Suppression of MMP-2 by CoMTb is mediated by TNF-α. (A), CoMTb was preincubated with increasing doses of anti-TNF-α Ab for 2 h. (B), TNF-α suppresses MMP-2 secretion. Cells were stimulated with rhTNF-α 1-100 ng/ml. Note representative gelatin zymogram has been cut to correspond to the adjacent graph (thick black line). (C), IL-1β does not contribute to CoMTb induced MMP-2 secretion. Cells were preincubated with IL-1Ra for 2 h. Inhibition of IL-1β activity did not affect MMP-2 secretion. (D), IL-1β alone does not suppress MMP-2 secretion. Microglial cells were stimulated with rhIL-1β at concentrations of 1-100 ng/ml. Densitometric analysis of gelatin zymography is shown with a representative gelatin zymogram for A-D. For all experiments bars represent mean values ± SD of three samples, representative of at least duplicate experiments performed in triplicate. Data were analyzed by one-way analysis of variance followed by Tukey's multiple comparison. *p < 0.05, **p < 0.01.