THE EFFECT OF DELETION OF THE V3 LOOP OF GP120 ON CYTOTOXIC T-CELL RESPONSES AND HIV GP120-MEDIATED PATHOGENESIS

New strategies for improving the efficacy of IPN vaccines are of signi ficant importance. In this study, we analyzed the effect of deletion o f the hypervariable V3 loop of gp120 on envelope (env)-specific CTL re sponses in PBMC of RN-infected individuals. We showed increased CTL ac tivities against conserved epitopes of the env glycoprotein in culture s induced with the Delta V3 mutant compared with those stimulated with the full-length env gene products. In contrast to the wild-type env, the Delta V3 mutant-expressing cells were resistant to Ah-dependent ce ll-mediated cytotoxicity, formed no syncytia, and neither underwent no r induced apoptosis in CD4(+) cells, Thus, the Delta V3 mutant may red ia ece immune responses toward conserved epitopes of gp160, has longer expression time due to increased resistance to Ah-dependent cell-medi ated cytotoxicity, and does not trigger cytopathic effects associated with apoptosis and syncytium formation. This approach may apply to oth er Ags of HIV, where deletions of highly variable or immunosuppressive epitopes may improve the efficacy of HIV vaccines.