title: Potentially probiotic bacteria induce efficient maturation but differential cytokine production in human monocyte-derived dendritic cells.
abstract: OBJECTIVE
  To analyze the ability of nine different potentially probiotic bacteria to induce maturation and cytokine production in human monocyte-derived dendritic cells (moDCs).
  
  
  METHODS
  Cytokine production and maturation of moDCs in response to bacterial stimulation was analyzed with enzyme-linked immunosorbent assay (ELISA) and flow cytometric analysis (FACS), respectively. The kinetics of mRNA expression of cytokine genes was determined by Northern blotting. The involvement of different signaling pathways in cytokine gene expression was studied using specific pharmacological signaling inhibitors.
  
  
  RESULTS
  All studied bacteria induced the maturation of moDCs in a dose-dependent manner. More detailed analysis with S. thermophilus THS, B. breve Bb99, and L. lactis subsp. cremoris ARH74 indicated that these bacteria induced the expression of moDC maturation markers HLA class II and CD86 as efficiently as pathogenic bacteria. However, these bacteria differed in their ability to induce moDC cytokine gene expression. S. thermophilus induced the expression of pro-inflammatory (TNF-alpha, IL-12, IL-6, and CCL20) and Th1 type (IL-12 and IFN-gamma) cytokines, while B. breve and L. lactis were also potent inducers of anti-inflammatory IL-10. Mitogen-activated protein kinase (MAPK) p38, phosphatidylinositol 3 (PI3) kinase, and nuclear factor-kappa B (NF-kappaB) signaling pathways were shown to be involved in bacteria-induced cytokine production.
  
  
  CONCLUSIONS
  Our results indicate that potentially probiotic bacteria are able to induce moDC maturation, but their ability to induce cytokine gene expression varies significantly from one bacterial strain to another.
authors.affiliation: Department of Viral Diseases and Immunology, National Public Health Institute, Mannerheimintie 166, Helsinki Finland. sinikka.latvala@ktl.fi
authors.forename: Sinikka
authors.initials: S
authors.lastname: Latvala
authors.forename: Taija-E
authors.initials: TE
authors.lastname: Pietila
authors.forename: Ville
authors.initials: V
authors.lastname: Veckman
authors.forename: Riina-A
authors.initials: RA
authors.lastname: Kekkonen
authors.forename: Soile
authors.initials: S
authors.lastname: Tynkkynen
authors.forename: Riitta
authors.initials: R
authors.lastname: Korpela
authors.forename: Ilkka
authors.initials: I
authors.lastname: Julkunen
mesh_terms: D001644:Bifidobacterium / Q000254:growth & development; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D018925:Chemokines / Q000378:metabolism; D016207:Cytokines / Q000235:genetics / Q000378:metabolism*; D003713:Dendritic Cells / Q000187:drug effects / Q000276:immunology / Q000382:microbiology*; D006094:Gram-Positive Bacteria / Q000254:growth & development*; D006801:Humans; D007700:Kinetics; D013294:Lactococcus lactis / Q000254:growth & development; D019936:Probiotics; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction; D048249:Streptococcus thermophilus / Q000254:growth & development
chemical_list: D018925:Chemokines; D016207:Cytokines; D012333:RNA, Messenger