Modulation of FcεRI-dependent mast cell response by OX40L via Fyn, PI3K, and RhoA

The engagement of OX40L selectively suppresses Fyn-initiated signals required for MC degranulation and serves to limit immediate hypersensitivity. Our data suggest that soluble OX40 can restore the aberrant or absent regulatory T-cell activity, revealing a previously unappreciated homeostatic role for OX40L in setting the basal threshold of MC response.