The concentration of LTB4 in bronchoalveolar lavage fluid did not differ between saline-challenged WT (n=4), LTC4S-/-(n=5), and CysLT1-/- (n=5) mice and lipopolysaccharide-challenged WT (n=6), LTC4S-/-(n=6), and CysLT1-/- (n=6) mice 18 hours after challenge. (B) In the same mice, levels of cysLTs (LTC4/D4/E4) in the bronchoalveolar lavage fluid were higher in WT and CysLT1-/- mice after lipopolysaccharide challenge than in saline-challenged WT and CysLT1-/- mice. As expected, no cysLTs were detectable in bronchoalveolar lavage fluid from the LTC4S-/- mice after challenge with either saline or lipopolysaccharide. * P<0.05 differs vs. saline-challenged mice of the respective genotype, # P<0.05 differs vs. lipopolysaccharide-challenged WT mice, § P<0.05 differs vs. lipopolysaccharide-challenged CysLT1-/- mice. B4, cysteinyl leukotriene B4; C4/D4/E4, cysteinyl leukotriene C4/D4/E4; CysLT1-/-, mice congenitally deficient in the cysteinyl leukotriene receptor 1; LPS, lipopolysaccharide; LTC4S-/-, mice congenitally deficient in leukotriene C4 synthase; WT, wild type mice. The levels of LTB4 and cysLT are depicted as individual values with arithmetic means.