Relative number of α-GalCer-activated liver lymphoid cells secreting IFN-γ in Vα14 NKT-deficient mice, IL-12-deficient mice, and their respective controls injected i.p. with 1 μg of α-GalCer. One day after α-GalCer injection, lymphocytes were obtained from the liver according to the method described by Goossens et al. (33), and the relative number of cells secreting IFN-γ was determined by an enzyme-linked immunospot assay (32). Results are shown for Vα14 NKT-deficient (Jα281−/−) (A), IL-12-deficient (IL-12p40−/−) (B), and their respective control (WT) mice. The results reflect two separate experiments and are expressed as mean values ± SD of triplicate cultures.