Binding of P-selectin and PSGL-1 to neutrophils and monocytes. Binding of the human–P-selectin IgM chimeric molecule and PSGL-1 to splenic neutrophils (Gr-1 gated) and splenic monocytes (F4/80 gated) was analyzed by flow cytometry. (A) Neutrophils from the spleens of β4GalT-I^+/– (open histogram) and β4GalT-I^–/– (filled histogram) mice. The dotted line shows negative control without the P-selectin–human IgM chimeric molecule. Results from 1 of 3 representative experiments are shown. (B) Monocytes from the spleens of β4GalT-I^+/– and β4GalT-I^–/– mice as in panel A. Results from 1 of 2 representative experiments are shown. (C) Mean fluorescence intensities of P-selectin binding and PSGL-1 expression in splenic neutrophils (Gr-1 gated; n = 3) and splenic monocytes (F4/80 gated; n = 2). Data are presented as means ± SEM.