in mice: the effects of terreic acid (TA) (0.15; 1.5; 15 mg/kg) on IgE/antigen-mediated cutaneous reactions in BALB/c were examined. Mice received i.v. injection of antidinitrophenyl IgE antibody followed by epicutaneous administration of 0.15% dinitrofluorobenzene 24 hr later. TA was injected i.p. 1 hr before antigen challenge. The increased ear thickness resulting from an edematous allergic reaction occurs from 2 hr after antigen challenge and continues for at least 48 hr. The early response, as examined 1 hr after antigen challenge, was not affected by TA.

In vitro binding assays were perfomed using GST-BtkPH beads and HMC-1 cell lysates. GST-BtkPH beads were incubated with HMC-1 cell lysates in the absence or presence of various concentrations of terreic acid (0, 50, 100, 300 uM). PKC in HMC-1 lysates, which bound to the Btk PH domain beads, was detected by immunoblotting with anti-PKC (MC5). It was shown, that terreic acid inhibited the binding of GST-BtkPH to PKC in lysates of HMC-1 human mast cells with an IC50 of ≈100 μM