V3 sequences and paired HIV isolates from 52 non-subtype B HIV type 1-infected patients.

Viral isolation and V3 sequencing were performed for 52 patients with non-subtype B viruses. The HIV-1 isolation rate was 93%, and 98% of isolates were characterized as NSI. V3 sequences corresponding to NSI isolates were compared to non-subtype B sequences with corresponding SI isolates from the Los Alamos database. The two sequence groups significantly differed in number of sequences with 35 amino acids, net charge, Brigg's coefficient, loss of NGS at positions 6-8, and 11/25 genotype (p < 0.0001). Substantial discrepancies in V3 variability were also observed. Basic amino acids at positions 8, 21, 23, and 24 were more frequent in SI sequences as were uncharged amino acids at positions 5, 6, 7, 8, 12, 13, 25, and 34. When characterizing paired viral isolates and V3 sequences from patients with non-subtype B HIV-1, current V3 sequence-based criteria from subtype B appeared to discriminate well between NSI and SI sequences from non-subtype B patients.