Hepatitis C virus (HCV) is one of the main causes of chronic liver disease. Although infection of hepatocytes is mainly responsible for manifestations of hepatitis C, the virus also invades the immune system by a yet-to-be-identified mechanism. Using human T cell lines and primary T lymphocytes as targets and patient-derived HCV as inocula, we aimed to identify how HCV gains entry into these cells. HCV replication was determined by detection of the HCV RNA replicative (negative) strand and viral proteins, while specific antibodies, knocking down gene expression and making otherwise-resistant cells prone to HCV, were employed to identify a receptor molecule determining T lymphocyte permissiveness to HCV infection. The results revealed that T cell susceptibility to HCV requires CD5, a lymphocyte-specific glycoprotein belonging to the scavenger receptor cysteine-rich family. Blocking of T cell CD5 with antibody or silencing with specific short hairpin RNA (shRNA) decreased cell susceptibility to HCV, while increasing CD5 expression by mitogen stimulation had the opposite effect. Moreover, transfection of naturally CD5-deficient HEK-293 fibroblasts with CD5 facilitated infection of these otherwise HCV-resistant cells. In contrast to T cells, hepatocytes do not express CD5. The data revealed that CD5 is a molecule important for HCV entry into human T lymphocytes. This finding provides direct insight into the mechanism of HCV lymphotropism and defines a target for potential interventions against HCV propagating in this extrahepatic compartment.

MS progression was consistently associated with low vitamin D levels, and smoking was associated with a more rapid decline in MS disability. Studies used a variety of methods, predictors, and outcomes making it difficult to draw conclusions. Future studies should focus on prospective assessments.

BackgroundHepatitis C virus (HCV) can replicate in cells of the immune system and productively propagate in primary T lymphocytes in vitro. We aimed to determine whether exposure to authentic, patient-derived HCV can modify the proliferation capacity, susceptibility to apoptosis and phenotype of T cells.MethodsPrimary total T cells from a healthy donor were used as targets and plasma-derived HCV from patients with chronic hepatitis C served as inocula. T cell phenotype was determined prior to and at different time points after exposure to HCV. T cell proliferation and apoptosis were measured by flow cytometry-based assays.ResultsThe HCV inocula that induced the highest intracellular expression of HCV also caused a greatest shift in the T cell phenotype from predominantly CD4-positive to CD8-positive. This shift was associated with inhibition of CD4+ but not CD8+ T cell proliferation and did not coincide with altered apoptotic death of either cell subset.ConclusionsThe data obtained imply that exposure to native HCV can have an impact on the relative frequencies of CD4+ and CD8+ T cells by selectively suppressing CD4+ T lymphocyte proliferation and this may occur in both the presence and the absence of measurable HCV replication in these cells. If the virus exerts a similar effect in vivo, it may contribute to the impairment of virus-specific T cell response by altering cooperation between immune cell subsets.Electronic supplementary materialThe online version of this article (doi:10.1186/s12985-015-0322-4) contains supplementary material, which is available to authorized users.

Resolution of chronic hepatitis C is considered when serum HCV RNA becomes repeatedly undetectable and liver enzymes normalize. However, long-term persistence of HCV following therapy with pegylated interferon-α/ribavirin (PegIFN/R) was reported when more sensitive assays and testing of serial plasma, lymphoid cells (PBMC) and/or liver biopsies was applied. Our aim was to reassess plasma and PBMCs collected during and after standard PegIFN/R therapy from individuals who became HCV RNA nonreactive by clinical testing. Of particular interest was to determine if HCV genome and its replication remain detectable during ongoing treatment with PegIFN/R when evaluated by more sensitive detection approaches. Plasma acquired before (n = 11), during (n = 25) and up to 12–88 weeks post-treatment (n = 20) from 9 patients and PBMC (n = 23) from 3 of them were reanalyzed for HCV RNA with sensitivity <2 IU/mL. Clone sequencing of the HCV 5′-untranslated region from plasma and PBMCs was done in 2 patients. HCV RNA was detected in 17/25 (68%) plasma and 8/10 (80%) PBMC samples collected from 8 of 9 patients during therapy, although only 5.4% plasma samples were positive by clinical assays. Among post-treatment HCV RNA-negative plasma samples, 9 of 20 (45.3%) were HCV reactive for up to 59 weeks post-treatment. Molecularly evident replication was found in 6/12 (50%) among PBMC reactive for virus RNA positive strand collected during or after treatment. Pre-treatment point mutations persisted in plasma and/or PBMC throughout therapy and follow-up. Therefore, HCV is not completely cleared during ongoing administration of PegIFN/R otherwise capable of ceasing progression of CHC and virus commonly persists at levels not detectable by the current clinical testing. The findings suggest the need for continued evaluation even after patients achieve undetectable HCV RNA post-treatment.

We did not identify any risk factor interventions with significant effects on MS progression, but the overall QoE was limited. More adequately powered trials are needed on vitamin D supplementation, long-term exercise, and smoking cessation.

