SIRPα in activated monocytes and macrophages mediate high avidity cell adhesion to immobilized CD47.

<p>To obtain activated monocytes, freshly isolated PMBC were treated with 50 ng/ml MCP-1 (37°C, 1 h) and were also induced to transmigrate across HMEC-1 endothelial monolayers by MCP-1. To obtain macrophages, THP-1 cells were treated with PMA (50 nM) for 3-4 days. A) Cell adhesion assays. SE5A5 and SE7C2 are both inhibitory anti-SIRPα mAbs. B) Percentage of cell adhesion to CD47-AP versus BSA. ***, <i>P</i> <0.001. C) FACS analysis of SIRPα on the surface of naïve (PBMC) and activated monocytes, unstimulated and stimulated THP-1 using anti-SIRPα.ex antibody.