T cell recognition of common and type-specific herpes simplex virus (HSV) glycoproteins was measured in 72 subjects, T cells were stimulated with whole HSV-2 antigen and glycoproteins gB2, gD2, and gG2. T cell proliferation in response to HSV-2 antigen and gG2 was significantly higher in subjects with HSV-2 infection than in those with HSV-1 infection only; responses to gB2 and gD2 were the same. T helper (Th) type 1 and Th2 cytokine production in response to whole HSV-2 antigen, gB2, and gD2 was evaluated in 33 subjects, Interleukin (IL)-2 and interferon-gamma responses to most antigens were significantly higher among HSV-2-seropositive subjects than among seronegative subjects, IL-4 synthesis was negligible; IL-10 was produced in seronegative and seropositive persons, but HSV-2 antigen responses were significantly higher in HSV-2-seropositive persons, Naturally acquired immunity to HSV involves T cell recognition of common and type-specific glycoproteins, prominent Th1 responses, and discordant Th2 responses with little IL-4 but substantial IL-10 production.