Differentiation processes of connective tissue mast cells in living mice.

Mice of mutant genotypes were used to investigate the differentiation process of connective tissue mast cells. Mast cell precursors, which are a progeny of the multipotential hematopoietic stem cell, leave the bone marrow, migrate in the bloodstream and enter into connective tissues where they proliferate and differentiate into mast cells. A portion of morphologically identifiable mast cells may function as committed and localized mast cell precursors. When local production of mast cells is demanded, the mast cells with proliferative potentiality respond first. Further demand is met by invasion and differentiation of marrow-derived precursors.