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经套式聚合酶链反应（ｎｅｓｔｅｄ－ＰＣＲ）对１７份１９９５年初采集于云南瑞丽市人免疫缺陷病毒１型（ＨＩＶ－１）阳性静脉吸毒者外周血单核细胞（ＰＢＭＣｓ）的核酸样品进行扩增，从１７份样品中获得了ＨＩＶ－１膜蛋白（ｅｎｖ）基因的核酸片段，并对其Ｃ２－Ｖ３及邻区４５０个核苷酸序列进行了测定和分析。结果表明，１７份样品中存在Ｂ和Ｃ两种亚型的ＨＩＶ－１毒株序列，其亚型内的基因离散率分别为５８％和２２％，与Ａ－Ｅ参考亚型及部分Ｂ和Ｃ亚型代表株序列相比较，属Ｂ亚型的１２个毒株与包括泰国、缅甸及云南瑞丽代表株ｙｎ２８９在内的Ｂ亚型毒株序列十分接近，基因离散率在４４％～４９％的范围内；属Ｃ亚型的５个毒株则与主要代表印度Ｃ亚型毒株的共享序列ｃｃｏｎ及瑞丽Ｃ亚型代表毒株ｙｎ２７２十分相似，其基因离散率均为１９％。以上数据进一步确认我们的结论，即ＨＩＶ－１在瑞丽的流行以Ｂ亚型毒株为主、Ｃ亚型的传人和流行时间较短。对Ｂ亚型毒株Ｖ３环序列的分析还发现，位于Ｖ３环顶端的四肽序中ＧＰＧＱ占５０％，ＧＰＧＲ则仅占２５％，且编码其精氨酸（Ｒ）的密码子均为ＣＧＡ而不是ＡＧＡ。此结果与我们根据早期瑞丽ＨＩＶ－１毒株序列研究结果得出的推测?
17 nucleic acid samples of peripheral blood mononuclear cells (PBMCs) from HIV-1 positive intravenous drug users collected in early 1995 in Ruili, Yunnan were amplified by nested-PCR (nested-PCR) The nucleic acid fragment of HIV-1 envelope protein (env) gene was obtained from 17 samples and 450 nucleotides of C2-V3 and its adjacent regions were determined and analyzed. The results showed that there were 17 strains of HIV-1 strains with B and C subtypes. The genetic divergence rates in subtypes were 58% and 22%, respectively, which were similar to those of A-E reference subtype 12 strains belonging to subtype B were very close to those of subtype B subtype B strains including Thailand, Myanmar and Yunnan Ruili. The gene divergence rate was 4 4% ~ 49%. Five strains belonging to C subtype were closely related to the shared sequence ccon representing the C subtype of Indian strain and the yn272 representative strain of subtype C of Ruili. The gene divergence Rates were 1 9%. The above data further confirm our conclusion that the prevalence of HIV-1 in Ruili is mainly of subtype B, and the transmission and release of subtype C are short. Analysis of the V3 loop of the subtype B strain also revealed that GPGQ accounted for 50% of the tetrapeptide located at the top of the V3 loop and only 25% of GPGR, and all of the codons encoding arginine (R) were CGA Not AGA. This result is in line with our conjecture based on the results of the earlier Ruili HIV-1 strain sequence study.