Nitrite production by (A) resident peritoneal macrophages and (B) thioglycollate-elicited peritoneal macrophages from WT and βc-null mice in response to saline or IFN-γ/LPS after 48 hours of incubation. Mean of 4 to 5 wells. Error bars represent SD. Results shown are for two mice per genotype. Five experiments performed with similar results.