Fig. (4) COX-2 activity influences IFN-γ and IL-12p70 production in antigen stimulated cultures of DO11.10 CD4+ T cells. Peritoneal macrophages were isolated and cultured in the presence of medium alone (A) or viable Salmonella(B). Following exposure for 45 minutes, cells were washed to remove any extracellular bacteria with gentamicin-containing medium. Magnetically separated splenic DO11.10 CD4 + T cells, B cells, and OVA peptide were added. To assess the role of COX-2, some cultures were supplemented with 1 uM celecoxib 20 minutes prior to infection. Levels of IFN-γ (A and B) and IL-12p70 (C) in 48-hour supernatants were measured by enzyme immunoassay, and are reported as mean values of triplicate determinations. These studies were performed three times with similar results.