Canola oilseed- and Escherichia coli- derived hepatitis C virus (HCV) core proteins adjuvanted with oil bodies, induced robust Th1-oriented immune responses in immunized mice.

Induction of broad Th1 cellular immune responses and cytokines is crucial characteristics for vaccines against intracellular infections such as hepatitis C virus (HCV). Plants (especially oilseed tissues) and plant-immunomodulators (like oil bodies) offer cost-effective and scalable possibilities for the production of immunologically relevant and safe vaccine antigens and adjuvants, respectively. Herein, we provide data of the murine immunization by transgenic canola oilseed-derived HCV core protein (HCVcp) soluble extract (TSE) and Escherichia coli- derived rHCVcp in combination with Canola oil bodies (oil) compared to that of the Freund's (FA) adjuvant. Mice immunized by TSE+ oil developed both strong humeral (IgG) and Th1-biased cellular responses, manifested by high levels of IFN-γ and lower IgG1/IgG2a ratio and IL-4 secretion. Results of the intracellular cytokine staining indicated that TSE+ oil immunization in mice triggered both CD4+ and CD8+ T cells to release IFN-γ, while CD4+ cells were mostly triggered when FA was used. Analyses by qRT-PCR indicated that a combination of rHCVcp/TSE with oil body induced high levels of IL-10 cytokines compared to that of the FA adjuvant. These characteristics are important properties for the design of an HCV vaccine candidate and indicate the potential of Canola-derived antigen and oil bodies in addressing these concerns.

Viral Hepatitis and Human Immunodeficiency Virus Testing and Linkage to Care for Individuals Enrolled in an Opioid Treatment Program.

BACKGROUND: In the United States, many opioid treatment programs (OTPs) do not offer viral hepatitis (VH) or human immunodeficiency virus (HIV) testing despite high prevalence among OTP clients. We initiated an opt-out VH and HIV testing and linkage-to-care program within our OTP. METHODS: All OTP intakes are screened for VH and HIV and evaluated for rescreening annually. A patient navigator reviews laboratory results and provides counseling in the OTP clinic. The medical record is queried to identify individuals with previously diagnosed, untreated VH or HIV. Navigation support is provided for linkage or relinkage to VH or HIV care. RESULTS: Between March 2018 and Februrary 2019, 532 individuals were screened for hepatitis C virus (HCV), 180 tested HCV antibody positive (34%), and 108 were HCV-ribonucleic acid (RNA) positive (20%). Sixty individuals were identified with previously diagnosed, untreated HCV. Of all HCV RNA+, 49% reported current injection drug use (82 of 168). Ninety-five individuals were seen by an HCV specialist (57% of HCV RNA+), 72 started treatment (43%), and 69 (41%) completed treatment. Individuals with primary care providers were most likely to start treatment. Four individuals were diagnosed with hepatitis B; 0 were diagnosed with HIV. CONCLUSIONS: The implementation of an OTP-based screening and navigation protocol has enabled significant gains in the identification and treatment of VH in this high prevalence setting.

Integrating HCV testing with HIV programs improves hepatitis C outcomes in people who inject drugs: A cluster-randomized trial.

