IL1B and chorioamnionitis: Intra-amniotic injections in fetal sheep of IL-1 or E. coli endotoxin lipopolysaccharides (LPS), but not IL-6, IL-8, or TNF-α, induce chorioamnionitis and early lung maturation as measured by large increases in pressure–volume curves and lung mechanics and gas exchange within 5 to 7d (59–61).