Stimulation of macrophages by immunobiotics: influence beyond the intestinal tract

VILLENA, JULIO; SALVA, SUSANA; MARRANZINO, GABRIELA; KITASAWA, HARUKI; ALVAREZ, SUSANA

Sendai

Encuentro; The 2010 Annual Meeting of the Japan Society of Lactic Acid Bacteria; 2010

Lactobacillus rhamnosus CRL1505 (Lr05), L. rhamnosus CRL1506 (Lr06) and L. casei CRL431 (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. Six-week old Swiss mice 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) blood and respiratory leukocytes number and activity and 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 innate 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 innate respiratory immune response when compared with C. These and previous findings allow us to propose the following mechanism: some immunobiotics would be able to induce the stimulation of the Th1 response in the gut. In addition, immunobiotics would be able to induce movilization of Th1 cells from inductive sites in the gut to effector sites in the respiratory tract, where they would produce cytokines that stimulate the activity local immune cells such as alveolar macrophages