Characterization of human immunodeficiency virus type 1 vif gene in long-term asymptomatic individuals.

We have determined the sequence of the human immunodeficiency virus type 1 (HIV-1) vif genes from a cohort of 42 long-term nonprogressors (LTNP) and compared these sequences to those of 8 late progressors. The coding potential of the vif open reading frame directly derived by nested PCR from uncultured peripheral blood mononuclear cell DNA was conserved in all 50 individuals. The nucleotide distances between vif sequences were not significantly different between LTNP and late progressors, indicating similar selections of viruses within both types of long-term HIV-1-infected subjects. However, a statistically significant correlation between an amino acid signature at position 132 of Vif and the viral load was found within LTNP. Namely, amino acid Ser was associated with low viral load and amino acid Arg with high viral load. This signature was also observed when LTNP with low viral load were compared to progressors. The Ser132 signature was introduced in place of Arg132 present in the HIV-1 YU-2 Vif prototype into chimeric viruses to assess the impact of Vif signature on the virus. While the replication properties in the SupT1 cell line were unmodified, the mutagenized virus revealed a fivefold decreased replication in activated PBMC, suggesting a possible role of this Vif signature for viral production in vivo.