Figure 2.

Synergism between TLRs and C5aR in peritoneal macrophages but not in peritoneal mesothelial cells enhances pro– and anti–inflammatory and fibrotic mediator release. Levels of proinflammatory cytokines and fibrotic markers in the culture supernatants of (A, C, and D) PDE–isolated resident peritoneal leukocytes or (B) peritoneal mesothelial cells (from omentum) stimulated overnight with the indicated concentrations of Pam₃Cys (or 250 ng/ml), LPS (or 1 ng/ml), or heat–killed E. coli in the presence or absence of increasing concentrations of C5a. In C, cells were preincubated with an anti–C5L2 blocking mAb (1D9; 5 μg/ml). IL-8, IL-13, TGF-β, and TIMP-1 levels were determined by ELISA, and IL-6, IL-10, TNF-α, MMP-1, MMP-3, and MMP-9 levels were determined by multiplex ELISA (Meso Scale Discovery). Results are from one experiment (±SD) representative of (A and B) 10 or (C and D) five performed with cells from different donors. The P values indicate statistical significance for the comparison between the additive response to a TLR agonist alone and C5a alone and the response to the combination of TLR agonist and C5a. *P<0.05; **P<0.01; ***P<0.01.