Triplicate wells of the 96-well microtiter plates, pre-coated with IFN-γ (A) or perforin antibody (B), IFN-γ antibody with male and female (C), or perforin antibody with male and female (D) were seeded with 105 PBMCs on days 0, 2, and 30 after relocation, stimulated with 1 μg of each of the mitogens for 32 h at 37°C, and then washed and stained with biotinylated secondary IFN-γ or perforin antibody. The total number of spot forming cells (SFCs) in each of the mitogen-stimulated wells was counted and adjusted to control medium as background. See the “Materials and methods” section for experiment details. P values <0.05 were considered statistically significant. Symbol: * p<0.05; **p<0.01.