FIG. 5.

Synergistic effect of MDP with LPS on induction of IL-8 secretion in U937 cell cultures. OCT-differentiated U937 cells were stimulated with MDP plus S. abortus-equi LPS at the indicated concentrations in triplicate. The IL-8 levels in the culture supernatants were determined by ELISA, and the mean values are shown. ∗∗ and ##, P < 0.01 versus control; #, P < 0.05 versus control. A significant (P < 0.01) synergistic effect of MDP and LPS on IL-8 production was detected by ANOVA including an interaction term. The results are representative of two different experiments.