[Genetic variation of gag gene in HIV-1 subtype B infections from Henan and Shanxi provinces of China].
The 109 whole blood samples were collected from HIV-1 infected former blood donors in Henan and Shanxi. The RNA templates were extracted from plasma and used for the full gag gene amplification and sequencing. The sequences were divided into 3 groups according to sampling year. The Entropy software was used to identify the amino acids with composition difference among different groups of amino acid sequences. The results showed that there existed 8 and 13 amino acid sites with the statistical significance difference, respectively, in sequences in year 2004 and 2005, compared to those in 2002. Among them, there existed 5 amino acid sites in two groups. Of 16 amino acid sites, the increasing polymorphism and the decreasing polymorphism along the sampling year were observed in 10 and 6 amino acid sites respectively. Of 10 sites with increased polymorphism, 8 sites were located in the CTL epitopes recognized and presented by the main HLA alleles existed in Chinese population. The 6 sites with decreasing polymorphism all existed in main domains of Gag proteins.