人类免疫缺陷病毒-1包膜糖蛋白进化对抗原表位及病毒亲嗜性的影响

The influences of the evolution of HIV-1 envelope gene on the epitopes and the tropism of the virus

目的调查同一供体来源的人类免疫缺陷病毒（HIV）-1感染不同个体后病毒包膜糖蛋白的变异、病毒侵入靶细胞能力以及包膜抗原主要中和表位的变化，为了解病毒感染规律及机体抗病毒免疫奠定基础。方法对病毒包膜糖蛋白基因序列进行基因离散分析；用包膜蛋白表达质粒与HIV-1骨架质粒共转染293T细胞构建包膜包膜假病毒，用假病毒感染HIV-1靶细胞U87．CD4．CCR5或U87．CD4．CXCR4细胞检测假病毒侵入靶细胞的能力及病毒亲嗜性；对包膜糖蛋白中已知的广谱中和抗体识别表位进行分析。结果24个有完整开放读码框的env基因克隆与河南省HIV-1毒株CNHN24的基因离散率为（7．91±0．78）％，与云南省分离毒株RIA2的基因离散率为（6．904-0．79）％。各可变区基因离散率呈现严重不均衡性，其中，VI／V2区的离散率最高，V4区的离散率次之，V3区离散率最小。包膜假病毒中既有CCR5亲嗜性和CXCR4亲嗜性的，也有双亲嗜性的包膜。而且上述包膜中主要中和表位IgGlbl2、2F5和4E10抗体识别表位保守，但447—52D抗体识别表位变异较大。结论同一来源的HIV包膜糖蛋自在4～7年间的不同受者体内发生了较大变异并影响了病毒侵入靶细胞的能力；主要广谱中和抗体的识别表位部分保守。

Objective To investigate the evolution of HIV-1 envelope （env） gene from the individuals in- fected by the virus from one donor, the entry mediated by the envelope glycoprotein and the variation in the main neu- tralizing epitopes of envelope. Methods The genetic distances of the HIV-1 envelope genes derived from previous studies were analyzed. A series of envelope-pseudotyped viruses were constructed by co-transfecting HEK293T cells with a HIV-1 plasmid bearing the firefly luciferase reporter gene and an envelope expression plasmid. The entry abili- ty of the envelope-pseudotyped viruses into U87. CIM. CCR5 or U87. CD4. CXCR4 cell lines was examined. The ami- no acid sequences.representing the epitopes to the broad-neutralizing antibodies within the envelope glycoproteins were also investigated. Results It was found that the genetic distance of the 24 env genes with complete open reading frame was （71 91 ±0.78） % towards HIV-I CNHN24, and （6.90 ±0.79） % towards RIAt2. Among the variable regions, the genetic distance of V1/V2 showed the biggest distance, and that of V3 showed the smallest distance. There were CCRS-tropie, CXCR4-tropic and CCR5/CXCR4-dual-tropic Env-pseudoviruses. Furthermore, in these envelopes, the epitopes to IgGl b12 2F5 and 4El 0 antibody were conserved, while the epitope to 447-52D was varia- ble. Conclusion There is definite env gene variation among the viruses derived from the same donor. The variation influences the entry ability and tropism of emelope pseudoviruses. The epitopes to the main broad-neutralizing anti- bodies are conserved.