STXBP1 deficiency has no effect on Passive Cutaneous Anaphylaxis (PCA) reactions and late-phase cutaneous anaphylaxis in vivo.

Mast cell-deficient W^sh/W^sh mice were reconstituted locally in the ears and footpads by intradermal injection of wild-type (left ear and left footpad) and STXBP1^−/− (right ear and right footpad) mast cells. A, Mast Cell-reconstituted W^sh mice or W^sh mice (background) were sensitized by intradermal injection of anti-DNP IgE into ears. After 24 hours, mice were challenged by intravenous injection of antigen (DNP-HSA) in 0.5% Evan’s blue. After 30 minutes, Evan’s blue was extracted and the intensity of the dye was measured by absorption at 620 nm. Data are mean ± SEM, n = 6. B, Mast cell-reconstituted W^sh mice were sensitized by intravenous injection of anti-DNP IgE. Twenty-four hours later, a cutaneous reaction was elicited by the application of 20 µl of a solution of 0.3% (weight/volume) dinitrofluorobenzene (DNFB) in acetone/olive oil (4∶1) to the ears and footpads. After another 24 hours, the cutaneous reaction was assessed by comparing the footpad or ear thickness before and after DNFB stimulation according to measurements with a micrometer. Data are mean ± SEM, n = 6.