Development, differentiation, and phenotypic heterogeneity of murine tissue macrophages

Abstract: In murine ontogeny, macrophage pre-cursor cells develop in the yolk sac and fetal liver. Primitive macrophages also appear in the yolk sac, migrate to various tissues, and differentiate into several fetal macrophage populations. Because the development of the monocytic cell lineage is incom-plete in the early stage of fetal hematopoiesis, primi-tive/fetal macrophages are considered to originate from granulocyte-macrophage colony-forming cells or earlier macrophage precursors, bypassing the early monocytic cell series. In adult mice rendered severely monocytopemc by administration of stron-tium-89, resident macrophages are maintained by self-renewal. In contrast, administration of liposome-encapsulated dichioromethylene diphosphonat