FIG 6.

IL12Rβ1ΔTM potentiates IL-12 responsiveness in an environment where IL-12 is limiting. Mononuclear cells were purified from the spleens of C57BL/6, ΔTM^−/−, and il12rb1^−/− mice, normalized for cell number, and cultured in the presence of ConA (1 μg/ml) and increasing concentrations of IL-12 (i.e., 0, 0.005, 0.05, 0.5, 5, and 50 ng/ml). At 24 h later, the supernatants of each culture condition were clarified and used to measure IFN-γ levels by enzyme-linked immunosorbent assay. Shown for each IL-12 concentration are the means ± the standard deviations for the IFN-γ levels produced by C57BL/6 splenocytes (●), ΔTM^−/− splenocytes (○), and il12rb1^−/− splenocytes (■). Significant differences between ΔTM^−/− mice and either C57BL/6 or il12rb1^−/− controls are indicated by an asterisk (P ≤ 0.05, Student t test). The data are representative of four separate experiments.