Predominance of CCR5-dependent HIV-1 subtype E isolates in Cambodia

To investigate the genetic and biologic features of HIV-I strains circulati ng in Cambodia, viruses from 95 HIV-l-seropositive individuals were subtype d by heteroduplex mobility assay (HMA) and 23 were further analyzed for the ir biologic characteristics. Eighty-nine individuals were clearly infected by HIV-1 subtype E. The other six samples were sequenced, together with 17 HMA subtype E samples. All but one of the 23 Cambodian env sequences cluste red with previously described Thai and Vietnamese subtype E sequences, bear ing a GPGQ motif at the tip of the V3 loop; the last had a GPGR motif and w as phylogenetically equidistant from Asian and African subtype E viruses. N onsyncytium-inducing, CCR5-dependent viruses predominated in patients of cl inical stage B even in some with a high viral load and were detected in abo ut 50% of the patients of stage C. All syncytium-inducing strains, mostly f rom AIDS patients, used both CCR5 and CXCR4. The presence of syncytium-indu cing viruses did not correlate with the plasma viral load. These data show that CCR5-dependent HIV-I subtype E is currently predominant in Cambodia. T he analysis of clinical and virologic markers strongly supports the idea th at dynamics of the viral population during subtype E infection in Southeast Asia is similar to that of subtype B infection in Europe and the United St ates.