L-selectin contributes to the enhanced neutrophil infiltration in Hs2st^f/fTie2Cre⁺ mice. (A) LPS (1 μg per mouse) was injected into dorsal air pouches; and after 4 hours, infiltrated neutrophils were collected and quantified. A set of wild-type and Hs2st^f/fTie2Cre⁺ mice were injected intravenously with a blocking antibody to L-selectin (MEL-14) 1 hour before LPS injection. Each symbol represents a single mouse. (B) Effect of MEL-14 on neutrophil rolling velocity was assessed in vitro using flow chambers. Neutrophils were pretreated with either control IgG or MEL-14 and infused through the slides (n = 6). (C) The number of rolling neutrophils was quantified after pretreatment with either control IgG or MEL-14 (n = 6). Error bar represents SEM. (D) Binding of L-selectin-Fc fusion protein to wild-type or mutant lung endothelial cells was measured by flow cytometry. Black represents binding to wild-type cells; red, binding to Hs2st^f/fTie2Cre⁺ cells; and blue, binding to Ndst1^f/fTie2Cre⁺. The control sample was incubated only with anti–Fc-DyLight488 and is shown as filled gray histogram. ns indicates not significant.