MOUSE MAST-CELLS THAT POSSESS SEGMENTED MULTI-LOBULAR NUCLEI/

Because in humans mast cells and basophils tend to possess nonsegmente d and segmented/multi-lobular nuclei, respectively, nuclear morphology has been a major criterion for assessing the lineage of metachromatic cells of hematopoietic origin. Immature metachromatic cells with mono - and multi-lobular nuclei were both obtained when bone marrow cells f rom BALB/c mice were cultured for 3 weeks in the presence of interleuk in-3. Analogous to the indigenous mature mast cells that reside in the peritoneal cavity and skin, both populations of in vitro-derived cell s expressed the surface receptor c-kit, the chymase mouse mast cell pr otease (mMCP) 5, the tryptase mMCP-6, and the exopeptidase carboxypept idase A (mMC-CPA). Immunogold electron microscopy confirmed the granul e location of mMC-CPA and mMCP-6 in both populations of cells, and cyt ochemical analysis confirmed the presence of chymotryptic enzymes in t he granules. Because mature mast cells possessing multi-lobular nuclei also were occasionally found in the skeletal muscle and jejunum of th e BALB/c mouse, the V3 mouse mast cell line was used to investigate th e developmental relationship of mast cells that have very different nu clear structures, After the adoptive transfer of V3 mast cells into BA LB/c mice, v-abl-immortalized mast cells with mono- and multilobular n uclei were detected in the lymph nodes and other tissues of the mastoc ytosis mice that expressed c-kit, mMCP-5, mMCP-6, and mMC-CPA. These s tudies indicate that mouse mast cells can exhibit varied nuclear profi les. Moreover, the nuclear morphology of this cell type gives no insig ht as to its protease phenotype or stage of development. (C) 1997 by T he American Society of Hematology.