A novel epitope R7V common to all HIV-1 isolates is recognized by neutralizing IgG found in HIV-infected patients and immunized rabbits

We have previously reported that the presence of antibodies (Ab) directed t o the beta 2-microglobulin-derived peptide R7V in patient's serum correlate d with the nonprogression to AIDS. In order to investigate whether R7V moti f could represent a potential target for neutralization, we have immunopuri fied anti-R7V Ab from sera of nonprogressors, as well as from sera of rabbi ts injected with R7V. We showed that human as well as rabbit purified anti- R7V Ige precipitated laboratory adapted strains. as well as primary isolate s From different clades indicating that. (1) R7V epitope is a common motif presented at the surface of genetically divergent HIV-I strains (2) R7V is immunogenic in vivo. When used in neutralizing assay, purified anti-R7V Ab from human or rabbit origin were shown to neutralize infection by HIV-1 lab oratory adapted strains and HIV-I primary isolates. All together, our resul ts indicate that the R7V motif shared by all HIV strains could be considere d as a possible candidate for an HIV vaccine. (C) 1999 Elsevier Science Ltd . All rights reserved.