Leukocyte adhesion was impaired in the absence of mAbp1 under flow conditions in vivo. Adhesion of mAbp1^+/+ and mAbp1^−/− PMNs under static conditions on immobilized (A) fibrinogen or (B) ICAM-1 30 minutes after treatment with TNFα (100 ng/mL) or Mn²⁺ (1 mM). Data represent adhesion in percentage of cells adherent to poly-l-lysine (100%). Means ± SDs; mAbp1^+/+, n = 5; mAbp1^−/−, n = 4; *P < .05 versus unstimulated control; n.s. indicates not significant. Intravital microscopic analysis of PMNs (C) rolling (leukocyte rolling flux fraction; mean percentage ± SEM) and (D) adhesion (means of adherent cells/mm² ± SEMs) in TNFα-stimulated cremaster muscle venules of mAbp1^+/+ (□) and mAbp1^−/− mice (▩). (E) Cumulative frequency distribution of leukocyte rolling velocities in mAbp1^+/+ mice (black line) and mAbp1^−/− (gray line). (F) Quantitative analysis of intravascular and perivascular leukocytes in whole-mount TNFα-treated cremaster muscle preparations from mAbp1^+/+ mice (□) and mAbp1^−/− (▩). Means of cells/mm² ± SEMs; n = 5; *P < .05.