PHYLOGENETIC EVALUATION OF KENYAN HIV TYPE-1 ISOLATES

Diversity among global isolates of HIV-1 presents a formidable challen ge for vaccine development, As distinct clades of the virus are recogn ized, it will be important to monitor their geographic distribution an d divergence, In this study, we characterized HIV-1 subtypes from 17 s eropositive individuals in Nairobi and Mombasa, Kenya, Seventy-one per cent of viruses were clade A and 29% were clade D. The most divergent clade A isolate in our survey, Q45-CxA, grouped closely with two other taxa that were previously reported as having no distinct clade affili ation, Thus, these data may suggest the emergence of an outlier group of clade A variants or a new subtype of HIV-I, Phylogenetic relatednes s of the 17 Kenyan isolates was determined separately for C2-V3 and V2 sequences off envelope and subtype designation for these isolates was independent of the region analyzed. However, evaluation of transition s, transversions, and specific character state changes indicated that mutations characterizing V2 differed from those in V3 for clade A and clade D isolates, Comparison of secondary structural characteristics o f the V1-V3 region between a clade A and a clade D virus revealed cons ervation of moths.