Effect of rPSGL-Ig treatment on leukocyte-tethering rate.

WT mice were prepared for intravital microscopy, and surgically induced leukocyte rolling was allowed to develop for 10 minutes. Attention was focused on regions where new tethers could be clearly distinguished, and control tethering rate was determined for 5 to 10 minutes. Low-dose (1 mg/kg) rPSGL-Ig was then injected intravenously, and tethering determined for a further 5 to 10 minutes. Anti–P-selectin antibody was injected at the end of experiments as a positive control. Tethering rates were determined in 6 mice for each dose of rPSGL-Ig studied. Significant difference from control is indicated by **P < .01. Data are presented as mean ± SEM.