HIV TYPE-1 DIVERSITY AND THE RELIABILITY OF THE HETERODUPLEX MOBILITYASSAY

We investigated HIV-1 diversity by means of heteroduplex mobility assa y (HMA) genotyping. We studied 199 samples from patients originating f rom 26 countries and living in France. The HMA successfully genotyped 182 (91%) of these samples, as follows: 77 (42%) subtype A, 57 (31%) s ubtype B, 5 (3%) subtype C, 5 (3%) subtype D, 8 (4%) subtype E, 22 (12 %) subtype F, 5 (3%) subtype G, and 3 (2%) subtype H. We were not able to genotype 12 samples by means of the HMA. These latter strains were sequenced, and phylogenetic analyses revealed that they were highly d ivergent subtype A-, D-, or G-related strains. Eight (of 12) subtype D strains were indeterminate by HMA, owing to the broad intrasubtype di versity, suggesting that new reference subtype D plasmids are required , as previously proposed. Thirty-seven strains belonging to the differ ent subtypes were sequenced, and the results showed perfect concordanc e with the HMA results. Interlaboratory quality controls confirmed the reliability of the HMA for HIV-1 subtyping, despite the extensive vir al variability. However, plasmid selection must be continuously revise d to cover viral diversification.