No abstract

Summary Guinea pigs sensitized epicutaneously to 2,4-dinitro-1-chlorobenzene and shown to exhibit typical delayed-type hypersensitivity on the skin were found to exhibit equivalent reactions, upon proper challenge, also on the epithelium of the vagina, the uterus and the colon. The reactions are defined histologically by emigrated and accumulated small lymphocytes which tend to move toward, and to affect, the epithelial cells directly below the site of the applied chemical. Conversely, sensitizing applications made to the mucosa of the colon resulted in contact sensitivity of the skin. The fact that contact sensitivity was found not to be limited to the skin appears to exclude a role for keratin or prekeratin as required carrier of the hapten.