DC were untreated, matured with LPS (1µg/ml for 4h) or treated with TNF-α (500U/ml for 4h). In addition, TNFα treated DC were pulsed for a further 4h with LPS (1µg/ml). DC were stained for cell surface expression of CD11c and intracellular IL-12 and analyzed by flow cytometry. Values in the first column represent the % of CD11c+ and IL-12+ cells.Data from a representative experiment (of 2 performed) are shown. Ova primed T-cells (>90% CD3+ by flow cytometry) were stimulated for 4 days with DC treated as above. DC were loaded with ova by pulsing 1 x 106 cells with 80 μg/ml of ova for 4h. The DC:T cell ratio was 1:20 in each test. The second column represents the proliferation of cells as measured by H3-thymidine incorporation. The third column IFN γ production as measured by CelELISA. Values are mean and SEM of 3 experiments.