Table 1.

Macrophage subsets and their functions

Macrophage Phenotype		Inducers	Secretions	Expressed Markers	Functions	References
M1		LPS, IFN-γ	iNOS, IL-1β, IL-6, IL-12, IL-15, IL-18, TNF-α, CCL-15, -20, CXCL-9, -10, -11	MHCII, CD86, TLR, IFN-γR	Phagocytose bacteria and debris, attract immune cells, tissue damage, clearance of intracellular pathogens, pro-inflammatory	(8–12)
M2	M2a	IL-4, IL-13, IL-33	IL-10, IL-12, CCL-13, -14, -17, -18, 22, 23, 24, 26, IGF-1, arginase, FIZZ1, YM1	MR, GR, SR, CD 163, CD23	Support ECM deposition wound closure, angiogenesis, promotion of allergic responses, anti-inflammatory	(13–15)
	M2b	Immune complexes, IL-1β, LPS	IL-10, CCL-1, -20, CXCL-1, -2, -3	IL-1R, IL-10R, TLR4, FcγR	Suppress inflammation via high IL-10, immuneregulation,	(16–19)
	M2c	IL-10, GC, TGF-β	CCL-16, 18, CXCL-13, TGF-β, BMP-2	CD163, CD206, IL-10R, PD-1	Suppress inflammation via IL-10, produce ECM and MMPs for vascular/matric remodeling, tissue remodeling	(20–22)
	M2d	IL-6 and adenosine	VEGF, IL-10, IL-12, TNF-α, TGF-β	---	Aids in angiogenesis via VEGF	(23–25)