title: A novel strain of Bacteroides fragilis enhances phagocytosis and polarises M1 macrophages.
abstract: Commensal Bacteroides fragilis possesses immune-regulatory characteristics. Consequently, it has been proposed as a potential novel probiotic because of its therapeutic effects on immune imbalance, mental disorders and inflammatory diseases. Macrophages play a central role in the immune response, developing either a classical-M1 or an alternative-M2 phenotype after stimulation with various signals. The interactions between macrophages and B. fragilis, however, remain to be defined. Here, a new isolate of B. fragilis, ZY-312, was shown to possess admirable properties, including tolerance to simulated gastric fluid, intestinal fluid and ox bile, and good safety (MOI = 100, 200) and adherent ability (MOI = 100) to LoVo cells. Isolate ZY-312 cell lysate promoted phagocytosis of fluorescent microspheres and pathogenic bacteria in bone marrow-derived macrophage (BMDM) cells. Gene expression of IL-12, iNOS and IL-1β in BMDM cells was increased after treatment with ZY-312, indicating the induction of M1 macrophages, consistent with enhanced secretion of NO. Cell surface expression of CD80 and CD86 was also increased. This study is the first to demonstrate that B. fragilis enhances the phagocytic functions of macrophages, polarising them to an M1 phenotype. Our findings provide insight into the close relationship between B. fragilis and the innate immune system.
authors.affiliation: Guangdong Provincial Key Laboratory of Gastroenterology, Inst. of Gastroenterology of Guangdong Province, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.|State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, No. 20 Dongdajie, Fengtai District, Beijing 100071, China.
authors.forename: Huimin
authors.initials: H
authors.lastname: Deng
authors.affiliation: Guangdong Provincial Key Laboratory of Gastroenterology, Inst. of Gastroenterology of Guangdong Province, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.|State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, No. 20 Dongdajie, Fengtai District, Beijing 100071, China.
authors.forename: Zhengchao
authors.initials: Z
authors.lastname: Li
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, No. 20 Dongdajie, Fengtai District, Beijing 100071, China.
authors.forename: Yafang
authors.initials: Y
authors.lastname: Tan
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, No. 20 Dongdajie, Fengtai District, Beijing 100071, China.
authors.forename: Zhaobiao
authors.initials: Z
authors.lastname: Guo
authors.affiliation: Guangzhou ZhiYi biotechnology Co. Ltd. No. 3, Lanyue Road, International Business Incubator Building F, Guangzhou 510515, China.
authors.forename: Yangyang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Guangzhou ZhiYi biotechnology Co. Ltd. No. 3, Lanyue Road, International Business Incubator Building F, Guangzhou 510515, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, No. 20 Dongdajie, Fengtai District, Beijing 100071, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Yuan
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, No. 20 Dongdajie, Fengtai District, Beijing 100071, China.
authors.forename: Ruifu
authors.initials: R
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, No. 20 Dongdajie, Fengtai District, Beijing 100071, China.
authors.forename: Yujing
authors.initials: Y
authors.lastname: Bi
authors.affiliation: Guangdong Provincial Key Laboratory of Gastroenterology, Inst. of Gastroenterology of Guangdong Province, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Bai
authors.affiliation: Guangdong Provincial Key Laboratory of Gastroenterology, Inst. of Gastroenterology of Guangdong Province, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.
authors.forename: Fachao
authors.initials: F
authors.lastname: Zhi
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion; D001441:Bacteroides fragilis / Q000302:isolation & purification* / Q000502:physiology*; D002460:Cell Line; D016764:Cell Polarity; D006801:Humans; D007113:Immunity, Innate; D018664:Interleukin-12 / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism; D008264:Macrophages / Q000166:cytology* / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D010587:Phagocytosis
chemical_list: D053583:Interleukin-1beta; D018664:Interleukin-12; D052247:Nitric Oxide Synthase Type II