ACTIVATED MAST-CELLS RELEASE BIOLOGICAL-ACTIVITIES ABLE TO SUPPORT EOSINOPHIL PRODUCTION FROM MOUSE HEMATOPOIETIC PRECURSORS

Mouse bone marrow cells cultured for 6 days in the presence of recombi nant murine IL-3 and granulocyte-macrophage colony-stimulating factor (GM-CSF) were used as a source of precursors responsive to eosinopoiet ins. They were further cultured for 7 days in the presence of either a combination of recombinant cytokines or supernatants of bone marrow-d erived mast cells (BMMC) activated with either immunological or nonimm unological stimuli. Cytosmears of collected cells were analyzed for eo sinophil contents and allowed to demonstrate that supernatants of pass ively sensitized BMMC support both total cell proliferation and eosino phil production, after various periods of incubation with monoclonal r at anti-mouse IgE antibodies (the 6HD5 mAbs). In contrast, a stimulati on with 100 ng/ml dinitrophenylated bovine serum albumin (DNP-BSA) did not generate supernatants displaying such bioactivities. Low doses of methyl ester of L (but not D)-leucine or of the calcium ionophore A23 187 also allowed the release of eosinopoietic bioactivities. In additi on, immunoreactive IL-5, GM-CSF, and IL-3 were quantified in the BMMC supernatants. These results demonstrate that activated BMMC are able t o effect eosinophil production. (C) 1996 Academic Press, Inc.