Effect of complement on LPS-induced cytokine production by splenocytes and peritoneal macrophages in vitro. (A) ELISA assays of IL-6 production by wild-type (WT) and DAF^−/− mouse splenocytes in culture. Splenocytes from LPS-challenged (30 minutes before harvest) mice were cultured for 3 hours in the presence or absence of C5a (50 nM) and C3a (200 nM). (B,C) ELISA assays of IL-6 (B) and TNF-α (C) production by WT and DAF^−/− mouse peritoneal macrophages in culture. Cells were stimulated by various concentrations of LPS for 5 hours. (D) ELISA assays of IL-6 production by WT and DAF^−/−/C3^−/− mouse peritoneal macrophages in culture. Cells were stimulated by 1000 ng/mL LPS for 5 hours. (E) ELISA assays of IL-6 production by WT mouse peritoneal macrophages stimulated for 5 hours with LPS (100 or 1000 ng/mL) in the presence or absence of C5a (50 nM) and C3a (200 nM). Cells from 4-5 mice were pooled and assayed in triplicate wells. Values shown are the mean ± SEM. *P < .05, **P < .01, Student t test.