TISSUE-REGULATED DIFFERENTIATION AND MATURATION OF A V-ABL-IMMORTALIZED MAST CELL-COMMITTED PROGENITOR

An immature v-abl-transformed mast cell line (VS-MG) was derived from a mouse that developed systemic mastocytosis after transplantation of v-abl-infected bone marrow cells. V3-MCs injected intravenously into a dult BALB/c mice infiltrated the liver, spleen, and intestine by day 6 and underwent progressive differentiation and maturation, eventually resembling indigenous mast cells. in terms of their protease content, the V3-MCs that localized in the liver and spleen differed from those in the intestine, and both differed from the cultured V3-MCs. The acqu ired expression of certain proteases and the loss of expression of oth er proteases in these tissue V3-MCs defines particular phenotypes and indicates that the differentiation and maturation of mast cell-committ ed progenitor cells are primarily regulated by factors in the differen t tissue microenvironments.