BACKGROUND & AIMS: There have been calls to integrate HCV testing into existing services, including harm reduction and HIV prevention and treatment, but there are few empirical trials to date. We evaluated the impact of integrating HCV testing/education into integrated care centers (ICCs) delivering HIV services to people who inject drugs (PWID) across India, using a cluster-randomized trial. METHODS: We compared ICCs with usual care in the PWID stratum (12 sites) of a 22-site cluster-randomized trial. In 6 sites, ICCs delivering HIV testing, harm reduction, other preventive services and linkage to HIV treatment were scaled from opioid agonist therapy centers and operated for 2 years. On-site rapid HCV antibody testing was integrated after 1 year. To assess impact, we conducted baseline and evaluation surveys using respondent-driven sampling (RDS) across the 12 sites (n = 11,993 recruited at baseline; n = 11,721 recruited at evaluation). The primary outcome was population-level self-reported HCV testing history. RESULTS: At evaluation, HCV antibody prevalence ranged from 7.2-76.6%. Across 6 ICCs, 5,263 ICC clients underwent HCV testing, of whom 2,278 were newly diagnosed. At evaluation, PWID in ICC clusters were 4-fold more likely to report being tested for HCV than in usual care clusters, adjusting for baseline testing (adjusted prevalence ratio [aPR] 3.69; 95% CI 1.34-10.2). PWID in ICC clusters were also 7-fold more likely to be aware of their HCV status (aPR 7.11; 95% CI 1.14-44.3) and significantly more likely to initiate treatment (aPR 9.86; 95% CI 1.52-63.8). CONCLUSIONS: We provide among the first empirical data supporting the integration of HCV testing into HIV/harm reduction services. To achieve elimination targets, programs will need to scale-up such venues to deliver comprehensive HCV services. CLINICALTRIALS. GOV IDENTIFIER: NCT01686750. LAY SUMMARY: Delivering hepatitis C virus (HCV) testing to people who inject drugs (PWID) in places where they also have access to HIV prevention and treatment services is an effective way to improve uptake of HCV testing among communities of PWID. To achieve the World Health Organization's ambitious elimination targets, integrated programs will need to be scaled up to deliver comprehensive HCV services.

Pre-clinical evaluation of a quadrivalent HCV VLP vaccine in pigs following microneedle delivery.

The introduction of directly acting antiviral agents (DAAs) has produced significant improvements in the ability to cure chronic hepatitis C infection. However, with over 2% of the world's population infected with HCV, complications arising from the development of cirrhosis of the liver, chronic hepatitis C infection remains the leading indication for liver transplantation. Several modelling studies have indicated that DAAs alone will not be sufficient to eliminate HCV, but if combined with an effective vaccine this regimen would provide a significant advance towards achieving this critical World Health Organisation goal. We have previously generated a genotype 1a, 1b, 2a, 3a HCV virus like particle (VLP) quadrivalent vaccine. The HCV VLPs contain the core and envelope proteins (E1 and E2) of HCV and the vaccine has been shown to produce broad humoral and T cell immune responses following vaccination of mice. In this report we further advanced this work by investigating vaccine responses in a large animal model. We demonstrate that intradermal microneedle vaccination of pigs with our quadrivalent HCV VLP based vaccine produces long-lived multi-genotype specific and neutralizing antibody (NAb) responses together with strong T cell and granzyme B responses and normal Th1 and Th2 cytokine responses. These responses were achieved without the addition of adjuvant. Our study demonstrates that our vaccine is able to produce broad immune responses in a large animal that, next to primates, is the closest animal model to humans. Our results are important as they show that the vaccine can produce robust immune responses in a large animal model before progressing the vaccine to human trials.

The efficiency of several one-step testing strategies for the diagnosis of hepatitis C.

BACKGROUND: implementing one-step strategies for hepatitis C diagnosis would help shorten the time to treatment access. Thus avoiding disease progression and complications, while facilitating hepatitis C virus (HCV) elimination. OBJECTIVE: to assess the validity and certainty of potential one-step strategies for the diagnosis of HCV infection and their associated cost and efficiency. METHODS: the study design is an economic appraisal of efficiency (cost/efficacy) using decision trees and deterministic sensitivity analysis. The analysis was performed from the payer perspective (Spanish National Health System), which exclusively considers the direct costs. Only the differential costs (diagnostic testing costs) were taken into account and the study was set in Spain. The efficacy of a diagnostic strategy was defined as the percentage of patients with an active HCV infection who received a positive diagnosis and the efficiency was defined as the cost per patient with a correctly diagnosed and active infection. RESULTS: the one-step strategies evaluated for the diagnosis of HCV had an acceptable validity and certainty due to the high sensitivity and specificity of the considered tests. The Ab-Ag strategy was the most efficient, followed by Ab-Ag-VL and Ab-VL. Ab-Ag was the most efficient due to the lower cost per patient tested, although the efficacy was lower than the Ab-VL efficacy. CONCLUSION: the study findings may help to establish more appropriate one-step diagnostic approaches whilst considering the efficacy and efficiency.

Hepatitis C Virus-Induced Myeloid-Derived Suppressor Cells Suppress NK Cell IFN-γ Production by Altering Cellular Metabolism via Arginase-1.

