Spontaneous degranulation of cultured bone-marrow-derived immature mast cells from X-linked immunodeficient (Xid) mice

IgE-mediated, antigen-dependent stimulation of immature mouse mast cells cultured in IL-3-containing media produces secretion by granule exocytosis. Similar cultured mast cells were derived from X-linked immunodeficient (Xid) mice and examined by electron microscopy. In these cultures, Xid mast cells were also immature. In contrast to cultures obtained From control mice, 10-20% of the immature mast cells of Xid origin were undergoing secretion by granule extrusion in the absence of any secretogogue. Spontaneous secretion may be related to discordered tyrosine kinase function and/or signal transduction pathways in the Xid mouse.