不同亚型的人类免疫缺陷病毒Ⅰ型毒株混合感染分析

目的：了解我国人类免疫缺陷病毒（HIV）感染中是否存在不同HIV－1亚型混合感染，分析其传染来源，方法：应用巢式－PCR方法对3例HIV－1感染外周血单个核细胞的HIV－1膜蛋白基因进行扩增。并对C2－V3及其邻区360个核苷酸序列进行测定和分析，计算基因离散率和系统进行化树。结果：3例感染体内有B和C或B′和E2种不同HIV－1亚型毒株序列，各亚型毒株与相应的Bcon、Ccon、Econ国际亚型毒株序列间的基因离散率分别为5．07％－7．26％、3．23％、5．38％－5．99％；同一个体内不同亚型毒株序列间的基因离散率分别为23．52％、20．69％、28．44％；根据gp120V3环顶端四肽序列特征，发现有卖淫和静脉吸毒史妓女体内的sz46-1具有典型的欧美B亚型GPGR序列，sz8-2为GPGH，其他毒株均为泰国B（B′）和E亚型所特有的CPGQ序列；进一步系统树分析显示，sz12、sz46-1与Bcon丛集一起,sz1-1和sz8-2,sz46-2分别与Econ、Ccon丛集。结论同一个体可以同时感染不同亚型HIV－1毒株，多种高危行为可能是导致混合感染的主要原因。

Analysis of HIV-1 seropositive individual infected with different subtypes

OBJECTIVE: To investigate whether there existed any individuals infected with different subtypes of human immunodeficiency virus type 1 (HIV-1) and to analyze their source of infection. METHODS: Membrane protein gene (env) of HIV-1 in uncultured single peripheral blood monocytes (PBMCs) from HIV-1 seropositive individuals found in Shenzhen was amplified by nested polymerase chain reaction (PCR). The C2-V3 region and its adjacent region (360 bp) of them were sequenced and analyzed, and their divergence rate and systematic phylogenetic tree (cladogram) were calculated. RESULTS: There existed sequences of B and C or B and E strains of HIV-1 subtype in three infected individuals in Shenzhen. Gene divergence rates between different subtypes and corresponding international subtype reference strains Bcon, Ccon and Econ were 5.07%-7.26%, 3.23% and 5.38%-5.99%, respectively, and those between different subtypes strains in the same individual were 23.52%, 20.69% and 28.44%, respectively. GPGR sequence of typical Europe and America subtype B was found in strain sz46-1 from prostitute with intravenous drug abuse, based on their tetra-peptide sequence characteristics in the crown of gp 120 V3 loop, strain sz8-2 was GPGH and other strains were GPGQ sequence characterized by Thai B (B') and E subtypes. Furthermore, phylogenetic tree analysis showed that strains sz1-2, sz8-1 and sz46-1 were clustered with international reference sequence Bcon, strain sz1-1 clustered with Econ, and strains sz1-1 and sz8-2 clustered with Ccon. CONCLUSION: These findings suggested that an individual could be simultaneously infected with different HIV-1 subtypes, which could probably be caused by his or her own multiple high-risk behavior.