The hepatitis C virus (HCV) infects ∼ 200 million people worldwide. The majority of infected individuals develop persistent infection, resulting in chronic inflammation and liver disease, including cirrhosis and hepatocellular carcinoma. The ability of HCV to establish persistent infection is partly due to its ability to evade the immune response through multiple mechanisms, including suppression of NK cells. NK cells control HCV replication during the early phase of infection and regulate the progression to chronic disease. In particular, IFN-γ produced by NK cells limits viral replication in hepatocytes and is important for the initiation of adaptive immune responses. However, NK cell function is significantly impaired in chronic HCV patients. The cellular and molecular mechanisms responsible for impaired NK cell function in HCV infection are not well defined. In this study, we analyzed the interaction of human NK cells with CD33(+) PBMCs that were exposed to HCV. We found that NK cells cocultured with HCV-conditioned CD33(+) PBMCs produced lower amounts of IFN-γ, with no effect on granzyme B production or cell viability. Importantly, this suppression of NK cell-derived IFN-γ production was mediated by CD33(+)CD11b(lo)HLA-DR(lo) myeloid-derived suppressor cells (MDSCs) via an arginase-1-dependent inhibition of mammalian target of rapamycin activation. Suppression of IFN-γ production was reversed by l-arginine supplementation, consistent with increased MDSC arginase-1 activity. These novel results identify the induction of MDSCs in HCV infection as a potent immune evasion strategy that suppresses antiviral NK cell responses, further indicating that blockade of MDSCs may be a potential therapeutic approach to ameliorate chronic viral infections in the liver.

The Interplay between Zinc, Vitamin D and, IL-17 in Patients with Chronic Hepatitis C Liver Disease.

OBJECTIVES: To assess zinc (Zn) and vitamin D (Vit. D) status in chronic Hepatitis C virus- (HCV) infected patients and their relationship to interleukin- (IL-) 17 and disease severity and then investigate whether Zn and Vit. D3 modulate IL-17 expression in chronic HCV patients. METHODS: Seventy patients and fifty healthy subjects were investigated. Serum levels of Zn, Vit. D, and IL-17 were assessed in the patients group and subgroups. Patients lymphocytes were activated in vitro in the presence or absence of Zn or Vit. D3 and then intracellular IL-17 production was assessed using flow cytometry. RESULTS: Zn and Vit. D were significantly decreased in HCV patients. Increasing disease severity leads to more reduction in Zn level opposed by increasing IL-17 level. Zn potently reduced IL-17 production in a dose-related fashion; however it did not exert any toxic effects. Although Vit. D apparently increases IL17 expression, it is unclear whether it is due to its toxic effect on cell count or lack of definite association between Vit. D and both IL-17 and disease severity. CONCLUSIONS: This study demonstrates that Zn modulates IL-17 expression and provides a rationale for evaluating this compound as a supplementary agent in the treatment of chronic HCV.

Expression, immunogenicity and diagnostic value of envelope proteins from an Egyptian hepatitis C virus isolate.

