Hepatitis C Virus Pathogen Associated Molecular Pattern (PAMP) Triggers Production of Lambda-Interferons by Human Plasmacytoid Dendritic Cells
Figure 3
pDC-GEN2.2 cells sense HCV PAMP and produce Type I and Type III IFNs.
A) Cartoon of the 3′ end of the HCV genome indicating the location of the poly U/UC (pU/UC, HCV PAMP) and the X-region in the 3′ UTR. Adapted from reference [20]. B) Kinetics of interferon gene upregulation in GEN2.2 cells following transfection with the pU/UC RNA. Fold increases for each gene at each condition are shown after normalization to reference gene GAPDH and are compared to transfection with the X-region RNA (dashed line). Levels of IFN expression at 2 (white bars), 4 (gray bars), 8 (hashed bars) or 24 (black bars) hours are shown for each gene. C) Kinetics of PRR genes and ISGs show upregulation by pU/UC stimulation. Kinetics are shown as indicated in A for the IFN genes. D–G) Secretion of Type I and III IFNs by pDC-GEN2.2 cells following PAMP-stimulation. Increased production of D) IFNα, E) IFNβ, F) IL-28A/IFNλ2 and G) IL-29/IFNλ1 as detected by ELISA from pDC-GEN2.2 cells that have been stimulated with HCV PAMP compared to the X-region RNA. H) Western Blot of pDC-GEN2.2 cell lysates for IL-28B/IFNλ3 after 24 hours of HCV PAMP stimulation. The antibody was specific for IL-28B/IFNλ3 as it recognized low levels of recombinant IL-28B/IFNλ3 (rIL-28B; 10 ng) but failed to recognize recombinant IL-28A/IFNλ2 (rIL-28A; 5 µg). I) pU/UC-stimulation increases PRR signaling proteins in accordance to gene expression data. Western blots of listed PRR proteins after 8 or 24 hours stimulation with HCV PAMP RNA. B–C) Combined data from 5 independent experiments. D–I) Combined data from 3 independent experiments except for the gene expression graphs which are 5 independent experiments. H–I) Representative blots from 3 independent experiments. Densitometry shows relative density of each band after normalization to the reference protein. For gene expression graphs, p values are the Wilcoxon signed rank result for each gene and time point compared to the X-region stimulation from the same gene and time point. For ELISA and Densitometry graphs, p values are the Mann-Whitney result for the pU/UC condition compared to the X-region condition. * p<0.05 ** p<0.01 *** p<0.001 # p≤0.0001 Bars represent the mean and error bars are +/− SEM.