FIG. 3.

Recombinant TNF-α and IL-18 induce macrophage MMP activity. Macrophage monolayers were incubated in medium alone or with increasing concentrations of recombinant murine TNF-α for 24 h (A) or 72 h (B) or with recombinant murine IL-18 for 72 h (C). Cell culture supernatants were analyzed for gelatinase activity using zymography. No MMP activity could be detected in IL-18-stimulated cultures by 24 h. Data presented are representative of three to five independent experiments.