Transdifferentiation between Mast Cell Subpopulations: (mast cells/tissue microenvironment/mutant mice/proteoglycans)

Mast cells are progeny of multipotential hematopoietic stem cells. Although most of the progeny of stem cells leaves the hematopoietic tissue after maturation, undifferentiated precursors of mast cells leave the hematopoietic tissue. Morphologically unidentifiable precursors migrate in the bloodstream, invade the connective tissues or the mucosa of the alimentary canal, proliferate, and then differentiate into mast cells. Even after their morphological differentiation, some mast cells retain an extensive proliferative potential. There are at least two subpopulations of mast cells, a connective-tissue type and mucosal type. Connective tissue-type and mucosal mast cells can be distinguished by histochemical, electron microscopical, biochemical and immunological criteria, but these two types can interchange, and their phenotypes are determined by the anatomical microenvironment in which their final differentiation occurs.