Macaca nemestrina efficiently control acute human immunodeficiency virus type 1 (HIV-1) infection. The roles of helper (Th) and cytotoxic (CTL) T cells in controlling acute HIV-1 infection in both peripheral blood and lymph node mononuclear cells (PBMC and LNMC) were assessed in this model. Th and CTL responses to HIV-1 were detected within 2 weeks following HIV-1 infection, and CTL responses to HIV-1 antigens peaked at 4 weeks after infection (>100 HIV-specific CTL/10[6] PBMC), coincident with reductions of HIV-1 RNA and DNA levels in peripheral blood. HIV-1-specific Th and CTL were present in LNMC 6 weeks after infection. Although HIV-1 antibodies were detected 2 weeks after infection, maximal HIV-1 antibody responses were not generated until > 13 weeks after inoculation. Thus, T cell responses temporally correlate with control of HIV-1 in macaques. The induction of a brisk HIV-1-specific CTL response may have been facilitated by a persistent Th response.