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Human type 2 myeloid dendritic cells produce interferon-? and amplify interferon-? in response to hepatitis C virus infection.

ABSTRACT: BACKGROUND & AIMS:The type III interferons (IFN-?s: interleukin [IL]-28a, IL-28b, and IL-29) have important roles in hepatitis C virus (HCV) infection, but little is understood about what cells produce these cytokines or how production is activated. We investigated whether human immune cells recognize HCV-infected cells and respond by producing IFN-?. METHODS:We cultured healthy human peripheral blood mononuclear cells (PBMCs) with different populations of immune cells and Japanese fulminant hepatitis-1 (JFH-1) HCV-infected Huh7.5 (cell culture-derived HCV particles [HCVcc]/Huh7.5) cells. RESULTS:Human PBMCs recognized HCVcc/Huh7.5 cells and responded by producing IFN-?, IFN-?, and IFN-?. A rare subset of myeloid dendritic cells (mDCs), which are blood DC antigen (BDCA)+ (also called mDC2 cells), were the major source of IL-28 and IL-29 production in response to HCVcc/Huh7.5 cells. Plasmacytoid DCs produced IFN-?, whereas natural killer and natural killer T cells were the main source of IFN-? production in co-culture experiments. Of the endosomal Toll-like receptors (TLRs)3, 7, 8, and 9, only TLR3 or double-stranded HCV RNA induced production of IL-28 and IL-29 by mDC2s; endosomal maturation was required. Production of IFN-? and IFN-? were linked-IFN-? increased production of IFN-? by plasmacytoid DCs and IFN-? significantly increased production of IFN-?. CONCLUSIONS:mDC2s are a major source of IFN-? production by PBMCs in response to HCVcc/Huh7.5 cells. mDC2s are activated through the TLR3 pathway, indicating that human DCs efficiently can initiate an immune response against HCV infection. IFN-? therefore has an important role in HCV infection.

SUBMITTER: Zhang S

PROVIDER: S-EPMC3568254 | biostudies-literature | 2013 Feb

REPOSITORIES: biostudies-literature

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Human type 2 myeloid dendritic cells produce interferon-λ and amplify interferon-α in response to hepatitis C virus infection.

Zhang Shuye S Kodys Karen K Li Kui K Szabo Gyongyi G

Gastroenterology 20121023 2

<h4>Background & aims</h4>The type III interferons (IFN-λs: interleukin [IL]-28a, IL-28b, and IL-29) have important roles in hepatitis C virus (HCV) infection, but little is understood about what cells produce these cytokines or how production is activated. We investigated whether human immune cells recognize HCV-infected cells and respond by producing IFN-λ.<h4>Methods</h4>We cultured healthy human peripheral blood mononuclear cells (PBMCs) with different populations of immune cells and Japanes ...[more]

PMID: 23089201

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Project description:BACKGROUND:Cytokines are proteins that mediate innate and adaptive immunity responses. It is hypothesized that interferon lambda 3 (IFNL3) levels can influence the outcome of chronic hepatitis B virus (HBV) infection. Polymorphisms in IFN genes have been associated with response to infection. OBJECTIVES:This study was carried-out to investigate the association of IFNL3 gene polymorphisms (rs12979860 and rs8099917) with HBV susceptibility, in chronic HBV-infected patients. PATIENTS AND METHODS:In this case-control study, we determined IFNL3 single nucleotide polymorphisms (SNPs) (rs12979860 and rs8099917) in 221 individuals, with chronic HBV infection, and 200 healthy individuals, who were voluntary blood donors, with negative test for HBV. Alleles and genotypes analyses were performed by amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods. RESULTS:The frequencies of the rs12979860 and rs8099917 genotypes were not significantly different between the HBV-infected and the control groups (CC:CT:TT of 30.3%:48.0%:21.7% vs. 33.0%:49.0%:18.0%, P > 0.05, and GG:GT:TT of 5.8%:39.4%:54.8% vs. 5.0%:41.0%:54.0%, P > 0.05, respectively). Also, the frequencies of the alleles were not significantly different between both groups (C:T of 54.3%:45.7% vs. 57.5%:42.5%, P > 0.05, and G:T of 25.6%:74.4% vs. 25.5%:74.5%, P > 0.05, respectively) and the chronic HBV infection. There were no significant differences between patients, with at least one rs12979860C and or rs8099917T alleles compared to the healthy controls (rs12979860: CT + CC:TT, OR = 1.26, 95%CI = 0.78 - 2.04, P = 0.341 and rs8099917: GT + TT:GG, OR = 1.03, 95%CI = 0.70 - 1.51, P = 0.877, respectively). CONCLUSIONS:Our study showed no correlation between rs12979860 and rs8099917 SNPs and chronic HBV infection. Further studies, with larger sample sizes and different ethnicities, are necessary to validate our findings.

