Identification of human immunodeficiency virus type 1 subtypes B and F, B/F recombinant and dual infection with these subtypes in Argentina

DNA sequences encoding the third variable region (V3) of human immunodefici ency virus type-1 (HIV-1) envelope glycoprotein gp120 were obtained from 18 infected individuals residing in different regions of Argentina. Proviral DNA representing the env V3 region was obtained by PCR from uncultured peri pheral blood mononuclear cells (PBMC) and genetic heterogeneity was examine d by phylogenetic analysis. Sequences representing the gag p17 region were also obtained for a subset of these samples. Moreover, 1 sample that it was not possible to classify according to initial phylogenetic analysis was fu rther analysed by molecular cloning of both V3 and p17 regions. Phylogeneti c analysis according to different methodologies were performed comparing ob tained sequences with a set of reference sequences representing previously characterized HIV-1 subtypes. The recombinant identification program (RIP) was used to study the presence of possible recombinant sequences. Phylogene tic analysis demonstrated that viruses representing both subtypes B and F a re circulating among HIV-1 infected individuals in Argentina. In addition, RIP analysis showed that an initially unclassified sequence exhibited simil arities to subtypes B and F in different fragments of the V3 region. Separa te phylogenetic analysis of each of these fragments revealed divergent clus tering, suggesting that this sequence harbours a point of recombination wit hin the V3 loop. Interestingly, we also identified a dually infected indivi dual with viruses belonging to subtypes B and F, as demonstrated by molecul ar cloning analysis of the env V3 and the gag p17 regions. Taken together, our study shows that both subtypes B and F are circulating in different reg ions of Argentina. Moreover, the data presented here show that dual infecti ons with subtypes B and F can occur, and consequently B/F recombinant seque nces are arising in the region.