Genetic characteristics of HIV-1 CRF01_AE strains circulating in Beijing / 中华流行病学杂志

ABSTRACT

Objective To analyze the genetic characteristics of HIV-1 CRF01_AE strains prevailing in Beijing. Methods Plasma samples were collected from the newly diagnosed HIV-1 individuals being reported during 2006 to 2008 in Beijing. Gag gene fragments were amplified from RNA template which were extracted from plasma by RT and nested PCR methods. 105 CRF01_AE sequences were analyzed by phylogcnetic methods and characterized through calculating the genetic distance and Entropy analysis. Results There were four main sub-clusters in the phylogenetic tree.We named them as sub-clusters Homo-Max ( 67 sequences ), Hetero( 6 sequences), Mix (8 sequences)and Homo-Min ( 18 sequences)respectively, based on the mode of transmission. It was found that no international reference strain was closely related to the sub-cluster Homo-Max, Hetero or Homo-Min,including 91 samples. The strains in sub-cluster Mix consisting 8 cases that were closely related to the strains identified in Thailand and Vietnam. Genetic distance analysis on gag genes showed that the diversity of sub-clusters Homo-Max and Homo-Min was obviously less than that of the sub-cluster Hetero or Mix. When compared with sub-cluster Mix, there were 37,29 and 11 significantly different nucleotides polymorphism compositions sites in sub-clusers Homo-Max Homo-Min and Hetero.Conclusion This was the first report describing that four main epidemic sub-clusters were existed in CRF01_AE strains prevailing in Beijing. The virus with sub-cluster Homo-Max was the dominant strain in this region with shorter period of circulation and higher proportion seen in the HIV-infected persons. The virus in sub-cluster Mix was highly homologic with the CRF01_AE strains from Thailand and Vietnam.