The present work aimed at 1) characterization of the E1 and E2 proteins (HCV-E) from an Egyptian hepatitis C virus genotype 4a (HCV-4a) isolate at the molecular and immunological level, 2) in silico identification of the B- and T-cell epitopes responsible for the immunogenicity of HCV-E, and 3) evaluation of the diagnostic potential of both the recombinant HCV-E and antibodies raised using mammalian expression constructs encoding the protein. The region encoding the E1 and E2 proteins was amplified by RT-PCR from RNA isolated from blood of a human infected with HCV-4 and cloned into the pSC-TA plasmid, and the sequence was verified and used to construct a neighbor-joining phylogenetic tree. The translated nucleotide sequence was used to predict the HCV-E secondary structure using the PREDICT-PROTEIN server and PSI-PRED. A 3D model of HCV-E was generated using the online tool 3Dpro. B- and T-cell epitopes were predicted using the online tools BCPred and Epijen v1.0, respectively. The HCV-E-encoding sequence was later subcloned into the mammalian expression plasmid pQE, and the constructs that were generated were used to immunize mice in the absence and presence of adjuvants of plant origin. The maximum sequence identity obtained by nucleotide and protein BLAST analysis with previously published HCV-E sequences was 85 and 77 %, respectively. The B-cell epitope CFTPSPVVV at position 203 and the T-cell epitope ALSTGLIHL at position 380 were found to be highly conserved among all HCV genotypes. Both ELISA and Western blotting experiments on crude and purified recombinant HCV envelope proteins using mouse antisera raised using the HCV-E mammalian expression construct confirmed the specific antigenicity of the expressed protein. The antibodies raised in mice using the HCV-E-encoding construct could efficiently capture circulating antigens in patients' sera with good sensitivity that correlated with liver enzyme levels (r = 0.4052, P < 0.0001 for ALT; r = -0.5439, P = 0.0019 for AST). Moreover, combining the HCV-E-encoding construct with extracts prepared from Echinacea purpurea and Nigella sativa prior to immunizing mice significantly (P < 0.05) increased both the humoral (14.9- to 20-fold increase in antibodies) and the cellular (CD4(+) and cytotoxic CD8(+)- T lymphocytes) responses compared to mice that received the DNA construct alone or PBS-treated mice. Both recombinant HCV-E protein preparations and antibodies raised using the HCV-E-encoding mammalian expression construct represent useful diagnostic tools that can report on active HCV infection. Also, the immunostimulatory effects induced by the two plant extracts used at the cellular and humoral level highlight the potential of natural products for inducing protection against HCV infection. The neutralizing capacity of the induced antibodies is a subject of future investigations. Furthermore, the predicted B- and T-cell epitopes may be useful for tailoring future diagnostics and candidate vaccines against various HCV genotypes.

[Molecular aspects of the antiviral response against hepatitis C virus implicated in vaccines development]. / Aspectos moleculares de la respuesta antiviral contra el virus de la hepatitis C importantes para el desarrollo de vacunas.

Hepatitis C is a contagious liver disease caused by hepacivirus of the Flaviviridae family. It has a RNA genome, a unique highly variable molecule. It encodes ten proteins which are necessary to infect cells and multiply. Replication occurs only in hepatocytes. Because of its wide genomic variability and the absence of symptoms, it is difficult to make an early diagnosis and successful treatment. In this review we analyze the molecular mechanism by which the virus infects the hepatocytes and causes the disease. We focused the analysis on different therapies, with the possibility of improving treatment with the use of new specific vaccines. We highlight the use of new therapies based on nucleic acids, mainly DNA vectors. In the near future, once this treatment is adequately evaluated in clinical trials, and the costs are calculated, it could be a very beneficial alternative to conventional methods.

Hepatitis C vaccine. Need of the hour.

Hepatitis C virus (HCV) was first identified in 1989. HCV is a small, enveloped RNA virus. Globally, 3-4 million persons are infected with HCV each year, and are at risk of developing liver cirrhosis and/or liver cancer. The common modalities of the spread of hepatitis C infection are blood transfusions, injection drug use, unsafe therapeutic injections, and healthcare-related procedures. The standard treatment for hepatitis C has been combination antiviral therapy with interferon (IFN) and ribavirin, which are effective against all the genotypes of hepatitis viruses (pan-genotypic). A 12-month course of Peg-IFN/ribavirin treatment costs > $20 000. New HCV-specific antiviral drugs, especially in combination, have shown very high cure rates; however, the annual cost for a single subject ($82 000) make these unaffordable in most of the world. There is no hepatitis C vaccine. However, several vaccines in development, and some have shown promising preclinical results. Over the last few years, numerous HCV vaccine approaches have been assessed in mice and primates, but only a few vaccines have progressed to human trials. The challenge to develop HCV vaccine is to move into larger at-risk or infected populations to test efficacy.

Hepatitis C virus hypervariable region 1 variants presented on hepatitis B virus capsid-like particles induce cross-neutralizing antibodies.

