LYSIS OF HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 ANTIGEN-EXPRESSING CELLSBY CD4 AND CD8 T-CELLS EX-VIVO

The aim of this study was to investigate the extent of lysis mediated by cytotoxic T lymphocytes (CTL) directed against human immunodeficien cy virus (HIV) type 1 gag protein and envelope glycoprotein in periphe ral blood mononuclear cells (PBMC) from HIV-1-infected subjects and to compare it with nonspecific envelope glycoprotein-directed cytotoxici ty involving CD4 T cells. Most seropositive subjects exhibited antigen -specific cytotoxicity directed at one or both viral antigens in unsti mulated or in vitro-stimulated PBMC (or both) mediated by CD8 T cells. In addition, all donors, including seronegative control persons, exhi bited nonspecific calcium-independent cytotoxicity involving CD4 T cel ls and envelope glycoprotein-expressing cells. No calcium-dependent, a ntigen-specific CD4 T cell-mediated cytolysis was detected. In seropos itive subjects, the vigor of nonspecific cytotoxicity was comparable t o lysis by antigen-specific CD8 CTL and suggests that it may contribut e to lysis of HIV-infected cells in vitro and in vivo.