Antigen-specific and polyclonal cellular immune responses were higher in anti-FasL–treated animals compared with controls. (A) Gag-specific responses were measured by IFNγ ELISPOT. There were higher antigen-specific responses in the anti-FasL group at weeks 4 and 6 after infection compared with controls. (B) The SIV Gag-specific responses, measured as the percentage of IFNγ-producing CD4⁺ T cells detectable by intracellular flow cytometry, were also higher in anti-FasL–treated animals at 4 weeks after infection. (C) Significantly higher percentages of IFNγ⁺ CD4 and CD8 lymphocytes were detected in response to polyclonal stimulation in anti-FasL–treated animals at 4 weeks after SIV challenge. *P < .05. Error bars indicate SEM.