Figure 2.

Emergency monopoiesis. Under emergency or stress conditions, functionally distinct monocyte subsets may arise in the bone marrow or spleen, and production of monocyte (and other myeloid cell) subsets may be selectively enhanced. (A) In response to intestinal T. gondii infection in mice, MHCII⁺ Sca-1⁺ CX3CR1⁻ Ly6C^hi monocytes are produced by monocyte-committed progenitors that, unlike their steady-state counterparts, also express MHCII and Sca-1 (40). (B) LPS and CpG promote monocyte production by murine GMPs and MDPs, respectively; LPS also stimulates neutrophil production by GMPs, whereas CpG enhances cDC production by MDPs (11).