Fig. (5) COX-2 activity influences IFN-γ production in IL-12 stimulated cultures of BALB/c CD4+ T cells. IFN-γ production by CD4 + T cells in the presence or absence of celecoxib was evaluated. 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 BALB/c CD4 + T cells were added and cultured in the presence of IL-12 and/or celecoxib. Results are presented as mean values of triplicate determinations. These studies were performed twice with similar results.