HUMAN-IMMUNODEFICIENCY-VIRUS GLYCOPROTEIN-SPECIFIC CD4(-LYMPHOCYTES ARE INVOLVED IN 2 TYPES OF CYTOTOXICITY - ANTIGEN-SPECIFIC AND CELL-CELL FUSION-RELATED CELL-LYSIS() CYTOTOXIC T)

Human immunodeficiency virus (HIV) glycoprotein-specific CD4(+) cytoto xic T lymphocytes (CTLs) lyse target cells in an MHC-restricted calciu m-dependent fashion similar to the mechanism used by CD8(+) CTLs. Howe ver, contact of unprimed peripheral blood CD4(+) T cells with HIV glyc oprotein-expressing cells has been shown to cause, in addition to cell -cell fusion, rapid cytolysis that may resemble antigen-specific cytot oxicity in the chromium release assay, In this study, the ability of g lycoprotein-specific CD4(+) CTLs to undergo similar fusion-related cyt olysis was examined, The data obtained demonstrate that in addition to antigen-specific calcium-dependent cytotoxicity, envelope-specific CD 4(+) CTLs are involved in fusion-related, calcium-independent cytolysi s.