V3 REGION POLYMORPHISMS IN HIV-1 FROM BRAZIL - PREVALENCE OF SUBTYPE-B STRAINS DIVERGENT FROM NORTH-AMERICAN EUROPEAN PROTOTYPE AND DETECTION OF SUBTYPE-F

Viral DNA sequences were determined over the V3 region of env from 28 infected individuals living in the high HIV-1 prevalence Brazilian cit ies of Rio de Janeiro and Sao Paulo. Twenty-six belonged to envelope s equence subtype B, prevalent in North America and Europe, and one was classified as subtype F, found recently in Brazil and in Romania (one appeared to be a B/F recombinant). Octameric sequences at the tip of t he subtype B V3 loops were variable and distinct from those prevalent in North America and Europe. The GPGR motif, prevalent in North Americ an/European strains, was found in only 8 (28.5%) sequences, whereas GW GR was found in 12 (43%) and novel sequences in 8 (28.5%). Brazilian s ubtype B sequences also diverged from the consensus North American/Eur opean strains over the remainder of the V3 loop. These results suggest that Brazilian HIV-1 B strains may have important antigenic differenc es from prototype subtype B strains currently being evaluated for use in HIV vaccines. These results should be taken into account for future vaccine programs in Brazil.