Strength of LFA-1– and Mac-1–mediated adhesion. Neutrophils (3 × 106 cells/mL) and E3-ICAM cells (5 × 106 cells/mL) were stimulated with 1 μmol/L FMLP and sheared in a cone-plate viscometer at 200 s−1 either in the absence of any MoAb (LFA-1– and Mac-1–dependent adhesion) or in the presence of anti–LFA-1 MoAb R3.1 Fab (Mac-1–dependent adhesion), anti–Mac-1 MoAb h60.1 (LFA-1–dependent adhesion), or on addition of both R3.1 and h60.1 (LFA-1– and Mac-1–independent adhesion): (A) in normal HEPES buffer (media viscosity, 0.7 cp), or (B) in buffer containing 6% Ficoll (media viscosity, 1.7 cp). The percent neutrophils in heterotypic aggregates is reported in the 2 panels. (C) Adhesion efficiencies for the experiment described in (A) and (B). Error bars represent SEM from at least three independent experiments. *P < .05 with respect to the same treatment in the absence of Ficoll.
