Experimental colitis in rabbits.

Experimental colitis was induced in rabbits either by immunizing the antigens which possess the cross-reacting antigenicity with colonic mucosa, and by infusing intravenously their own lymphocytes sensitized with E. coli 014 endotoxin which may contain a high concentration of common antigen (Kunin antigen). The hemorrhagic inflammatory changes were developed in the colon as follows; (1) three of fifteen rabbits immunized with rat colon, (2) one of three rabbits with their own E. coli, (3) six of fifteen rabbits with E. coli 014 and, (4) five of eight rabbits by infusing their own lymphocytes sensitized with E. coli 014 endotoxin. It was suggested that the cross-reacting antigenicity with the colonic mucosa and the sensitized lymphocytes implicate in the pathogenesis of chronic ulcerative colitis.