广州市男男性行为者HIV-1分子流行病学研究

目的了解广州市男男性行为人群（MSM）中，人类免疫缺陷病毒Ⅰ型（HIV-1）亚型流行状况和基因变异特征。方法从2006～2007年广州市发现的、全部19份经男男性传播感染的HIV-1阳性血清样本，应用套式聚合酶链式反应（Nested—PCR）分别扩增gag和fitly区基因，并测定、分析序列。结果被成功扩增的有17份样本，获得13份env基因序列和17份gag基因序列。经系统进化树分析，11份（64．71％）为CRF01_AE，2份（11．76％）为CRF07_BC，4份（23．53％）为B。各亚型组内基因离散率：在env区，CRF01_AE为（8．27±0．93），CRF07_BC为（11．04±1．72），B为（16．65±1．78）；在gag区，CRF01_AE为（5．36±0．68），CRF07_BC为（4．29±1．14），B为（11．75±1.35）。V3环顶端四肽分析显示：8份CRF01_AE和2份CRF07_BC V3环顶端四肽均为GPGQ；3份B亚型中2份为GPGR，1份为GWGR。根据V3环关键氨基酸推测辅助受体使用情况，结果显示：所有样本均被预测使用CCR5辅助受体。结论广州市MSM人群HIV-1感染者中，至少存在CRF01_AE、CRF07_BC 2种重组亚型和B亚型的流行，且大部分流行株可能为使用CCR5辅助受体的巨嗜细胞嗜性／NSI毒株。

Molecular epidemiology of HIV-1 infection among MSM in Guangzhou

Objective To investigate the subtype and sequence characteristics of HIV 1 prevalent strains among MSM in Guangzhou. Mehods HIV-1 RNA was extracted from sera of 19 HIV-1 infected MSM. The HIV-1 gag and env gene region was amplified by nested-PCR and was sequenced and analyzed. Results Seventeen samples were successfully amplified and phylogenic analysis showed that of these 17 samples 11 （64.7%） were CRF01_AE,2 （11.76%） were CRF07_BC and 4 （23.53%） were subtype B. The distance within subtype showed that CRF01_AE was 8.27±0.93,CRF07_BC was 11.04±1.71 and subtype 13 was 16.65±1.78 in env region;CRF01_AE was 5.36 ±0.68,CRF07 BC was 4.29±1.14 and subtype B was 11.75±1.35 in gag region. The analysis of V3 loop amino acid sequence revealed that all CRF01 AE and CRF07_BC strains had the same type of V3 loop central motif; GPGQ. V3 loop central motif of 2 strains among 3 subtype B was GPGR and the other showed GWGR. Predictions for the potential use of coreceptors on the basis of the critical amino acids within V3 loop showed that all strains utilized CCR5. Conclusion CRF01 AE,CRF07_BC and subtype B are circulating among MSM in Guangzhou and the majority of circulating strains are likely to be non-syncytium-inducing （NSI） viruses which use CCR5.