Hepatitis C virus (HCV) infection is still a serious global health burden. Despite improved therapeutic options, a preventative vaccine would be desirable especially in undeveloped countries. Traditionally, highly conserved epitopes are targets for antibody-based prophylactic vaccines. In HCV-infected patients, however, neutralizing antibodies are primarily directed against hypervariable region I (HVRI) in the envelope protein E2. HVRI is the most variable region of HCV, and this heterogeneity contributes to viral persistence and has thus far prevented the development of an effective HVRI-based vaccine. The primary goal of an antibody-based HCV vaccine should therefore be the induction of cross-reactive HVRI antibodies. In this study we approached this problem by presenting selected cross-reactive HVRI variants in a highly symmetric repeated array on capsid-like particles (CLPs). SplitCore CLPs, a novel particulate antigen presentation system derived from the HBV core protein, were used to deliberately manipulate the orientation of HVRI and therefore enable the presentation of conserved parts of HVRI. These HVRI-CLPs induced high titers of cross-reactive antibodies, including neutralizing antibodies. The combination of only four HVRI CLPs was sufficient to induce antibodies cross-reactive with 81 of 326 (24.8%) naturally occurring HVRI peptides. Most importantly, HVRI CLPs with AS03 as an adjuvant induced antibodies with a 10-fold increase in neutralizing capability. These antibodies were able to neutralize infectious HCVcc isolates and 4 of 19 (21%) patient-derived HCVpp isolates. Taken together, these results demonstrate that the induction of at least partially cross-neutralizing antibodies is possible. This approach might be useful for the development of a prophylactic HCV vaccine and should also be adaptable to other highly variable viruses.

Toll-like receptor 8 agonist and bacteria trigger potent activation of innate immune cells in human liver.

The ability of innate immune cells to sense and respond to impending danger varies by anatomical location. The liver is considered tolerogenic but is still capable of mounting a successful immune response to clear various infections. To understand whether hepatic immune cells tune their response to different infectious challenges, we probed mononuclear cells purified from human healthy and diseased livers with distinct pathogen-associated molecules. We discovered that only the TLR8 agonist ssRNA40 selectively activated liver-resident innate immune cells to produce substantial quantities of IFN-γ. We identified CD161(Bright) mucosal-associated invariant T (MAIT) and CD56(Bright) NK cells as the responding liver-resident innate immune cells. Their activation was not directly induced by the TLR8 agonist but was dependent on IL-12 and IL-18 production by ssRNA40-activated intrahepatic monocytes. Importantly, the ssRNA40-induced cytokine-dependent activation of MAIT cells mirrored responses induced by bacteria, i.e., generating a selective production of high levels of IFN-γ, without the concomitant production of TNF-α or IL-17A. The intrahepatic IFN-γ production could be detected not only in healthy livers, but also in HBV- or HCV-infected livers. In conclusion, the human liver harbors a network of immune cells able to modulate their immunological responses to different pathogen-associated molecules. Their ability to generate a strong production of IFN-γ upon stimulation with TLR8 agonist opens new therapeutic opportunities for the treatment of diverse liver pathologies.

Hepatitis C screening trends in a large integrated health system.

BACKGROUND: As new hepatitis C virus (HCV) therapies emerge, only 1%-12% of individuals are screened in the US for HCV infection. Presently, HCV screening trends are unknown. METHODS: We utilized the Kaiser Permanente Mid-Atlantic States' (KPMAS) data repository to investigate HCV antibody screening between January 1, 2003 and December 31, 2012. We identified the proportion screened for HCV and 5-year cumulative incidence of screening, the screening positivity rate, the provider types performing HCV screening, patient-level factors associated with being screened, and trends in screening over time. RESULTS: There were 444,594 patients who met the inclusion criteria. Overall, 15.8% of the cohort was ever screened for HCV. Adult primary care and obstetrics and gynecology providers performed 75.9% of all screening. The overall test positivity rate was 3.8%. Screening was more frequent in younger age groups (P <.0001) and those with a documented history of illicit drug use (P <.0001). Patients with missing drug use history (46.7%) were least likely to be screened (P <.0001). While the rate of HCV screening increased in the later years of the study among those enrolled in KPMAS 2009-2012, only 11.8% were screened by the end of follow-up. CONCLUSION: Screening for HCV is increasing but remains incomplete. Targeting screening to those with a history of injection drug will not likely expand screening, as nearly half of patients have no documented drug use history. Routine screening is likely the most effective approach to expand HCV screening.

Economic assessment of an anti-HCV screening program in Italy.

