Induction of granulomas in mice by Crohn's disease tissue.

Normal and immunodeficient CBA and A2G strain mice were inoculated with crude (100 to 20 to 30 micrometer), cell-free (0.2 micrometer) filtrates of Crohn's or noninflammatory bowel disease tissue homogenates, which were either fresh or frozen to -70 degree C. Mice of each strain developed epithelioid and giant cell granulomas both locally at the site of injection and systemically in response to crude and cell-free filtrates of Crohn's tissues. Control mice did not develop such changes. The granulomas evolved slowly, predominantly between 9 and 27 months. The granuloma-inciting agent has been shown to be present in ileum, colon, and mesenteric lymph nodes of patients with Crohn's disease and it withstands freezing to -70 degree C. The use of Crohn's tissues common to this study and one in rabbits previously reported, suggests that the induction of granulomas by this agent is not strain- or species-specific, and is independent of the immune status of CBA mice.