FIG. 5.
Anti-peptide 25 Ag (from MPT59)-induced proliferation of and IL-2 production by CD4+ T cells from IL-10−/− mice. IL-10−/− mice with a B6 background received a single dose of 200 μl of control vehicle (cream only; open bars), 104 CFU of live M. avium subsp. paratuberculosis in cream (hatched bars), or 104 CFU of heat-killed M. avium subsp. paratuberculosis in cream (solid bars) and were maintained under otherwise germfree conditions. CD4+ lymphocytes derived from the MLN and PP of the mice were purified and cultured at a density of 5 × 106 cells/ml with peptide 25 (1 μg/ml) for 3 days with γ-irradiated APCs (106 cells/ml). Cytokines present in culture supernatants were determined by ELISA. Proliferation was measured by BrdU incorporation. The data presented are the mean OD450 values for proliferative responses and the mean concentrations of IL-2 secretion (pg/ml) ± SD for quadruplicate cultures. Asterisks indicate statistically significant differences, i.e., P < 0.01, compared to controls. Experimental groups consisted of 15 mice each, and experiments were repeated three times.