从噬菌体库中筛选抗SARS病毒S蛋白的Fab中和活性抗体研究

目的 从SARS病毒噬菌体抗体库中筛选出具有中和活性的抗S蛋白Fab片段抗体。方法ELISA方法对抗体库进行富集筛选及人源抗体克隆结合活性的测定，竞争ELISA初步筛选有中和活性的抗体，中和试验进一步确定中和活性，进而对其序列进行测定和分析。结果特异性富集了抗S蛋白噬菌体抗体，竞争ELISA筛选出两株抗体可部分阻断中和抗体2C5与S蛋白的结合，中和试验确定其具有一定巾和活性，编号为M1A和P8A，测序结果表明它们为两株不同的抗体克隆。结论筛选获得了两株抗体可部分中和SARS病毒活性，它们的获得为探索SARS病毒感染的被动免疫治疗打下了一定基础。

Screening of human neutralizing Fab molecules to spike protein of SARS virus from phage library

Objective To select human neutralizing Fab molecules to spike protein from human phage antibody combinatorial library. Methods The library was biopanned and the binding of human antibody to spike protein was detected by ELISA, and the neutralizing Fab was pre screened by the inhibition ELISA; furthermore, neutralizing test was utilized to confirm the neutralizing capacity of the antibody selected by inhibition ELISA, followed by nucleotide sequencing of the two Fab molecules. Results Phage antibodies to spike protein were specifically enriched and two Fab fragments selected were capable of inhibiting binding activity of monoclonal antibody 2C5 to spike protein, M1A and P8A. Neutralizing test confirmed partial neutralizing capability. Alignment of sequence showed that the two Fabs fragments represented individual clones. Conclusion Two neutralizing antibodies against SARS virus were obtained, which may be helpful for the study of passive immunoprophylaxis against SARS virus.