Abstract
The intestinal immune system is an extremely elaborate biological defense system. It has characteristic immunological organs and cells for protecting against pathogenic bacteria and the suppression of the onset of food allergy.Immunoglobulin A is generated to prevent the invasion of pathogenic bacteria, and oral tolerance is induced to inhibit food allergy. Intestinal bacteria strongly influence the activation and modulation of the intestinal immune system.Moreover, prebiotics contribute to the stimulation of specific bacteria in the large intestine. Raffinose, a typical prebiotic, is found to inhibit the production of immunoglobulin E, which is associated with the onset of allergy.