应用噬菌体随机肽库技术筛选缓慢进展者HIV-1中和抗体模拟表位

Screening of HIV-1 neutralizing antibody mimotopes in slow progressor from phage display peptide library

目的以含有高水平HIV-1中和抗体的血浆为配体筛选HIV-1中和抗体模拟性抗原表位。方法为获取中和抗体识别的模拟表位，采用多轮感染外周血单个核细胞（PBMC）中和实验检测11例HIV感染缓慢进展者血浆中和抗体水平，利用噬菌体随机肽库对具有高水平中和抗体的血浆进行生物淘筛，ELISA方法鉴定阳性克隆。阳性克隆测序后与HIV Env gp41序列进行了同源性分析，应用Local Blast软件分析中和抗体模拟表位。结果3轮淘筛之后，得到22个阳性克隆。分析发现包括c8等12个可能的中和抗体模拟表位，位于gp41Ⅱ类功能区的C40对HIV-1血浆具有较高的抑制率。结论利用缓慢进展者血浆IgG抗体筛选噬菌体随机肽库，能够有效的获得多个HIV-1中和抗体相关抗原模拟表位。

Objective To screen mimetic HIV-1 neutralizing epitopes from plasma with high level neutralizing antibody, and to provide useful information for further study of the interaction between antigen and antibody. Methods In order to gain neutralizing antibody recognized mimotopes, we detected neutralizing antibodies levels of 11 HIV-1 infected slow progressors by PBMC-based neutralization assays. High-titer HIV-neutralizing antibodies from plasma of SPs was used as the ligand for biopanning by phage-displayed random peptide library. Positive phage clones was evaluated by ELISA, sequenced, and analyzed for homology to HIV-1 env by local BLAST to deduce the neutralizing peptide. Results Twenty-two clones were obtained consistent with requirement through three rounds biopanning. After comparison analysis, twelve clones include C8 were obtained as mimotopes of neutralizing antibody, C40 located in gp41 Ⅱ cluster with the highest titer by inhibition ratio may be as neutralizing epitope. Conclusion By the use of IgG antibodies from SPs to screen the phage random polypeptide library, one can acquire multiple phage mimetic peptides of HIV related antigen epitope.