect of reduction of infection of Toxoplasma was observed through in vivo and in vitro experiments in mice. Results The fused gene of S1 and magainin was successfully cloned into procaryotic expression vector pET 32c proved by DNA sequencing. The recombinant S1M protein about ,3 kDa was expressed in E. coli as inclusion body, and prepared with Ni^2＋ column purification. Tachyzoite of Toxoplasma preincubated with S1M showed decreased infectivity in mice. the result of in vivo experiments showed that mice treated with S1M had longer survival time than the mice untreated. Conclusion The purified targeting antimicrobial peptide S1M could reduce the infectivity of tachyzoites of Toxoplasma in a certain extent and has a potential value for biological therapy of toxoplasmosis; otherwise, the constructed targeting antimic robial peptide S1M also provides a new model for biological therapy of toxoplasmosis.

关 键 词：弓形虫 单链抗体 抗菌肽 靶向 

分 类 号：R382.5[医药卫生—医学寄生虫学]