HIV-1 diversity in Brazil: Genetic, biologic, and immunologic characterization of HIV-1 strains in three potential HIV vaccine evaluation sites

The Brazilian Network for HIV Isolation and Characterization was establishe d for the surveillance of HIV variability in Brazil. Here, we report charac terization of HIV strains and virus-specific immune responses from 35 clini cal samples collected from three potential HIV vaccine sites. Three genetic subtypes of HIV-1 were identified by heteroduplex mobility assay (HMA) B ( in 82.9% of the samples), F (14.3%), and C (2.9%). Phylogenetic analysis ba sed on the C2V3/env DNA sequence from all 25 specimens examined was 100% co ncordant with HMA results. Four Variants of subtype B with different tetrap eptides at the tip of the V3 loop were found: the GPGR motif (North America n), GWGR motif (Brazilian B"), and two minor variants, GFGR and GPGS, as pr eviously detected. No significant association was found between HIV-1 subty pes and the mode of transmission or biologic properties of HIV-1 isolates ( derived from 88.6% of the specimens). Only 5 of 16 isolates studied were ne utralized by the autologous sera. Consistent with previous results, no rela tion between viral subtype and peptide enzyme-linked immunosorbent assay (E LISA) seroreactivity or neutralization was evident. This study also demonst rated the effectiveness of the collaborative approach followed by Brazilian scientists when addressing a complex subject such as HIV variability.