title: Bifidobacterium infantis attenuates colitis by regulating T cell subset responses.
abstract: OBJECTIVE
  to investigate the effect of Bifidobacterium infantis (B. infantis) on the T cell subsets and in attenuating the severity of experimental colitis in mice.
  
  
  METHODS
  Normal BALB/c mice were fed different doses of B. infantis for 3 wk, and T cell subsets and related cytokine profiles in mesenteric lymph nodes (MLNs) were detected by flow cytometry and real-time RT-PCR. Colitis was induced by administration of trinitrobenzene sulfonic acid (TNBS) in mice. Before colitis induction, mice were fed high dose B. infantis for 3 wk. Cytokine profiles in MLNs and histological changes of colonic tissue were examined 6 d after colitis induction.
  
  
  RESULTS
  No significant change in cytokine profiles was observed in normal mice fed low dose B. infantis. However, Th1-related cytokines (IL-2, IFN-γ, IL-12p40), Th17-related transcription factor and cytokines (RORγt, IL-21, IL-23), regulatory T cell (Treg)-related transcription factor and cytokines (Foxp3, IL-10) were increased in normal mice fed high dose B. infantis. Furthermore, flow cytometry assay showed B. infantis increased the numbers of CD4(+)Foxp3(+) Tregs and Th17 cells in MLNs. Colitis was successfully induced by TNBS in mice, characterized by colonic inflammation and aberrant Th1 and Th17 responses. Feeding high dose B. infantis for 3 wk before colitis induction decreased the inflammatory cell infiltration and goblet cell depletion and restored the intestinal epithelium. In addition, B. infantis feeding reduced Th1-related cytokines (T-bet, IL-2 and IFN-γ) and Th17-related cytokines (IL-12p40, RORγt, IL-17A, IL-21 and IL-23), and increased Treg-related molecules (Foxp3, IL-10 and TGF-β) in colitis mice.
  
  
  CONCLUSIONS
  B. infantis effectively attenuates TNBS-induced colitis by decreasing Th1 and Th17 responses and increasing Foxp3(+) Treg response in the colonic mucosa.
authors.affiliation: Li Zuo, Qing-Hong Meng, Peter Chee-Keung Chung, Department of Immunology, Guiyang Medical College, Guiyang 550004, Guizhou Province, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zuo
authors.affiliation: Li Zuo, Qing-Hong Meng, Peter Chee-Keung Chung, Department of Immunology, Guiyang Medical College, Guiyang 550004, Guizhou Province, China.
authors.forename: Kai-Tao
authors.initials: KT
authors.lastname: Yuan
authors.affiliation: Li Zuo, Qing-Hong Meng, Peter Chee-Keung Chung, Department of Immunology, Guiyang Medical College, Guiyang 550004, Guizhou Province, China.
authors.forename: Li
authors.initials: L
authors.lastname: Yu
authors.affiliation: Li Zuo, Qing-Hong Meng, Peter Chee-Keung Chung, Department of Immunology, Guiyang Medical College, Guiyang 550004, Guizhou Province, China.
authors.forename: Qing-Hong
authors.initials: QH
authors.lastname: Meng
authors.affiliation: Li Zuo, Qing-Hong Meng, Peter Chee-Keung Chung, Department of Immunology, Guiyang Medical College, Guiyang 550004, Guizhou Province, China.
authors.forename: Peter Chee-Keung
authors.initials: PC
authors.lastname: Chung
authors.affiliation: Li Zuo, Qing-Hong Meng, Peter Chee-Keung Chung, Department of Immunology, Guiyang Medical College, Guiyang 550004, Guizhou Province, China.
authors.forename: Ding-Hua
authors.initials: DH
authors.lastname: Yang
mesh_terms: D000818:Animals; D001644:Bifidobacterium / Q000145:classification / Q000276:immunology*; D003092:Colitis / Q000139:chemically induced / Q000276:immunology / Q000378:metabolism / Q000382:microbiology / Q000473:pathology / Q000628:therapy*; D003106:Colon / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology* / Q000473:pathology; D016207:Cytokines / Q000276:immunology / Q000378:metabolism; D004195:Disease Models, Animal; D005260:Female; D008807:Mice, Inbred BALB C; D019936:Probiotics; D012720:Severity of Illness Index; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000382:microbiology; D018417:Th1 Cells / Q000276:immunology / Q000382:microbiology; D058504:Th17 Cells / Q000276:immunology / Q000382:microbiology; D013997:Time Factors; D014302:Trinitrobenzenesulfonic Acid
chemical_list: D016207:Cytokines; D014302:Trinitrobenzenesulfonic Acid
keywords: Bifidobacterium; Colitis; Cytokines; Regulatory T cells; Th17