Inhibiting IL-1β protects fetal airway development from the effects of LPS. E15 fetal lung explants from C57BL/6 mice were cultured in the presence of LPS (250 ng/ml) along with (A) nonimmune IgG, (B) neutralizing antibodies against IL-1β (10 ng/ml), (C) neutralizing antibodies against TNFα (10 ng/ml), or (D) both IL-1β and TNFα antibodies. Brightfield images from representative explants illustrate airway formation between 24–72 h of culture. (E). LPS inhibits airway formation, but antibodies against IL-1β prevented this inhibition (*P < 0.05, n = 18–53). Anti-TNFα had no effect. (F). Antibodies against IL-1β and TNFα did not prevent the initial inflammatory response, as measured by Ccl2 expression (*P < 0.05, n = 5).