EFFECTIVE LYSIS OF HIV-1-INFECTED PRIMARY CD4(-CELLS BY A CYTOTOXIC T-LYMPHOCYTE CLONE DIRECTED AGAINST A NOVEL A2-RESTRICTED REVERSE-TRANSCRIPTASE EPITOPE() T)

Most HIV-specific cytotoxic T-lymphocyte (CTL) epitopes have been iden tified using peptide-pulsed and recombinant vaccinia virus-infected ta rgets. These systems may not accurately reflect the ability of epitope s to be presented by HIV-infected T cells. Recent studies suggest, in fact, that some CTL epitopes are poorly presented on HIV-infected cell s. In this study, we have identified a novel A2.1-restricted HIV rever se-transcriptase (RT) epitope and investigated the presentation of thi s epitope by HIV-infected primary CD4(+) T cells and T-cell lines. A C D8(+) CTL clone, isolated from a seropositive subject that recognized a novel A2-restricted epitope KYTAFTIPSI (aa 293-302) in RT, was used for these studies. Primary CD4(+) T cells and the CD4(+) T-cell line T 1 were infected with virus from T1-nPLAP, a cell line stably transfect ed with HXB-nPLAP, a molecular construct of HIV linked to a placental alkaline phosphatase (PLAP) marker gene. A uniformly infected cell pop ulation, obtained by immunomagnetic selection for FLAP expression, was used as targets in CTL assays. HIV-infected T cells were lysed by CTL recognizing this RT epitope as effectively as peptide-pulsed targets. This suggests that some RT epitopes are good targets for CTL recognit ion.