title: Microbial recognition via Toll-like receptor-dependent and -independent pathways determines the cytokine response of murine dendritic cell subsets to CD40 triggering.
abstract: Dendritic cells (DC) can produce Th-polarizing cytokines and direct the class of the adaptive immune response. Microbial stimuli, cytokines, chemokines, and T cell-derived signals all have been shown to trigger cytokine synthesis by DC, but it remains unclear whether these signals are functionally equivalent and whether they determine the nature of the cytokine produced or simply initiate a preprogrammed pattern of cytokine production, which may be DC subtype specific. Here, we demonstrate that microbial and T cell-derived stimuli can synergize to induce production of high levels of IL-12 p70 or IL-10 by individual murine DC subsets but that the choice of cytokine is dictated by the microbial pattern recognition receptor engaged. We show that bacterial components such as CpG-containing DNA or extracts from Mycobacterium tuberculosis predispose CD8alpha(+) and CD8alpha(-)CD4(-) DC to make IL-12 p70. In contrast, exposure of CD8alpha(+), CD4(+) and CD8alpha(-)CD4(-) DC to heat-killed yeasts leads to production of IL-10. In both cases, secretion of high levels of cytokine requires a second signal from T cells, which can be replaced by CD40 ligand. Consistent with their differential effects on cytokine production, extracts from M. tuberculosis promote IL-12 production primarily via Toll-like receptor 2 and an MyD88-dependent pathway, whereas heat-killed yeasts activate DC via a Toll-like receptor 2-, MyD88-, and Toll/IL-1R domain containing protein-independent pathway. These results show that T cell feedback amplifies innate signals for cytokine production by DC and suggest that pattern recognition rather than ontogeny determines the production of cytokines by individual DC subsets.
authors.affiliation: Immunobiology Laboratory, Cancer Research U.K., London Research Institute, London, United Kingdom.
authors.forename: Alexander D
authors.initials: AD
authors.lastname: Edwards
authors.forename: Shivanthi P
authors.initials: SP
authors.lastname: Manickasingham
authors.forename: Roman
authors.initials: R
authors.lastname: Spörri
authors.forename: Sandra S
authors.initials: SS
authors.lastname: Diebold
authors.forename: Oliver
authors.initials: O
authors.lastname: Schulz
authors.forename: Alan
authors.initials: A
authors.lastname: Sher
authors.forename: Tsuneyasu
authors.initials: T
authors.lastname: Kaisho
authors.forename: Shizuo
authors.initials: S
authors.lastname: Akira
authors.forename: Caetano
authors.initials: C
authors.lastname: Reis e Sousa
mesh_terms: D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000276:immunology / Q000378:metabolism; D019013:CD40 Antigens / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D002478:Cells, Cultured; D018920:Coculture Techniques; D016207:Cytokines / Q000096:biosynthesis*; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology*; D029721:Drosophila Proteins; D005260:Female; D005656:Fungal Proteins / Q000276:immunology / Q000378:metabolism; D008297:Male; D008562:Membrane Glycoproteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D016513:Mice, SCID; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D015800:Protozoan Proteins / Q000276:immunology / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology*; D051195:Toll-Like Receptor 2; D051193:Toll-Like Receptors
chemical_list: D001426:Bacterial Proteins; D019013:CD40 Antigens; D016207:Cytokines; D029721:Drosophila Proteins; D005656:Fungal Proteins; D008562:Membrane Glycoproteins; D015800:Protozoan Proteins; D011956:Receptors, Cell Surface; D051195:Toll-Like Receptor 2; D051193:Toll-Like Receptors