BACKGROUND: The progression of hepatitis C virus (HCV) disease usually occurs over a 10-year period. HCV-related complications as well as the highly debilitating effects on patients represent a significant item of expenditure for the National Health Service. Early detection of HCV infection is an excellent opportunity to improve patients' quality of life and to rationalize resource allocation. OBJECTIVE: The aim of this study was to provide a cost-effectiveness evaluation of an anti-HCV screening program in the Italian National Health Service perspective. METHODS: We built a Markov model made up of two arms. The ''Test Strategy'' arm involves a screening program based on the enzyme immunoassay for detection of antibodies as first-level test and the research of HCV RNA as second-level detection; patients with positive test results are treated with peg-interferon alfa in combination with ribavirine. Parameters were derived from the literature and validated through experts' opinion. Costs and benefits were discounted by 3.5%. Results were expressed as cost/quality-adjusted life-year (QALY) gained through the screening program compared with the treatment of symptomatic patients. Deterministic and probabilistic sensitivity analysis was performed. RESULTS: The incremental cost-effectiveness ratio of the ''Test Strategy'' is €5171/QALY, definitively below the cost/QALY of other approved treatments in Italy. Model results turned out as sensitive to the age of the target population, the prevalence of HCV infection, and the time horizon adopted. CONCLUSIONS: The anti-HCV screening program is a valid health-related investment improving patients' quality of life and survival with an acceptable expenditure increase for the National Health Service.

Prospects for prophylactic hepatitis C vaccines based on virus-like particles.

Given the global prevalence and long-term complications of chronic hepatitis C virus (HCV) infection, HCV constitutes one of the greatest challenges to human health of this decade. Considerable efforts have focused on the development of new effective treatments, but about three to four million individuals become infected each year, adding to the world reservoir of HCV infection. The development of a prophylactic vaccine against hepatitis C virus has thus become an important medical priority. Only a few vaccine candidates have progressed to the clinical phase, and published data on both the efficacy and safety of these vaccines are limited, due to many scientific, logistic and bioethic challenges. Fortunately, new innovative vaccine formulations, modes of vaccination and delivery technologies have been developed in recent years. Several preclinical trials of virus-like particle (VLP)-based vaccination strategies are currently underway and have already generated very promising results. In this commentary, we consider the current state of prophylactic HCV vaccines, the hurdles to be overcome in the future and the various VLP-based vaccination approaches currently being developed.

Clonal expansion and functional exhaustion of monoclonal marginal zone B cells in mixed cryoglobulinemia: the yin and yang of HCV-driven lymphoproliferation and autoimmunity.

Monoclonal marginal zone (MZ) B cells expressing a V(H)1-69-encoded idiotype accumulate in HCV-associated mixed cryoglobulinemia (MC). These cells recognize the E2 protein of HCV and their massive clonal expansion reflects the propensity of MZ B cells to proliferate robustly upon antigenic stimulation by microorganisms, a property that makes them prone to neoplastic transformation. V(H)1-69(+) B cells of MC patients are phenotypically heterogeneous and resemble either mature MZ B cells (IgM(+)CD27(+)CD21(high)) or the unusual CD21(low) B cells that accumulate in other immunological disorders such as common variable immunodeficiency (CVID) or HIV infection. The CD21(low) V(H)1-69(+) B cells of MC patients, like those of CVID and HIV patients, are anergic to BCR and TLR9 stimulation and display deregulation of several anergy-related genes; proliferative anergy is also observed in CD21(high) MZ-like V(H)1-69(+) B cells, that over-express the antiproliferative transcriptional repressor Stra13. Upon evolution to splenic marginal zone lymphoma, MZ-like V(H)1-69(+) B cells down-regulate Stra13 and partially recover their capacity to proliferate in response to TLR9 ligation. Like yin and yang, robust clonal expansion and early proliferative anergy may be viewed as the opposite forces balancing the responses of human MZ B cells to chronic microbial stimuli. Disruption of this balance facilitates autoimmunity and lymphoproliferation.

[Influence of immunotropic preparation cycloferon and phytopreparations of Cynara scolimus L. on blood cytokines profile of the patients with chronic viral hepatitis C in medical rehabilitation period].

