Skip to main content
. Author manuscript; available in PMC: 2014 Aug 1.
Published in final edited form as: Curr Opin Pharmacol. 2013 Jun 7;13(4):555–564. doi: 10.1016/j.coph.2013.05.013

Figure 1.

Figure 1

Origin and development of the mononuclear phagocyte system. The mononuclear phagocyte system (MPS) encompasses monocytes, macrophages and dendritic cells (DC). The MPS is generated from hematopoietic stem cells (HSC) in the bone marrow, but a recent identified new lineage of macrophages (F4/80+) develops from the yolk sac before the appearance of HSCs. These macrophages traffic to epithelial tissues to become permanently residing cells, e.g., Kupffer cells, Langerhans cells or microglia. Subsets are also found in kidney, spleen and lungs. Bone marrow precursors are differentiated into the macrophage and DC common progenitors (MDP) that give rise to common DC progenitors (CDP) or monocytes. CDPs further commit to plasmacytoid DCs or preDCs resulting in DCs. Monocytes are able to give rise to macrophages or DCs. In steady state conditions Ly6Clow monocytes remain around the vascular endothelium. In inflammation Ly6C high monocytes are recruited and differentiate into inflammatory macrophages. The spleen supplies Ly6Chigh monocytes to inflamed heart after myocardial infarction.