Binding of A phagocytophilum to murine PSGL-1^-/- and wild-type leukocytes. Flow cytometric analysis of PE-conjugated anti-PSGL-1 mAb 2PH1 binding to PSGL-1^-/- or control neutrophils (A) and lymphocytes (B). Flow cytometric analysis of Cell Tracker Green-labeled, PFA-fixed A phagocytophilum binding to lymphocytes and neutrophils from PSGL-1^-/- (C) or control (D) mice. In panel D, control neutrophils were also pretreated with anti-murine PSGL-1 mAb 4RA10. Assays were performed in triplicate. Data are presented as the mean percentage (± SD) of leukocytes bound by 2PH1 or bacteria. CHO cells were used as a negative control in all experiments. Representative data from at least 2 studies are shown.