Infused, negatively charged, immune-modifying microparticles ( IMPs ), derived from polystyrene, microdiamonds, or biodegradable poly ( lactic-co-glycolic ) acid, are taken up by inflammatory monocytes, in an opsonin-independent fashion, via MARCO . This results in monocyte sequestration in the spleen through apoptotic cell clearance mechanisms.
32.
Phagocytosis of such cells requires specific receptors on the phagocyte that recognise either phosphatidylserine directly or opsonins bound to the phosphatidylserine or other " eat-me " signals, such as calreticulin . " Don't-eat-me " signals include CD47, which when expressed on the surface of a cell, inhibit phagocytosis of that cell, by activating SIRP-alpha receptors on the phagocyte.
