Oral supplementation of Bifidobacterium longum strain BR-108 alters cecal microbiota by stimulating gut immune system in mice irrespectively of viability.

Effect on cecal microbiota and gene expression of various cytokines in ileal Peyer's patches and cecal tissues were compared between viable and heat-killed Bifidobacterium longum strain BR-108 (BR-108) using a mouse model. Irrespectively of viability, oral supplementation of BR-108 altered the cecal microbiota and stimulated gene expression of cytokines such as IL-6 and IL-10 in ileal Peyer's patches and cecal tissue of mice. In addition, BR-108 supplementation significantly affected the relative abundance of bacterial genera and family, Oscillospira, Bacteroides and S24-7.

RNA of Enterococcus faecalis Strain EC-12 Is a Major Component Inducing Interleukin-12 Production from Human Monocytic Cells.

Interleukin-12 (IL-12) is an important cytokine for the immunomodulatory effects of lactic acid bacteria (LAB). Using murine immune cells, we previously reported that the RNA of Enterococcus faecalis EC-12, a LAB strain exerting probiotic-like beneficial effects, is the major IL-12-inducing immunogenic component. However, it was recently revealed that bacterial RNA can be a ligand for Toll-like receptor (TLR) 13, which is only expressed in mice.

Role of the mannose receptor in phagocytosis of Enterococcus faecalis strain EC-12 by antigen-presenting cells.

The aim of this study was to clarify the phagocytic mechanisms of a heat-killed cell preparation of Enterococcus faecalis strain EC-12 (EC-12) by antigen-presenting cells (APCs). Fluorescein isothiocyanate (FITC)-labeled EC-12 was cocultured with peritoneal macrophage and the amount of EC-12 phagocytosed by peritoneal macrophages was measured using a microplate fluorometer. Peritoneal macrophages from toll-like receptor (TLR)2-, TLR7-, and MyD88-deficient knockout (KO) mice exhibited similar levels of EC-12 phagocytosis to those from wild-type mice.