IFN-γ deficiency modulates the PMN infiltration in SES-induced peritoneal inflammation. (a) Wild-type and IFN-γ–/– mice were intraperitoneally administered with PBS, SES, or SES in combination with IFN-γ (50 U per mouse). At defined time points, PMN infiltration was assessed using differential cell counting (*P < 0.05, a significant increase versus IFN-γ–/– plus SES; #P < 0.05, a significant decrease versus IFN-γ–/– plus SES). (b) KC levels were quantified by ELISA (*P < 0.05, a significant increase versus IFN-γ–/– plus SES). Results are expressed as the mean ± SEM of 10 mice per treatment. (c) The rate of PMN infiltration in response to exogenous administration of IFN-γ (0.5–500 U per mouse) to IFN-γ–/– mice. Filled circles represent IFN-γ–/– mice receiving SES in combination with defined doses of IFN-γ. The open circle illustrates the rate of PMN infiltration in wild-type mice.