ACTIVATION-SECRETION COUPLING IN 10P2 MURINE MAST-CELLS CHALLENGED WITH IGE-ANTIGEN, IONOPHORE A23187, THAPSIGARGIN AND PHORBOL ESTER

Mast cell activation-secretion by several signal transduction pathways results in the release of proinflammatory mediators including histami ne, proteases, arachidonic acid metabolites and multifunctional cytoki nes. In the present investigations the activation-secretion responses of the cytokine-independent, cloned 10P2 cell line have been explored. [C-14]Serotonin (5-HT) preloaded cells were stimulated with antigen, with and without IL-4, ionophore A23187, thapsigargin or phorbol myris tate acetate (PMA). Following passive sensitization with anti-dinitrop henol (anti-DNP) IgE, mast cells released up to 31% of incorporated [C -14]5-HT when stimulated with specific antigen (DNP-human serum albumi n). This response was potentiated by pretreatment with IL-4. Significa nt degranulation (50%) was noted following treatment with calcium iono phore A23187, thapsigargin and ionophore A23187/PMA. Collectively, the se results suggest that 10P2 cells undergo activation-secretion respon ses, assessed as degranulation of preloaded [C-14]5-HT when challenged with IgE antigen, by influx of extracellular calcium or release of in tracellular calcium stores, or by direct activation of protein kinase isozymes. As a growth factor-independent cell line, 10P2 cells may be a valuable adjunct to existing mast cell model systems currently used for pharmacologic investigations.