RB6-8C5 activation of leukocytes/neutrophils in vivo but not in vitro.

(A) Positional changes of rolling leukocytes were determined every 40 video frames commencing at the time of RB6-8C5 application and continuing for 1 minute. Velocity = 0 indicates arrest of the cells. (B) Changes in blood flow induced by control treatments. Black diamonds represent mice receiving anti–L-selectin mAb (Mel-14) in place of RB6-8C5; red squares represent mice receiving anti–PSGL-1 mAb 2PH1 in place of RB6-8C5. Green circles represent mice receiving anti–Fcγ receptor II/III antibody 100 μg intravenously) followed 5 minutes later by RB6-8C5. Data are shown as means ± SEMs of 4 to 6 mice per group. (C-D) Effect of RB6-8C5 on CD11b expression of neutrophils from saline (C) and TNF-α–stimulated (D) mice. Filled histogram indicates autofluorescence, black line, isotype control for CD11b mAb; blue line, basal CD11b expression; green line, CD11b expression after RB6-8C5 treatment; red line, CD11b expression after PMA (positive control) treatment. Figures are representative of data obtained in 3 separate experiments.