monocyte non-classical monocyte https://cellxgene.cziscience.com/cellguide/CL_0000875 patrolling monocyte Markers: CCR2-CX3CCR1+ (human, mouse, rat); human: CD16+, CCR5+, CD32/FcgRII-high, MHCII+, CD86+; mouse: CD62L-Ly6C-. resident monocyte A type of monocyte characterized by low expression of CCR2, low responsiveness to monocyte chemoattractant CCL2/MCP1, low phagocytic activity, and decrease size relative to classical monocytes, but increased co-stimulatory activity. May also play a role in tissue repair. Non-classical monocytes, also known as patrolling monocytes, are a subtype of monocytes in the circulation, accounting for approximately 5-10% of total human monocytes. These monocytes are characterized by the differential expression of two surface markers, CD14 and CD16, with non-classical monocytes expressing CD14 and high levels of CD16 (CD14+ CD16++). Classical monocytes are released from the bone marrow into the circulation and can transition to intermediate followed by non-classical monocytes. Non-classical monocytes patrol the endothelium and, upon sensing inflammation or injury, migrate across it. Non-classical monocytes are also involved in the removal of damaged cells via phagocytosis. This process enables the cells to engulf and destroy pathogens, debris, and apoptotic cells. During homeostasis, these monocytes appear to have an important function in maintaining vascular integrity. Non-classical monocytes are also able to induce CD4+ T cell proliferation and sense viruses. They can produce and secrete a wide range of inflammatory cytokines and chemokines to reinforce and shape the immune response. Non-classical monocytes also appear to play a role in different inflammatory diseases states including atherosclerosis, multiple sclerosis, and rheumatoid arthritis. (This extended description was generated by ChatGPT and reviewed by the CellGuide team, who added references, and by the CL editors, who approved it for inclusion in CL. It may contain information that applies only to some subtypes and species, and so should not be considered definitional.)