Abstract

PIP: Although both HIV-1 subtypes B and E have been identified from infected individuals in Thailand, subtype E is the main form of HIV currently circulating in the country. Full-length gp160 sequences were obtained from 2 early seroconverters from northern Thailand in a study to learn more about the HIV-1 sequences currently being transmitted among recently infected individuals. Subject A01021 was a female prostitute who tested negative for antibodies to HIV-1 in April 1993, then positive in July 1993. Subject E11429 was a male military conscript who tested negative for antibodies to HIV-1 in May 1993, then positive in November 1993. Uncultured peripheral blood mononuclear cells (PBMCs) were collected from these two individuals in January 1994 and about 2500-bp segments containing the full-length gp160 gene were amplified by nested polymerase chain reaction (PCR) using the Expand high-fidelity PCR system. The nucleotide sequences of full-length gp120 from the subjects were subtype E based upon phylogenetic analysis. The gp120 sequences from the 2 seroconverters appeared more diverse than previously published subtype E HIV-1 sequences from Thailand. Overall, however, the subtype E HIV-1 gp120 sequences from Thailand were less diversified compared to the subtype E HIV-1 isolated from people with AIDS in the Central African Republic. Most of the observed amino acid variations were limited to the 5 variable regions in gp120. Therefore, vaccine strategies which elicit immune responses to the conserved regions of HIV-1 env protein will have a greater possibility of success.