中和性马抗体对SARS-CoV感染的防治作用

Protection of mammalian cells from severe acute respiratory syndrome coronavirus infection by equine neutralizing antibody

目的探讨马抗SARSCoV中和性抗体是否对SARSCoV感染有防治作用。方法用SARSCoV(BJ01株)免疫马匹,从免疫马血清中制备IgGs及其F(ab’)2片段。通过细胞病变法(CPE)、MTT法和空斑形成实验(PFU)等方法,在体外培养的VeroE6细胞中检测F(ab’)2片段对SARSCoV感染的预防性和治疗性作用。再在Balb/c小鼠体内模型中,用CPE法和定量RTPCR方法检测该抗体的保护性效应。结果CPE、MTT和PFU三种方法证实来自三匹马的血清F(ab’)2的中和滴度均达到1∶1600以上。体内实验证实,50μg的F(ab’)2片段可以完全中和1×104TCID50SARSCoV。结论马抗SARSCoV抗体在体内外均能有效地中和SARSCoV和预防其感染宿主细胞,为马抗体将来在大的灵长类动物或人体内进行实验提供实验依据。

Objective To investigate the effects of equine neutralizing antibody on SARS-CoV infection in primate cells. Methods IgGs and their pepsin-dlgested F（ab＇）2 fragments were prepared from the sera of three horses inoculated with purified SARS-CoV （BJ-01 strain）. The protective effects of the F（ab＇）2 fragments against SARS-CoV infection was determined in cultured Vere E6 cells by cytopathic effect （CPE）, MTT, and plaque-forming assays, as wellas in a Balb/c mouse model by CPE and quantitative RT-PCR assays. Results The neutra-lization titres of F（ab＇）2 from three horses all reached at least 1：1600 and 50/tg of the F（ab＇）2 fragments could completely neutralize 1×10^4 TCID50 SARS-CoV in vivo. We also observed that F（ab＇）2 against BJ-01 strain could protect cells from infection of the variant GZ-01 strain in vitro and in vivo as well. Conclusion The antibody against SARS-CoV raised in horses could neutralize SARS-CoV and prevent its infection in host efficaciously. Our work provided experimental support for testing the protective equine immunoglobulin in future large primate or human trial.