Only TNF^+/+ mast cells reconstitute PMN recruitment in Kit^W/Kit^W-v ears. MPO activity in protein extracts of ear tissue from Kit^W/Kit^W-v mice reconstituted with either TNF^−/− () or TNF^+/+ (■) mast cells. Ear tissue was harvested 24 hours after TNCB challenge from sensitized and naive Kit^W/Kit^W-v mice (n = 2).