Fig. 11. PrP^C expressed by monocytes and endothelial cells is involved in transmigration of freshly isolated monocytes. Freshly isolated monocytes were labeled as above and separately incubated (monocytes) with anti-CD71, anti-PECAM-1 or anti-PrPC antibodies at 20 µg/ml for 1 hour, as indicated. Similarly, hCMEC/D3 endothelial cells, grown and activated as above, were separately incubated in the same conditions (hCMEC/D3). In parallel, both monocytes and hCMEC/D3 endothelial cells (monocytes + hCMEC/D3) were separately incubated in the same conditions. Monocytes were then added to the apical compartments of Transwell filters and allowed to transmigrate for 3 hours in the presence of MCP-1 (25 ng/ml) in basal compartments, as above. Average values (± s.e.m.) from one representative experiment out of three independent experiments are presented. The number of migrated cells following incubation with CD71 antibodies was taken as 100% in each condition (*P<0.01 versus cells pre-treated with anti-CD71 antibody).