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Role of intestinal bacterial flora in oral tolerance induction K. Tanaka and H. Ishikawa Department of Infectious Diseases, Tokai University School of Medicine, Kanagawa, Japan Offprint requests to: Kazuo Tanaka, M.D., Ph.D., Department of Infectious Diseases, Tokai University School of Medicine, Bohseidai, Isehara, Kanagawa 259-1193, Japan. Fax: 81-463-94-2976. e-mail: tanakaka@is.icc.u-tokai.ac.jp
Summary. In healthy individuals, the immune responses against foods cannot be induced. This phenomenon is known as oral tolerance. We observed that the oral tolerance was impaired in germfree mice, and that Th2-dependent antibodies such as IgE could be thus induced by an orally given antigen. As a result, the germfree mouse was considered to be a good animal model for allergic disorder. When germfree mice were mono-associated with such bacteria as E.coli and B. infantis, then oral tolerance was restored in these gnotobiotes to a level similar to that observed in SPF mice. Thus, these bacterias seemed to be important in oral tolerance induction. In addition, the probiotics using these bacteria may be a useful material for the treatment of allergic disorders. Histol. Histopathol. 19, 907-914 (2004) Key words: Oral
tolerance, Bacterial flora, Th1/Th2 Balance, Food allergy, probiotics |