Subtype and Sequence Analysis of gag Genes among HIV-1 Strains Circulating in Beijing during 2007

To investigate the subtype distribution and sequence characteristics of HIV-1 strains prevalent in Beijing during 2007 and to analyze the relationship between distribution of HIV-1 subtypes and transmission routes,we collected the anti-conglutinated whole blood samples from HIV-1 newly infected individuals in Beijing during 2007 and separated plasma specimens from the aamples.RNAs were extracted and the gag genes from the various samples were amplified by RT-PCR and nest-PCR.The PCR products were sequenced directly and phylogenetic analyses of gag genes were performed using the MEGA2 software.Among 200 HIV-1 plasma samples,161 gag HIV-1 gene fragments were amplified and analyzed.Seven HIV-1 subtypes or circulating recombinant forms(CRFs) of HIV-1 including A1(1 strains),B(35 strains),Thai B(19 strains),C(3 strains),CRF01_AE(49 strains),CRF07_BC(51 strains),CRF08_BC(3 strain) were identified circulating in Beijing.The gene divergences inside the subtypes were different,with 7.7%,6.5%,6.7%,6.7%,5.5%,4.3%,5.8%,in subtype A1,B,Thai B,C,CRF01_AE,CRF07_BC,CRF08_BC,respectively.Subtypes CRF07_BC and CRF01_AE were predominant in Beijing account for 31.7% and 30.4% among samples.Seven HIV-1 subtypes exist in Beijing and the surveillance of HIV-1 gene variation should be paid more attention.