Sequence analysis of V3 loop region of HIV-1 strains prevalent in India.

The third variable (V3) domain of human immunodeficiency virus type 1 (HIV-1) env gene has been found to elicit type-specific neutralizing antibodies as well as a cytotoxic and helper T-cell response in both humans and animals. We analyzed the V3 domain of 8 HIV-1 isolates from India by using polymerase chain reactions. The V3 loops of 7 Indian isolates contained the apical tetra peptide GPGQ, while the V3 loop of one Indian isolate carried the apical tetra peptide GPGK. The amino acid sequences of the seven Indian isolates were closely related to each other, with an average of the nucleotide sequence homology of 96.0% (94.6 to 97.6%). The marked relatedness of the amino acid sequences among the seven Indian HIV-1 isolates indicated a recent and very rapid spread of this HIV-1 variant in Bombay. The amino acid sequence of the C2/V3 region of env gene of the 7 Indian isolates were homologous to the C subtype reported by Meyers et al. These findings could be useful in assessing the sources of infection and developing an AIDS vaccine.