Effects of EPCR in monocyte and neutrophil migration. Effects of anti-EPCR antibodies on the inhibition by protein C, ArhPC, and AphPC of chemoat tractant-induced migration of neutrophils (A) and monocytes (B). Experiments were performed in modified Boyden chambers using nitrocellulose micropore filters. Cells were pretreated either with protein C (PC), activated recombinant human protein C (ArhPC), or activated plasmatic human protein C (AphPC) alone or with protein C/APC and the function blocking anti-EPCR antibody RCR-252 or the nonblocking anti-EPCR antibody RCR-92 for 20 minutes, followed by washing. Then chemotaxis toward IL-8 (1 nM) (neutrophils) or fMLP (10 nM) (monocytes) was monitored. Results are given as the mean ± SEM of the migration index, which is the ratio of the distance of migration (μm) toward attractant and that toward medium. Random migration in the absence of attractant gradients was 38 556 ± 2.072 SEM μm(n = 9) and 36.726 ± 4.330 SEM μm (n = 3) for neutrophils and monocytes, respectively. Statistical analysis was performed using the Mann-Whitney U test after the Kruskal-Wallis test. *P < .05. n = 3 and n = 4 (for neutrophils-RCR-252). n.s. indicates not significant.