Figure 5. Nod1 and Nod2 contribute to bacteria-induced TNF-α production and NF-κB activation in macrophages infected with MNV-1.

(A and B) BMDMs from WT and Nod1^−/−Nod2^−/− mice were left untreated, treated with poly I:C, or infected with MNV-1 for 24 h and then infected with live E. coli (A) or P. aeruginosa (B) at a bacteria/macrophage ratio (B/M) of 1, 5, and 10. Cell-free supernatants were analyzed for production of TNF-α (* p < 0.05, ** p < 0.01, *** p < 0.001, compared with WT and mutant macrophages cultures). (C) BMDMs from WT and Rip2^−/− mice were left untreated, treated with poly I:C, or infected with MNV-1 for 24 h and then infected with live E. coli or P. aeruginosa at a bacterial/macrophage ratio (B/M) of 1. Cell free supernatants were analyzed for production of TNF-α (* p < 0.05, ** p < 0.01, compared with WT and mutant macrophages cultures). (D) BMDMs from WT and Nod1/Nod2^−/− mice were left untreated or treated with poly I:C or infected with MNV-1 for 24 h and then infected with E. coli at bacteria/macrophage ratio of 10 for the indicated times. Cell extracts were assessed for MAPK, NF-κB activation and α-tubulin levels by immunoblotting. Data are expressed as mean ± S.D. Results are representative of 3 independent experiments