Figure 8.

CR3-mediated phagocytosis is a silent entry pathway into neutrophils.

Non-opsonized substrates that are phagocytosed into neutrophils via CR3 do not induce the oxidative burst, poorly activate inflammatory signaling cascades, and predominantly reside in immature phagosomes. While this pathway of silent entry would facilitate non-inflammatory clearance of iC3b-tagged apoptotic cells and immune complexes (recapitulated in this study by use of iC3b-coated polystyrene beads), it is exploited by diverse microbes, including Neisseria gonorrhoeae and Mycobacterium smegmatis, to avoid degradation and killing within neutrophils.