Delayed hypersensitivity reactions in the intestinal tract

Nineteen niniature swine were skin-sensitized to 2–4 dinitrochlorobenzene (DNCB) and had a colostomy in the midtransverse colon. All were given DNCB in adhesive paste 3 times weekly for 6 months, through the colostomy. In addition 6 animals received Freund's complete adjuvant, 6 were given E. coli endotoxin, and 4 were given neostigmine 2 times weekly for 6 months. The morphological changes produced in all animals were those of microscopic ulceration and partial glandular destruction. The lamina propria showed a chronic inflammatory infiltrate. The vessels showed perivascular congestion. The adjuvant group seemed to have a more grossly intense lesion. In the neostigmine group, crypt abscesses were found in all pigs, the first production of such lesions in an experimental model.