“EFFECT OF LACTIC ACID BACTERIA ON THE IMMUNE SYSTEM”

PERDIGÓN GABRIELA; MALDONADO GALDEANO MARÍA CAROLINA; VINDEROLA GABRIEL; MEDICI MARTA

NUTRITION

Elsevier

Año: 2003 vol. 19 p. 1037 - 1037

0899-9007

The knowledge about the relationship between non-pathogenic bacteria (probiotics) and the host and their influences in the activation of the intestinal mucosal immune system (IMIS) are not well understood yet. Aims: To study the mechanisms involved in the immunomodulation by probiotics in BALB/c mice. Methodology:  L. casei, L. acidophilus and L. delbrueckii subsp. bulgaricus (L.b) were used. We analyzed: 1) Adhesion, internalization and permanence in the gut, by using immunofluorescence (IF) technique and transmission electronic microscopy. 2) The activation/suppression of the immune system by the enumeration of the number of IgA+, TNFa+, IL-2+, IL-10+ and IL-4+ cells and the expression of the protein Bcl-2 by IF on intestinal histological slices after feeding with the optimal doses of the LAB studied. 3) Effect of viability and host specificity in the immunomodulation of the IMIS (IgA+ cells and cytokines) after the administration of viable or heat-dead LAB. 4) Homologous bacteria (L fermentum and B. animalis) were isolated from mice for a comparative study of the immune parameters mentioned above. Results and Conclusion: 1) The interaction of the bacterial antigen is important to active the MIS. The kinetic of antigenic depuration was similar to one observed for a particulate antigen (72 h). The antigenic contact with the immune cells induced an increase in the number of IgA+ cells and the production of proinflammatory and regulatory cytokines. 3) The viability of probiotics warrants a good activation of the IMIS. 4) No relationship between the host specificity and the IMIS stimulation was observed. The immunomodulating properties of LAB were characteristics of each strain and they can not be extrapolated to the bacterial genera or species.