The effect of the immunotropic drug cycloferon and herbal medicine resources on the basis of Cynara scolimus L. on the blood cytokine profile in the patients with chronic viral hepatitis C (CVHC) in medical rehabilitation (MR) period. Established that prior to MR period in the patients with CVHC was noted significantly increased levels of proinflammatory cytokines (CK) at the blood serum, and the level of antiinflammatory CK changed significantly. The use of cycloferon and herbal medicine resources on the basis of Cynara scolimus L. in the MR complex provided to normalize the studied CK concentration in the serum of the patients with CVHC.

Preclinical development of TLR ligands as drugs for the treatment of chronic viral infections.

INTRODUCTION: Toll-like receptors (TLRs) have been identified as key regulators of innate and adaptive immune responses in viral infection. Recent progress in this field revealed that there are significant interactions between the TLR system and pathogens in chronic viral infections. Therefore, TLR ligands have great potential for the treatment of chronic viral infections. AREAS COVERED: This review provides an overview of the methodology for preclinical testing of TLR ligands for three major viral infections: hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV). TLR ligands have shown potent antiviral activity in different cell culture systems as well as animal models for these infections and induce the production of antiviral cytokines, modulated cellular immunological functions and antiviral effects in vivo. EXPERT OPINION: The recent progress in this field demonstrated that activation of a large number of TLR ligands is effective against viral infections in cell culture systems and animal models. Exploring these models, further in-depth elucidation of the molecular and immunological mechanisms of the antiviral activity of TLR ligands will be necessary to develop them into clinical useful drugs.

Classical and emerging roles of vitamin D in hepatitis C virus infection.

According to the Institute of Medicine, the risk of clinically significant vitamin D deficiency increases at 25-hydroxyvitamin D levels below 20 ng/mL. By this standard, most cirrhotic hepatitis C virus- (HCV-) positive patients and many noncirrhotic patients are vitamin D-deficient. The high prevalence of vitamin D deficiency among HCV patients is a cause for concern for several specific reasons. Classic studies established the importance of vitamin D and calcium in maintaining bone. Vitamin D's beneficial effects on bone are likely to be vital for HCV-infected patients because these individuals have a high prevalence of low bone mineral density. Many pharmaceutical agents reduce bone density and exposure to these drugs may increase bone disease in HCV-positive patients. Bone loss occurs following liver transplantation and bone density is often low in patients with HIV/HCV co-infection who are on combination antiretroviral therapy. Some evidence suggests that ribavirin reduces bone density, underscoring the special need to monitor vitamin D in patients receiving HCV treatment and to prescribe supplements, as appropriate. In addition to its role in calcium metabolism, vitamin D is also an immune modulator that reduces inflammation while enhancing protective immune responses. Higher vitamin D levels are associated with less liver fibrosis and less inflammation in HCV patients. Recent studies show that low vitamin D levels are associated with treatment failure among HCV-infected patients receiving pegylated-interferon and ribavirin. If confirmed, these findings will provide an additional reason to ensure adequate levels of vitamin D. Information about how to monitor vitamin D status and how to use vitamin D supplements most effectively in HCV-infected patients is provided.

[Investigation of HCV multi-epitope gene vaccine loaded by CTS-Fe3O4].

OBJECTIVE: In order to develop a promising HCV gene vaccine candidate to induce effective immune response and explore the application of magnetic nanoparticles as gene delivery system. METHODS: The DNA fragment containing multi-epitope antigen gene of HCV with five conserved mimotopes was synthesized and cloned into plasmid pcDNA3.1 (+). The Fe3O4 modified with chitoson was prepared and the cytotoxicity of the magnetic material was detected in vitro. Analysis of recombinant plasmid in vitro expression, and its immunogenicity loaded by CTS-Fe3O4 in mice were evaluated in detail. RESULTS: The HCV multi-epitope gene vaccine pcDNA3.1 (+)-MA was successfully constructed and recognized by 81% HCV positive sera. There was no cytotoxicity of CTS-Fe3O4 when its concentration was equal or less than 1 mmol/L. Both the antibody production and T-cell activity were induced. CONCLUSION: It was believed that DNA encoding MA was an attractive approach for the therapeutic and prophylactic vaccines against HCV and the Fe3O4 modified with chitoson showed excellent target, safety and adjuvant effect as gene carrier.