Immunologic “colitis” in dogs

Dog colon mucosal extracts are antigenic to rabbits. After several months of an immunization program with adjuvant, antibodies are demonstrable by gel diffusion and increased precipitin titers. When this anti-dog-colon-rabbit serum is given intravenously to recipient dogs, an acute immunologic reaction develops, primarily limited to the colon, but with evidence of systemic participation. In 24 hours this is characterized by mucosal hemorrhage and focal necrosis, leukocytic infiltration most marked at the base of crypts, submucosal edema, venous dilatation, and perivascular cuffing. This reaction requires further investigation for understanding of its mechanism and significance.