Project description:Hepatitis C virus (HCV) induces interferon (IFN) stimulated genes in the liver despite of distinct innate immune evasion mechanisms, suggesting that beyond HCV infected cells other cell types contribute to innate immune activation. Upon coculture with HCV replicating cells, human CD141+ myeloid dendritic cells (DC) produce type III IFN, whereas plasmacytoid dendritic cells (pDC) mount type I IFN responses. Due to limitations in the genetic manipulation of primary human DCs, we explored HCV mediated stimulation of murine DC subsets. Coculture of HCV RNA transfected human or murine hepatoma cells with murine bone marrow-derived DC cultures revealed that only Flt3-L DC cultures, but not GM-CSF DC cultures responded with IFN production. Cells transfected with full length or subgenomic viral RNA stimulated IFN release indicating that infectious virus particle formation is not essential in this process. Use of differentiated DC from mice with genetic lesions in innate immune signalling showed that IFN secretion by HCV-stimulated murine DC was independent of MyD88 and CARDIF, but dependent on TRIF and IFNAR signalling. Separating Flt3-L DC cultures into pDC and conventional CD11b-like and CD8α-like DC revealed that the CD8α-like DC, homologous to the human CD141+ DC, release interferon upon stimulation by HCV replicating cells. In contrast, the other cell types and in particular the pDC did not. Injection of human HCV subgenomic replicon cells into IFN-β reporter mice confirmed the interferon induction upon HCV replication in vivo. These results indicate that HCV-replicating cells stimulate IFN secretion from murine CD8α-like DC independent of infectious virus production. Thus, this work defines basic principles of viral recognition by murine DC populations. Moreover, this model should be useful to explore the interaction between dendritic cells during HCV replication and to define how viral signatures are delivered to and recognized by immune cells to trigger IFN release.

Project description:The negative regulators in the interferon (IFN) signaling pathway inhibit intrahepatic immune response, resulting in suboptimal therapeutic response to IFNα treatment in chronic hepatitis B (CHB) patients. Identifying the key negative factors and elucidating the regulating mechanism are essential for improving anti-HBV (hepatitis B virus) efficacy of IFNα. From the Gene Expression Omnibus (GEO) database, we downloaded and analyzed gene expression profiles of CHB patients with different responses to IFNα (GSE54747), and found that innate immune status was associated with the IFNα-based therapeutic response in CHB patients. Through PCR array, we found higher baseline level of IFN-induced transmembrane protein 2 (IFITM2) mRNA and lower baseline level of IFNα mRNA in peripheral blood mononuclear cells (PBMCs) of CHB patients with suboptimal response to IFNα treatment. Increased IFITM2 protein was also found in the serum of IFNα nonresponsive patients. With further experiments, we found that overexpressing IFITM2 in Huh7 cells suppressed endogenous IFNα synthesis by inhibiting phosphorylation of extracellular signal-regulated kinase (ERK), TANK-binding kinase 1 (TBK1), and interferon regulatory factor 3 (IRF3); knocking out IFITM2 enhanced activation of the endogenous IFNα synthesis pathway, exhibiting better inhibition on HBV replication. We also found that IFITM2 protein was shuttled by exosomes to dendritic cells (DCs), the main source of endogenous IFNα. Exosome-mediated transport of IFITM2 inhibited synthesis of endogenous IFNα in DCs whereas the inhibitory effect was abolished when IFITM2 was knocked out. Furthermore, we demonstrated that both palmitoylation inhibitor and mutation on 70/71 sites of IFITM2 protein influenced its incorporation into exosomes. Mutated IFITM2 protein increased the effect of IFNα against HBV. Conclusion: Exosome-mediated transport of IFITM2 to DCs inhibits IFNα pathway activation and blocks anti-HBV efficacy of exogenous IFNα. The findings provide an explanation to the suboptimal response of CHB patients to IFNα treatment.

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Human type 2 myeloid dendritic cells produce interferon-? and amplify interferon-? in response to hepatitis C virus infection.

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Human type 2 myeloid dendritic cells produce interferon-λ and amplify interferon-α in response to hepatitis C virus infection.

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