Induction of CD4⁺ human cytolytic T cells specific for HIV-infected cells by a gp160 subunit vaccine

Cytolytic T lymphocyte (CTL) responses were evaluated in humans immunized with recombinant human immunodeficiency virus type 1 (HIV) envelope glycoprotein gp160. Some vaccinees had gpl60-specific CTLs that were shown by cloning to be CD4⁺. Although induced by exogenous antigen, most gpl60-specific CTL clones also recognized gp160 synthesized endogenously in target cells. These clones lysed autologous CD4⁺ T lymphoblasts infected with HIV. Of particular interest were certain vaccine-induced clones that lysed HIV-infected cells, recognized gpl60 from diverse HIV isolates, and did not participate in "innocent bystander" killing of noninfected CD4⁺ T cells that had bound gpl20.