Bah interferon [gamma] (IFN-[gamma]) produced by T helper 1 ([T.sub.H]1) lymphocytes and inteleukin- produced by [T.sub.H]2 lymphocytes were reduced in either bulk circulating mononuclear cells or mitogen-induced CD4+ T cell clones from the peripheral blood of individuals infected with human immunodeficiency virus (HIV). There was a preferential reduction in clones producing IL-4 and IL-5 in the advanced phases of infection. However, enhanced proportions of CD4+ T cell clones producing both [T.sub.H]1-type and [T.sub.H]2-type cytokines ([T.sub.H]0 Clones) were from either skin-infiltrating T cells that had been activated in vivo or peripheral blood T cells stimulated by antigen in vitro when cells were isolated from HIV-infected individuals. All [T.sub.H] and most [T.sub.H]1 clones supported viral replication, although viral replication was not detected any of the [T.sub.H]0 clones infected in vitro woth HIV. These results suggest that HIV (i) does not induce a definite [T.sub.H]1 to [T.sub.H]2 switch, but can favor a shift to the [T.sub.H]0 phenotype recall antigens, and (ii) preferentially replicates in CD4+ T cells producing [T.sub.H]2-type cytoki ([T.sub.H]2 and [T.sub.H]0).