TNF and infection: Compared to 0 h, lethally infected mice showed significant increases in the levels of 14 out of the 21 chemokines/cytokines measured in the peritoneal lavage fluid at 4 h p.i. (Fig. 5) whereas the sublethal infection induced a transient elevation in the level of IL-1α, IL-1β, IL-6, KC, MCP-1, MIP-1β and TNF-α in the peritoneal lavage fluid; these levels peaked at 4 h p.i. and generally returned to the baseline level by 48 h p.i. (Fig. 5).