Basic Research
Copyright ©2008 The WJG Press and Baishideng. All rights reserved.
World J Gastroenterol. Sep 28, 2008; 14(36): 5570-5583
Published online Sep 28, 2008. doi: 10.3748/wjg.14.5570
Potentially probiotic bacteria induce efficient maturation but differential cytokine production in human monocyte-derived dendritic cells
Sinikka Latvala, Taija E Pietilä, Ville Veckman, Riina A Kekkonen, Soile Tynkkynen, Riitta Korpela, Ilkka Julkunen
Sinikka Latvala, Taija E Pietilä, Ville Veckman, Ilkka Julkunen, Department of Viral Diseases and Immunology, National Public Health Institute, Mannerheimintie 166, Helsinki 00300, Finland
Riina A Kekkonen, Riitta Korpela, Pharmacology, Institute of Biomedicine, University of Helsinki, PO Box 63, Helsinki 00014, Finland
Riina A Kekkonen, Soile Tynkkynen, Riitta Korpela, Research Center, Valio Ltd, Meijeritie 4, Helsinki 00370, Finland
Author contributions: Latvala S, Pietilä TE, Veckman V, Kekkonen RA, Tynkkynen S, Korpela R, and Julkunen I designed research and took part in data analysis and paper writing; Latvala S, Pietilä TE, and Kekkonen RA performed the experiments and carried out data analysis; Latvala S, Julkunen I wrote the paper.
Supported by The Medical Research Council of the Academy of Finland and the Sigrid Juselius Foundation
Correspondence to: Sinikka Latvala, Department of Viral Diseases and Immunology, National Public Health Institute, Mannerheimintie 166, Helsinki FIN-00300, Finland. sinikka.latvala@ktl.fi
Telephone: +358-9-47448943 Fax: +358-9-47448355
Received: April 23, 2008
Revised: August 29, 2008
Accepted: September 5, 2008
Published online: September 28, 2008
Abstract

AIM: 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-α, IL-12, IL-6, and CCL20) and Th1 type (IL-12 and IFN-γ) 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-κB) signaling pathways were shown to be involved in bacteria-induced cytokine production.

CONCLUSION: 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.

Keywords: Probiotic bacteria; Immune response; Cytokine; Chemokine; Dendritic cell; Human; Gene expression; Signal transduction