The anti-human immunodeficiency virus type I (anti-HIV-1) effects of -glutamylcysteine ethyl ester (-GCE; TEI-2306) were examined in vitro. In initial studies using a vigorously HIV-1-producing human T-lymphocytic cell line, -GCE displayed a novel biphasic repressive effect on chronic HIV-1 infection that was unlike that of other glutathione prodrugs or other reported antioxidants. In high doses, up to a concentration of 2.5 mM, at which neither glutathione (GSH) nor another GSH precursor has shown inhibitory effects, -GCE potently inhibited the production of HIV-1 by a selective cytopathic effect against infected cells, while the viability and growth of uninfected cells were unaffected at the same -GCE concentrations. At lower concentrations (200 to 400 µM), -GCE significantly repressed the virus production from chronically HIV-1-expressing cells without affecting their viability. The discrepancy of the thresholds of the toxic doses between infected and uninfected cells was found to be more than 10-fold. Relatively high doses of -GCE, utilized in acute HIV-1 infection of T-lymphocytic cells, entirely blocked the propagation of HIV-1 and rescued the cells from HIV-1-induced cell death. Furthermore, -GCE at such concentrations was found to directly inhibit the infectivity of HIV-1 within 4 h. Repressive effects of -GCE on acute HIV-1 infection in human primary human peripheral blood mononuclear cells were also demonstrated. Here, the anti-HIV-1 strategy utilizing -GCE is removal of both HIV-1-producing cells and free infectious HIV-1 in vitro, in place of specific immunoclearance in vivo, which might lead to an arrest or slowing of viral propagation in HIV-1-infected individuals.