Effect of multiple activation stimuli on the generation of Th1-polarizing dendritic cells.
It was originally reported that only a small fraction of total matured dendritic cells (DCs) produced interleukin (IL)-12, but it has never been determined whether different combinations of activating signals now shown to maximize secreted IL-12 do so through increasing output by the same IL-12 producers, or by recruiting additional cytokine-secreting cells. We therefore tested all combinations of bacterial lipopolysaccharide (LPS) (TLR4 ligand), R848 (TLR8 ligand), interferon (IFN)-γ, and CD40L for activating human monocyte-derived dendritic cells (DC), and determined by intracellular flow cytometry that enhanced IL-12 secretion was accomplished in large part by markedly increasing the proportion of cells producing IL-12, with the triple and quadruple combinations recruiting the most DC. This optimization requirement for multiple signals was not reflected in differential Toll-like receptor (TLR) expression by the cells. Interestingly, DCs activated with single TLR ligands plus IFN-γ were capable of responding with a second burst of IL-12 upon later CD40L stimulation, whereas DCs activated with R848 plus LPS were not, despite the trend of the latter for superior polarization of naive T cells toward IFN-γ-secreting Th1. These results have implications for the biology of IL-12-secreting DCs and choice of activation regimen for prospective use in DC-based immunotherapy.
Department of Biomedical Sciences, Kent State University, Kent, Ohio, USA.
Christopher
C
Paustian
Richard
R
Caspell
Terrence
T
Johnson
Peter A
PA
Cohen
Suyu
S
Shu
Shuwen
S
Xu
Brian J
BJ
Czerniecki
Gary K
GK
Koski
D000954:Antigens, Surface / Q000276:immunology; D023201:CD40 Ligand / Q000276:immunology / Q000378:metabolism; D016764:Cell Polarity / Q000276:immunology*; D016207:Cytokines / Q000276:immunology / Q000378:metabolism; D003713:Dendritic Cells / Q000166:cytology* / Q000276:immunology*; D006801:Humans; D016898:Interferon-alpha / Q000276:immunology / Q000378:metabolism; D018664:Interleukin-12 / Q000276:immunology / Q000378:metabolism; D008070:Lipopolysaccharides / Q000276:immunology / Q000378:metabolism; D010641:Phenotype; D018417:Th1 Cells / Q000166:cytology* / Q000276:immunology*; D051193:Toll-Like Receptors / Q000276:immunology / Q000378:metabolism
D000954:Antigens, Surface; D016207:Cytokines; D016898:Interferon-alpha; D008070:Lipopolysaccharides; D051193:Toll-Like Receptors; D023201:CD40 Ligand; D018664:Interleukin-12