Potentially probiotic bacteria induce efficient maturation but differential cytokine production in human monocyte-derived dendritic cells.
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.
Latvala
Sinikka
S
Department of Viral Diseases and Immunology, National Public Health Institute, Mannerheimintie 166, Helsinki Finland. sinikka.latvala@ktl.fi
Pietila
Taija-E
TE
Veckman
Ville
V
Kekkonen
Riina-A
RA
Tynkkynen
Soile
S
Korpela
Riitta
R
Julkunen
Ilkka
I
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
D018925:Chemokines; D016207:Cytokines; D012333:RNA, Messenger