CHARACTERIZATION OF DEFECTIVE PHORBOL ESTER RESPONSES IN A LOW SECRETING RAT BASOPHILIC LEUKEMIA (RBL-2H3) CELL VARIANT

The role of protein kinase C (PKC) in the signaling mechanism that sti mulates the release of mediators from rat mast cells, for which the RB L-2H3 cell line is a model, is at present unresolved. Current evidence suggests that PKC activation alone is an insufficient stimulus, altho ugh it can modulate mast cell exocytosis induced by other agents. In t his article we characterize a variant of the RBL-2H3 cell line that ha s a reduced capacity for mediator secretion in response to an IgE-medi ated antigen-induced stimulation. The outcome of our study suggests th at at least two PKC isotypes are active in RBL-2H3 cells, and affect t he positive and negative modulation of the secretory response.