IDENTIFICATION OF MULTIPLE HIV-1 CYTOTOXIC T-CELL EPITOPES PRESENTED BY HUMAN-LEUKOCYTE ANTIGEN B35 MOLECULES

Objectives: To identify HIV-1 cytotoxic T lymphocyte (CTL) epitopes pr esented by human leukocyte antigen (HLA)-B35 molecules that are associ ated with the accelerated progression of AIDS using a reverse immunoge netic approach. Methods: 8-mer to 11-mer sequences carrying two anchor residues at position 2 and the carboxy-terminus were selected from HI V-1(SF2) strain. Sixty-four peptides matched to these sequences were s ynthesized and tested by a peptide binding assay using RMA-S-B3501 ce lls. Peripheral blood lymphocytes (PBL) from two HIV-l-infected donors carrying HLA-B35 were stimulated once-weekly with each HLA-B3501 bin ding peptide. The CTL activity of the cultured cells for the HLA-B35-p ositive target cells loaded with the corresponding peptides was examin ed after the second and fourth stimulation. Furthermore, the CTL activ ity of the cultured cells possessing HLA-B3501-restricted HIV-1 pepti de-specific CTL activity were examined for the HLA-B3501-positive tar get cells infected with the recombinant vaccinia virus containing corr esponding HIV-1 gene. Results: HIV-1 peptide-specific HLA-B3501-restr icted CTL was induced in PBL of HIV-1 infected donors by in vitro stim ulation with 11 out of 27 HLA-B3501-binding HIV-1 peptides. The speci fic CTL induced with 10 peptides killed the cells infected with recomb inant vaccinia virus expressing the corresponding HIV-1 proteins. Out of these HIV-1 peptide epitopes, two epitopes were also presented by H LA-B51 molecules. Conclusion: In addition to the four HLA-B35-restrict ed HIV-1 CTL epitopes that have been previously reported, nine HLA-B35 -restricted HIV-1 CTL epitopes were identified in the present study. T hese multiple epitopes will be useful in studies for immunopathogenesi s of AIDS.