SYMPOSIUM - PROBIOTIC BACTERIA FOR HUMANS - CLINICAL-SYSTEMS FOR EVALUATION OF EFFECTIVENESS - IMMUNE-SYSTEM STIMULATION BY PROBIOTICS

The immune system consists of organs and several cell types. Antigen i nteraction with these cells induces a cellular immune response mediate d by activated cells and a humoral immune response mediated by antibod ies. The cellular interactions are enhanced by adhesion molecules, and the activated cells release different cytokines. These complex cellul ar interactions induce a systemic immune response. If the antigen pene trates by the oral route, a secretory immune response is obtained, whi ch is mediated by secretory IgA. The determination of the number of T or B cells, the quantitative or qualitative measure of the cytokines, antibody levels, or the study of cellular function such as phagocytic activity is used to evaluate the state of the immune system. The effec ts of lactic acid bacteria on the systemic immune response and on the secretory immune system are described. Potential health benefits of la ctic acid bacteria include protection against enteric infections, use as an oral adjuvant, the immunopotentiator in malnutrition, and the pr evention of chemically induced tumors. The results showed that Lactoba cillus casei could prevent enteric infections and stimulate secretory IgA in malnourished animals, but could produce bacteria translocation. Yogurt could inhibit the growth of intestinal carcinoma through incre ased activity of IgA, T cells, and macrophages.