HIGH ANTIGENIC CROSS-REACTIVITY OF THE V3 CONSENSUS SEQUENCES OF HIV-1 GP120

The principal neutralization determinant (PND) of the human immunodefi ciency virus type 1 (HIV-1) is located within the variable V3 region o f the external envelope protein gp120. Although it is recognized that V3 sequences induce antibody response with restricted neutralization a ctivity in vitro, we observed that the V3 consensus sequences represen ting North American/European and African isolates were highly cross-re active, binding 94 and 77%, respectively, of sera collected from HIV-1 individuals originating from various parts of the world. Even HIV-1-p ositive sera from some East African residents, infected by strains who se V3 loop sequences are undoubtedly distinct from the North American/ European consensus V3 loop sequence, reacted better to the V3 North Am erican/European consensus peptide than to African-specific V3 sequence s. Results indicate that the V3 consensus sequences represent the best candidates for optimal cross-reactivity with a wide variety of strain s. Furthermore, using immunoassays for antibodies to prototype-specifi c V3 sequences, it is shown that HIV-1 strains related to the MN group are prevalent in West Africa, indicating either a West African origin of the MN-related viruses or more probably an introduction of this gr oup of viruses through European/North American contacts.