Stimulation of macrophages by immunobiotics: influence beyond the intestinal tract

JULIO VILLENA; SUSANA SALVA; GABRIELA MARRANZINO; SUSANA ALVAREZ

Sendai

Congreso; Reunion Anual de la Sociedad Japonesa de Bacterias Lacticas; 2010

Lactobacillus rhamnosus CRL 1505 (Lr05), L. rhamnosus CRL 1506 (Lr06) and L. casei CRL 431 (Lc) are able to stimulate intestinal immunity, but only Lr05 and Lc are able to stimulate immunity in the respiratory tract (1,2). With the aim of advancing in the understanding of the immunological mechanisms involved in the stimulation of distant mucosal sites, this study evaluated the effect of orally administered immunobiotics on alveolar (Mfa) and peritoneal (Mfp) macrophages function. Swiss mice (6-week) were fed Lc05 or Lc06 for 5 consecutive days or Lc for 2 days. At the end of each treatment we evaluated: a) Mfa and Mfp microbicidal activity against Candida albicans (Ca) b) IFNγ and TNFα levels after stimulation with LPS; c) NBT+ cells in peritoneal and alveolar fluids, d) Ca clearance after an intraperitoneal (107 cells) or intranasal (108 cells) challenges; e) number and activity of blood and respiratory leucocytes, IFNγ and TNFα levels after the Ca challenges. The three strains were able to significantly increase phagocytic and microbicidal activities of Mfp compared with the control group (C). After the intraperitoneal challenge, mice treated with immunobiotics showed significantly lower Ca counts in liver and spleen than C and an improved immune response. Only Lc05 and Lc were able to improve activity and cytokines production by Mfa. Moreover, only these two groups showed significantly lower lung Ca counts and an improved respiratory immune response when compared with the C group. These and previous findings allow us to propose the following mechanism: immunobiotics would be able to induce the stimulation of the Th1 response in the gut. Some immunobiotics strains would be able to induce mobilization of Th1 cells from inductive sites in the gut to effector sites in the respiratory tract, Mobilized Th1 cells would produce cytokines that stimulate the activity of local respiratory immune cells such as alveolar macrophages (1, 2, 3). (1) Salva et al., 2010, Int. J. Food Microbiol. In press. (2) Alvarez et al., 2009, Curr. Res. Immunol. 3:87-126. (3) Villena et al., 2008, Can. J. Microbiol. 54:630-38.