title: Immunomodulatory effects of lactobacillus and Bifidobacterium on both murine and human mitogen-activated T cells.
abstract: BACKGROUND
  Beneficial effects of probiotics have been reported for patients with allergic diseases and intestinal disorders. There is increasing interest in studying the role of different strains or combined probiotic administration on immunoregulation. In this study, we investigated whether probiotics modulate the immune response through regulating T cell proliferation and differentiation.
  
  
  METHODS
  We examined the effect of probiotic I (a combination of Lactobacillus acidophilus and Bifidobacterium bifidus) and probiotic II (a combination of L. acidophilus and B. infantis) on cell survival and proliferation, the progression of the cell cycle, and the production of Th1/Th2 cytokines by mitogen-stimulated murine spleen cells and human peripheral blood mononuclear cells (PBMCs).
  
  
  RESULTS
  Our experimental results showed that high concentrations (≥ 1 × 10(6) CFU/ml) of probiotic I or II inhibited mitogen-induced cell proliferation and arrested the cell cycle at the G0/G1 stage in both mitogen-stimulated spleen cells and PBMCs. In the results of low concentrations (<1 × 10(6) CFU/ml), probiotic I or II enhanced the production of IFN-γ but inhibited the production of IL-4. Our results indicated that high concentrations of probiotic I or II treatment could attenuate mitogen-induced overactive immune responses. On the other hand, low concentrations of probiotic I or II treatment could promote a shift in the Th1/Th2 balance toward Th1-skewed immunity.
  
  
  CONCLUSIONS
  Dose selection is an important issue for probiotic studies. Our results indicated that probiotics have beneficial effects on regulating T cell-mediated immune responses by attenuating mitogen-induced overactive immune responses and promoting Th1 immune responses.
authors.affiliation: Division of Infectious Diseases, National Health Research Institutes, Miaoli, Taiwan, ROC.
authors.forename: Chia-Yang
authors.initials: CY
authors.lastname: Li
authors.forename: Hung-Chih
authors.initials: HC
authors.lastname: Lin
authors.forename: Chih-Ho
authors.initials: CH
authors.lastname: Lai
authors.forename: John Jenn-Yenn
authors.initials: JJ
authors.lastname: Lu
authors.forename: Shu-Fen
authors.initials: SF
authors.lastname: Wu
authors.forename: Shih-Hua
authors.initials: SH
authors.lastname: Fang
mesh_terms: D000818:Animals; D001644:Bifidobacterium / Q000276:immunology*; D002453:Cell Cycle / Q000276:immunology; D002470:Cell Survival / Q000276:immunology; D005434:Flow Cytometry; D006801:Humans; D007155:Immunologic Factors / Q000494:pharmacology*; D007371:Interferon-gamma / Q000276:immunology; D015847:Interleukin-4 / Q000276:immunology; D007778:Lactobacillus / Q000276:immunology*; D007963:Leukocytes, Mononuclear; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D019936:Probiotics / Q000494:pharmacology*; D013601:T-Lymphocytes / Q000276:immunology* / Q000382:microbiology*
chemical_list: D007155:Immunologic Factors; D015847:Interleukin-4; D007371:Interferon-gamma