HIV-1 V2区175位变异可提高中和抗体对病毒的结合能力

Human immunodeficiency virus type 1 （HIV-1） V2 L175P mutation increases the binding capability of neutralizing antibodies to HIV-1

目的探讨HIV-1V2区175位变异对于v3中和抗体与病毒结合能力的影响。方法使用真核细胞表达质粒分别串联HIV-1野生型和突变型的env基因和绿色荧光蛋白GFP，并转染293T细胞，使gp120表达到293T细胞的表面，并根据GFP荧光来检出转染成功细胞。然后使用免疫染色和双荧光流式细胞仪检测几种常见V3区中和抗体对野生型和突变型gp120的结合力。结果L175P突变使表达在293T细胞表面的gp120三聚体与3种V3区特异性抗体结合的荧光强度差异有统计学意义，与阴性对照的荧光强度分布差异有统计学意义，图形的位置和峰值均有变化，平均荧光强度MFI显著升高；而表达野生株gp120三聚体的293T细胞与V3抗体作用后，曲线与阴性对照的荧光强度分布基本重叠，MFI基本相同。结论提示V2区突变可以提升病毒对V3抗体中和作用的敏感性。

Objective To study the impact of HIV-1 V2 L175P mutation on the binding capability of anti-V3 neutralizing antibodies to HIV-1. Methods A series of eukaryotic cell expression plasmids were used to concatenate wild type and mutant env gene of HIV-1 and green fluorescent protein （GFP） gene. The recombinant plasmids were transfected into 293T cells to express HIV-1 gp120 protein on the surface of cells. The successfully transfected cells were screened by GFP florescence marker. Immunostaining and dual fluorescence flow cytometry were performed to test the binding affinity of several common V3 region specific neutralizing antibodies to wild type or mutant gpl20 proteins. Results The mean fluorescence intensity （MFI） of mutant gp120-expressing 293T cells were significantly higher than that of negative control cells （expressing GFP）. Flow cytometry showed that the curve for mutant gp120-expressing 293T cells was obviously different in shape and peak from that for the negative control, while most parts of the curve for the wild type gp120-expressing 293T cells overlapped with those for the negative control. Conclusion The V2 region mutation may increase the sensitivity of HIV-1 to the neutralization by V3 region specific antibodies.