CD8(+) T-cell gamma interferon production specific for human immunodeficiency virus type 1 (HIV-1) in HIV-1-infected subjects

wThe CD8(+)-T-cell response to human immunodeficiency virus type 1 (HIV-1) is considered to be important in host control of infection and prevention o f AIDS. We have developed a single-cell enzyme immunoassay (enzyme-linked i mmunospot assay) specific for gamma interferon (IFN-gamma) production stimu lated by either autologous B-lymphoblastoid cell lines (B-LCL) infected wit h vaccinia virus vectors expressing HIV-1 proteins or synthetic peptides re presenting known HIV-1 CD8(+) cytotoxic T-lymphocyte (CTL) epitopes. Single -cell IFN-gamma production stimulated by HIV-1 Gag-, Pol-, and Env-expressi ng B-LCL was a reliable measure of HIV-1-specific T-cell immunity in periph eral blood CD8(+) T cells from HIV-1 infected individuals. This method was more sensitive than stimulation of IFN-gamma by direct infection of the cul tures with HIV-1-vaccinia virus vectors. Comparable results were found for IFN-gamma production in CD8(+) T cells from HIV-1-negative, cytomegalovirus (CMV)-seropositive, healthy donors stimulated with B-LCL expressing the CM V pp65 lower matrix protein. HIV-1 peptides were immunodominant for both CD 8(+) single-cell IFN-gamma production and CTL precursor frequencies. The nu mber of cells producing IFN-gamma decreased in individuals with late-stage HIV-1 infection and was temporally enhanced during combination antiretrovir al therapy with two reverse transcriptase nucleoside inhibitors and a prote ase inhibitor.