Induction of autoimmune colitis by Yersinia enterocolitica 60-kilodalton heat-shock protein

Background: Many investigations of the relationship between ulcerative coli tis (UC) and heat-shock protein (Hsp) 60 have been reported. We have alread y established an animal model exhibiting UC-lilie lesions caused by adminis tration of Escherichia coli expressing Yersinia enterocolitica Hsp60. In th is study, we therefore attempted to induce mouse colitis by purified Y. ent erocolitica Hsp60. Methods: Purified Y. enterocolitica Hsp60 was injected i ntraperitoneally into B10A/SgSn mice at a dose of 3 mug/0.2 ml once a week for 2 months, and morphological changes in the intestine were examined by L ight and electron microscopical analysis. Autoimmune responses were also ex amined. Results: The mice treated with Y. enterocolitica Hsp60 exhibited im mune reaction between large intestine and autologous serum. Light and elect ron microscopically, degradation of glandular ducts, erosions, ulceration, crypt abscess-like formation, infiltration of inflammatory cells and absenc e of perivascular reticular fibers in lamina propria mucosae and subepithel ial reticular layer were observed. Conclusions: These findings indicate tha t administration of Y. enterocolitica Hsp60 induces UC-like lesions with au toimmune responses.