Hepatitis C virus (HCV) frequently causes chronic hepatitis, while spontaneous recovery from infection is infrequent. Persistence of HCV after self-limited (spontaneous) resolution of hepatitis C was rarely investigated. The current study aimed to assess incidence and robustness of HCV persistence after self-resolved hepatitis C in individuals with normal liver enzymes and undetectable virus by conventional tests. Applying high sensitivity HCV RNA detection approaches, we analyzed plasma and peripheral blood mononuclear cells (PBMC) from individuals with previous hepatitis C infection. Parallel plasma and PBMC from 24 such non-viraemic individuals followed for 0.3–14.4 (mean 6.4) years were examined. Additional samples from 9 of them were obtained 4.5–7.2 (mean 5.9) years later. RNA was extracted from 250 μl plasma and, if HCV negative, from ~5 ml after ultracentrifugation, and from ex vivo stimulated PBMC. PBMC with evidence of HCV replication from 4 individuals were treated with HCV protease inhibitor, telaprevir. HCV RNA was detected in 14/24 (58.3%) plasma and 11/23 (47.8%) PBMC obtained during the first collection. HCV RNA replicative strand was evident in 7/11 (63.6%) PBMC. Overall, 17/24 (70.8%) individuals carried HCV RNA at mean follow-up of 5.9 years. Samples collected 4.5–7.2 years later revealed HCV in 4/9 (44.4%) plasma and 5/9 (55.5%) PBMC, while 4 (80%) of these 5 PBMC demonstrated virus replicative strand. Overall, 6/9 (66.7%) individuals remained viraemic for up to 20.7 (mean 12.7) years. Telaprevir entirely eliminated HCV replication in the PBMC examined. In conclusion, our results indicate that HCV can persist long after spontaneous resolution of hepatitis C at levels undetectable by current testing. An apparently effective host immune response curtailing hepatitis appears insufficient to completely eliminate the virus. The long-term morbidity of asymptomatic HCV carriage should be examined even in individuals who achieve undetectable HCV by standard testing and their need for treatment should be assessed.

Accumulated evidence implies that hepatitis C virus (HCV) infects not only the liver but also the immune system. A lymphocyte-specific CD5 molecule was recently identified as essential for infection of T cells with native, patient-derived HCV. To assess whether the proposed hepatocyte receptors may also contribute to HCV lymphotropism, expression of scavenger receptor-class B type 1 (SR-B1), claudin-1 (CLDN-1), claudin-6 (CLDN-6), occludin (OCLN), CD5 and CD81 was examined by real-time RT-PCR and the respective proteins quantified by immunoblotting in HCV-prone and resistant T cell lines, peripheral blood mononuclear cells (PBMC), primary T cells and their subsets, and compared to hepatoma Huh7.5 and HepG2 cells. SR-B1 protein was found in T and hepatoma cell lines but not in PBMC or primary T lymphocytes, CLDN-1 in HCV-resistant PM1 T cell line and hepatoma cells only, while CLDN-6 equally in the cells investigated. OCLN protein occurred in HCV-susceptible Molt4 and Jurkat T cells and its traces in primary T cells, but not in PBMC. CD5 was displayed by HCV-prone T cell lines, primary T cells and PBMC, but not by non-susceptible T and hepatoma cell lines, while CD81 in all cell types except HepG2. Knocking-down OCLN in virus-prone T cell line inhibited HCV infection, while de novo infection downregulated OCLN and CD81, and upregulated CD5 without modifying SR-B1 expression. Overall, while no association between SR-B1, CLDN-1 or CLDN-6 and the susceptibility to HCV was found, CD5 and CD81 expression coincided with virus lymphotropism and that of OCLN with permissiveness of T cell lines but unlikely primary T cells. This study narrowed the range of factors potentially utilized by HCV to infect T lymphocytes amongst those uncovered using laboratory HCV and Huh7.5 cells. Together with the demonstrated role for CD5 in HCV lymphotropism, the findings indicate that virus utilizes different molecules to enter hepatocytes and lymphocytes.

There is a tremendous focus on the application of nanomaterials for the treatment of cancer. Nonprimate models are conventionally used to assess the biomedical utility of nanomaterials. However, these animals often lack an intact immunological background, and the tumors in these animals do not develop spontaneously. We introduce a preclinical woodchuck hepatitis virus-induced liver cancer model as a platform for nanoparticle (NP)-based in vivo experiments. Liver cancer development in these out-bred animals occurs as a result of persistent viral infection, mimicking human hepatitis B virus-induced HCC development. We highlight how this model addresses key gaps associated with other commonly used tumor models. We employed this model to (1) track organ biodistribution of gold NPs after intravenous administration, (2) examine their subcellular localization in the liver, (3) determine clearance kinetics, and (4) characterize the identity of hepatic macrophages that take up NPs using RNA-sequencing (RNA-seq). We found that the liver and spleen were the primary sites of NP accumulation. Subcellular analyses revealed accumulation of NPs in the lysosomes of CD14+ cells. Through RNA-seq, we uncovered that immunosuppressive macrophages within the woodchuck liver are the major cell type that take up injected NPs. The woodchuck-HCC model has the potential to be an invaluable tool to examine NP-based immune modifiers that promote host anti-tumor immunity.