FIG. 2.

IFN-γ production from spleen cells. IL-10^−/− mice (open bars) or wild-type mice (closed bars) were infected with BCG. Four weeks later, splenocytes were isolated and stimulated with mycobacterial antigens (PPD, upper graphs) or ConA (lower graphs). Cytokines present in the culture supernatants were measured at 24 h (IL-2) or 72 h (other cytokines) poststimulation. Results are the means (error bars are the standard deviations) of results from duplicate cultures of splenocytes from six individual mice per group. In the absence of stimuli (i.e., splenocytes plated in media alone) the cells did not produce the cytokines assayed above background levels. Results are representative of three individual experiments performed to test T-cell responses to PPD.