Differential Specificity of Interferon-alpha Inducible Gene Expression in Association with Human Immunodeficiency Virus and Hepatitis C Virus Levels and Declines in vivo.

OBJECTIVE: This study was aimed to correlate in vivo interferon (IFN) inducible gene (IFIG) expression and IFIG induction with viral-load (VL) and VL-kinetics of Human-Immunodeficiency-Virus (HIV) or Hepatitis-C-Virus (HCV) in HIV-positive patients treated with pegylated IFN-alpha-2a (PegIFNα). METHODS: HIV mono-infected patients (N=8) and HIV/HCV co-infected patients (N=23, without HIV-viremia) were treated with PegIFNα (180 µg/week) for 12 and 48 weeks, respectively. Blood sampling for monitoring IFIG expression occurred at day_0 and week_3, _6 and _12 for HIV mono-infected patients vs. only at day_0 and week_48 for HIV/HCV co-infected subjects. IFIG expression (N=20) was measured in peripheral blood mononuclear cells by bDNA-assay. VL levels/changes in plasma were analyzed for correlation with IFIG expression/induction at/between selected time points. Overall, P<0.05 was considered significant. RESULTS: None of the 20 IFIG expression profiles at day_0 correlated significantly with HIV-VL at day_0. Expression at day_0 of 3 IFIG (APOBEC3G/OAS1/OAS2) correlated significantly (r>+0.42/P<0.05) with HCV-VL at day_0. The strongest antiviral effect [measured as median viral decline per week: ΔVL/week (log10)] occurred in common against HIV and HCV between day_0 and week_3 during 12 weeks of continuous PegIFNα treatment in both cohorts. Expression at day_0 of 1 IFIG (APOBEC3A) correlated significantly (r<-0.71/P<0.05) with HIV-ΔVL/week (log10) from day_0 to week_3. No significance was reached in correlations between expression values of 20 IFIG at day_0 and HCV-ΔVL/week (log10) from day_0 to week_3. No significant correlation was detected between IFIG expression changes (ΔIFIG=induction) from day_0 to week_3 and HIV-ΔVL/week (log10) from day_0 to week_3. Interestingly, induction of 1 IFIG (ΔISG20) from day_0 to week_48 was significantly associated (P<0.05) with permanent HCV clearance. CONCLUSION: This study demonstrates the differential specificity of PegIFNα mediated molecular actions by dissecting the kinetics of IFIG expression and induction, suggesting multiple, possibly non-overlapping mechanisms for antiviral effects against HCV and HIV.

Interleukin-27, an anti-HIV-1 cytokine, inhibits replication of hepatitis C virus.

Interleukin (IL)-27 is a member of IL-12 family cytokine. We have previously reported that IL-27 inhibits human immunodeficiency virus type-1 (HIV-1) replication in CD4(+) T cells and monocyte-derived macrophages, even though IL-12 enhances HIV-1 replication in primary CD4(+) T cells. Further study demonstrates that IL-27 induces antiviral genes including RNA-dependent protein kinase, oligoadenylate synthetase, and myxovirus protein in the same manner as interferon (IFN)-alpha. Neutralization assay using anti-IFN antibodies, real-time RT-PCR, and enzyme-linked immunosorbent assay demonstrated that IL-27 induces the antiviral genes without the induction of IFNs. IFN-alpha has been administered to hepatitis C virus (HCV)-infected patients as well as HCV/HIV-1 co-infected patients. Despite the improved immunotherapy, some patients are still failed to respond to the treatment. Since IL-27 induces IFN-alpha-like responses including the induction of antiviral genes, it was speculated that IL-27 may impact the replication of HCV. In this study, we evaluated the role of IL-27 on HCV replication using Huh7.5, an HCV permissive cell line. IL-27 induces STAT-1 and -3 in the cell line, and dose-dependently inhibited HCV. These data suggest that IL-27 may play a role in the development of a novel immunotherapeutic strategy for HCV and HCV/HIV co-infection.

Altered regulation of extrinsic apoptosis pathway in HCV-infected HCC cells enhances susceptibility to mapatumumab-induced apoptosis.

BACKGROUND: Hepatitis C virus (HCV)-infected patients, including those co-infected with human immunodeficiency virus (HIV), are at increased risk of developing hepatocellular carcinoma (HCC). We evaluated the ability of agonistic human monoclonal antibodies to tumor necrosis factor-related apoptosis inducing ligand (TRAIL) receptors, mapatumumab and lexatumumab, respectively, to induce TRAIL-receptor mediated apoptosis (TRMA) in HCC (HCV-infected and -uninfected) cells and in peripheral blood cells (HIV-infected and -uninfected). METHODS: Susceptibility to antibody-mediated TRMA was measured by caspase 3/7 activity and by confocal microscopy. Surface expression of receptors on HCV-uninfected and -infected Huh7.5 cells was measured by flow cytometry and confocal microscopy. Inhibitor of Apoptosis Protein (IAP) RNA levels were quantified by RT-PCR. DNA Microarray was performed using RNA isolated from Huh7.5 cells (HCV-infected and uninfected) using Affymetrix U133A chips. RESULTS: Mapatumumab preferentially induces TRMA of HCV-infected Huh7.5 cells by binding to TRAIL-R1. Higher basal expression of TRAIL-R2 compared to that of TRAIL-R1 on HCV-uninfected Huh7.5 cells were observed. Lexatumumab induces TRMA of both HCV-infected and -uninfected cells by binding to TRAIL-R2. IFN-alpha has minimal effect on mapatumumab- and lexatumumab-induced TRMA. HCV infection of Huh7.5 cells up-regulates TRAIL-R1 expression and X-linked Inhibitor of apoptosis protein and survivin gene expression. Neither antibody had a pro-apoptotic effect on PBMCs from patients with HIV infection ex vivo. CONCLUSION: Both mapatumumab and lexatumumab are excellent candidates for therapy of HCC. HCV infection of Huh7.5 cells selectively up-regulates TRAIL-R1 receptor, associated with increased susceptibility to mapatumumab-mediated TRMA. HCV infection up-regulated IAP genes, offering promise for future combination therapy using TRAIL agonists and IAP inhibitors.