title: RNA and a cell wall component of Enterococcus faecalis IC-1 are required for phagocytosis and interleukin 12 production by the mouse macrophage cell line J774.1.
abstract: Enterococcus faecalis is a resident lactic acid bacterium in the human intestine. Its immunostimulatory action was reported to be enhanced by heat sterilization. To investigate its beneficial actions, we evaluated the ability of 10 E. faecalis strains to induce interleukin-12 (IL-12) production in a mouse macrophage cell line, J774.1 and found that the strain, E. faecalis IC-1, had a potent IL-12-inducing ability. Furthermore, we investigated the underlying mechanism by treating IC-1 cells with RNase or lysozyme. Its activity almost disappeared and an antagonist of Toll-like receptor (TLR) 7 inhibited this activity. Moreover, lysozyme-treated IC-1 bacteria were not phagocytized by J774.1 cells, and did not induce IL-12 production. Based on our results, we propose that macrophages recognize the cell wall components of IC-1, leading to phagocytosis. The IC-1 RNA is then recognized by TLR7, which induces the production of IL-12.
authors.affiliation: a Central Research Institute, ITO EN, Ltd. , Makinohara , Japan.
authors.forename: Junpei
authors.initials: J
authors.lastname: Nakase
authors.affiliation: a Central Research Institute, ITO EN, Ltd. , Makinohara , Japan.
authors.forename: Yuuichi
authors.initials: Y
authors.lastname: Ukawa
authors.affiliation: b Research & Development Division, Chichiyasu Company , Hatsukaichi , Japan.
authors.forename: Syoji
authors.initials: S
authors.lastname: Takemoto
authors.affiliation: b Research & Development Division, Chichiyasu Company , Hatsukaichi , Japan.
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Kubo
authors.affiliation: a Central Research Institute, ITO EN, Ltd. , Makinohara , Japan.
authors.forename: Yuko M
authors.initials: YM
authors.lastname: Sagesaka
authors.affiliation: c Department of Applied Biological Chemistry , The University of Tokyo , Tokyo , Japan.
authors.forename: Ayako
authors.initials: A
authors.lastname: Aoki-Yoshida
authors.affiliation: c Department of Applied Biological Chemistry , The University of Tokyo , Tokyo , Japan.
authors.forename: Mamoru
authors.initials: M
authors.lastname: Totsuka
mesh_terms: D000818:Animals; D002460:Cell Line; D002473:Cell Wall / Q000737:chemistry / Q000187:drug effects / Q000276:immunology*; D018920:Coculture Techniques; D013293:Enterococcus faecalis / Q000737:chemistry / Q000187:drug effects / Q000276:immunology*; D015870:Gene Expression; D018664:Interleukin-12 / Q000096:biosynthesis / Q000276:immunology*; D008264:Macrophages / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000276:immunology; D051379:Mice; D009113:Muramidase / Q000737:chemistry / Q000494:pharmacology; D009841:Oligonucleotides / Q000494:pharmacology; D010587:Phagocytosis / Q000187:drug effects; D012329:RNA, Bacterial / Q000737:chemistry / Q000276:immunology*; D012260:Ribonucleases / Q000737:chemistry / Q000494:pharmacology; D051199:Toll-Like Receptor 7 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000276:immunology
chemical_list: D008562:Membrane Glycoproteins; D009841:Oligonucleotides; D012329:RNA, Bacterial; C477038:Tlr7 protein, mouse; D051199:Toll-Like Receptor 7; D018664:Interleukin-12; D012260:Ribonucleases; D009113:Muramidase
keywords: Enterococcus faecalis; RNA; cell wall component; interleukin 12