Shedding of L-selectin is required for bacterial clearance in the tissue during K pneumoniae–induced pneumonia. (A-L) ADAM17^+/+ and ADAM17^−/− mice, as well as WT and L(E) mutant mice, were subjected to K pneumoniae intratracheal injection. Bacterial burden, as reflected by CFU in blood (A,G), lung (B,H), BALF (C,I), and spleen (D,J), as well as neutrophil recruitment into the alveoli (E,K) and lung tissue (F,L), were determined 24 hours after K pneumoniae injection. n = 7 mice per genotype. Data are mean ± standard error of the mean. *P = .05, **P = .01, ***P = .001, Student t test.