DIVERSITY OF ANTIBODY-BINDING TO V3 PEPTIDES REPRESENTING CONSENSUS SEQUENCES OF HIV TYPE-1 GENOTYPE-A TO GENOTYPE-E - AN APPROACH FOR HIV TYPE-1 SEROLOGICAL SUBTYPING

We investigated whether V3-binding assays might be useful to analyze h uman immunodeficiency virus type 1 (HIV-1) variants in different geogr aphic regions, We showed that strong cross-reactivity between subtype- specific V3 peptides is almost inevitable in standard indirect enzyme- linked immunosorbent assays (EIA), impairing precise serological subty ping, We therefore developed a subtype-specific EIA (HIV-1 SSEIA) that uses the principle of blocking by an excess of peptide in the Liquid phase, Using 231 serum samples collected from HIV-1-infected individua ls in 10 different geographical areas from 4 continents, we showed tha t this approach detected the dominant subtype reactivity in more than 97% of the cases, Internal controls (0 and 100% blocking) were used fo r every sample such that comparative analysis was possible, independen t of both the individual humoral response and the time of collection d uring the course of infection, This was validated by the excellent con cordance of the serological profiles of couples and the temporal stabi lity of the serological profile in individuals, The geographical distr ibution of the various subtypes in the SSEIA was in agreement with the present knowledge of the distribution of the various genotypes, Altho ugh the goal of this study was not an extensive seroepidemiological su rvey, our results showed that the various profiles in most of the regi ons were relatively homogeneous, but in central Africa there was a lar ge diversity of serological profiles, Cluster analysis identified a li mited number of V3 serogroups of serotypes within the HIV-1 group M. F ive serogroups, some of them divided into subgroups, were identified a nd characterized by a mean serological profile, Our data confirmed tha t subtypes A and C, although being dissimilar genetic subtypes, presen t conserved antigenic properties in the V3 region, and that the D subt ype is probably the most divergent within the group M (B Korber ed at, J Virol 1994;68:6730), Cluster analysis showed a clear correlation be tween position within the dendrogram and geographical origin of the sa mples, This is further support for the reliability and therefore the u sefulness of the SSEIA, This simple methodology may help facilitate th e analysis of the distribution of various HIV-1 subtypes circulating i n different populations and regions.