The Src kinase Lyn is a negative regulator of mast cell proliferation

Abstract

Previous investigators have reported that deletion of the protein tyrosine kinase Lyn alters mast cell (MC) signaling responses but does not affect or reduces the cytokine-mediated proliferation of mouse bone marrow-derived MC (BMMC) precursors and of mature MC. We observed that Lyn-deficient mice have more peritoneal MC than wild-type (WT) mice. Studies to explore this unexpected result showed that Lyn-/- BM cells expand faster than WT cells in response to interleukin (IL)-3 and stem-cell factor over the 4-5 weeks required to produce a <95% pure population of granular, receptor with high affinity for immunoglobulin E-positive BMMC. Furthermore, differentiated Lyn -/- BMMC continue to prolif..