Mice lacking IL-4 displayed impaired resolution of sterile inflammation. (A) Inflammation induced by sodium periodate in Il4^−/− and WT mice was scored by determining cell counts at day 0, day 3, and day 4. (B) Cell populations were compared between Il4^−/− and WT mice on day 3. (C) Peritoneal CD4 T cells isolated from day 4 Il4^−/− or WT mice were ex vivo–stimulated with anti-CD3 and anti-CD4 for 24 hours. IL-4, IL-13, and IFN-γ in supernatants were measured by ELISA. (D) WT splenic NKT cells were adoptively transferred into WT or Il4^−/− mice 66 hours after intraperitoneal injection of sodium periodate; peritoneal cell numbers in recipient mice were enumerated as described in Figure 3H. (E) CD4+ T cells isolated from recipient mice in (D) were stimulated and cytokine profile was examined as in Figure 3I. (F) WT or Il4^−/− day 3 PEM were co-cultured with WT splenic NKT cells for 48 hours before IL-4 and IFN-γ in supernatants were measured by ELISA. PMN, polymorphonuclear leukocytes.