Role of IL-18 and T-bet in IFNγ production in vitro. A.) Neutrophils (CD45+/CD11b+/Ly6G+/NK1.1-) were sorted from the lungs of WT mice exposed to S. rectivirgula one time. The cells were stimulated overnight with IL-12 (10 ng/ml), IL-15 (20 ng/ml) or IL-18 (20 ng/ml) alone or in combination. Culture supernatants were collected and IFNγ measured by ELISA. B.) Spleen cells were isolated from WT or T-bet-/- mice and stimulated overnight with S. rectivirgula (10 μg); IFNγ was measured in cell culture supernatants by ELISA.