Circulating viral core and E1 antigen levels as supplemental markers for HCV chronic hepatitis

Developments in the HCV Screening Technologies Based on the Detection of Antigens and Antibodies

Hepatitis C virus (HCV) accounts for 15%-20% of cases of acute infection, and chronic HCV infection is developed in about 50%-80% of HCV patients. Unfortunately, due to the lack of proper medical care, difficulty in screening for HCV infection, and lack of awareness resulted in chronic HCV infection in 71 million people on a global scale, and about 399,000 deaths in 2016. It is crucial to recognize that the effective use of antiviral medicines can cure more than 95% of HCV infected people. The Global Health Sector Strategy (GHSS) aim is to reduce the new HCV infections and the HCV associated mortality by 90% and 65%, respectively. Therefore, the methods that are simple, yet powerful enough to detect HCV infections with high sensitivity, specificity, and a shorter window period are crucial to restrain the global burden of HCV healthcare. This article focuses on the technologies used for the detection of HCV in clinical specimens.

Insufficiency of DNA repair enzyme ATM promotes naive CD4 T-cell loss in chronic hepatitis C virus infection

T cells have a crucial role in viral clearance and vaccine response; however, the mechanisms regulating their responses to viral infections or vaccinations remain elusive. In this study, we investigated T-cell homeostasis, apoptosis, DNA damage, and repair machineries in a large cohort of subjects with hepatitis C virus (HCV) infection. We found that naive CD4 T cells in chronically HCV-infected individuals (HCV T cells) were significantly reduced compared with age-matched healthy subjects. In addition, HCV T cells were prone to apoptosis and DNA damage, as evidenced by increased 8-oxoguanine expression and γH2AX/53BP1-formed DNA damage foci-hallmarks of DNA damage responses. Mechanistically, the activation of DNA repair enzyme ataxia telangiectasia mutated (ATM) was dampened in HCV T cells. ATM activation was also diminished in healthy T cells exposed to ATM inhibitor or to HCV (core protein) that inhibits the phosphoinositide 3 kinase pathway, mimicking the biological effects in HCV T cells. Importantly, ectopic expression of ATM was sufficient to repair the DNA damage, survival deficit, and cell dysfunctions in HCV T cells. Our results demonstrate that insufficient DNA repair enzyme ATM leads to increased DNA damage and renders HCV T cells prone to apoptotic death, which contribute to the loss of naive T cells in HCV infection. Our study reveals a novel mechanism for T-cell dysregulation and viral persistence, providing a new strategy to improve immunotherapy and vaccine responses against human viral diseases.

Antiviral activity of virocidal peptide derived from NS5A against two different HCV genotypes: an in vitro study

This study aimed at assessment of the antiviral activity of an amphipathic α-helical peptide derived from the hepatitis C virus NS5A known as C5A virocidal peptide against different HCV genotypes. Two sources of HCV virus for in vitro study: HCV genotype 4 sera samples and JFH-1 infectious culture system genotype 2a were used. Several virocidal peptide concentrations were tested to determine the concentration that inhibits HCV propagation in Huh 7.5 cells according to three different prortocols (pre-infection, coinfection, and post infection). The capacity of the virocidal peptide to block HCV in Huh7.5 cells infected with different 10 individual serum samples was evaluated. In the pre-infection protocol, virocidal concentration (20, 50, and 75 μM) showed no viral RNA. In the co-infection protocol, virocidal concentrations (10, 20, 50, 75 μM) showed no viral RNA while in post-infection protocol, 75 μM was the only concentration that blocked the HCV activity. Results of Huh7.5 cell line transfected with HCV cc J6/JFH and treated with virocidal peptide revealed that only the higher virocidal concentration (75 μM) showed no amplification. The percentage of virocidal blocking in the 10 HCV individual serum samples was 60%. In conclusion, the C5A virocidal peptide has potent antiviral activity against HCV.

Relationship between humoral response against hepatitis C virus and disease overcome

Abstract

Hepatitis C virus infection leads to liver disease whose severity can range from mild to serious lifelong illness. However the parameters involved in the evolution of the disease are still unknown. Among other factors, the virus-elicited antibody profile is suspected to play a role in the outcome of the disease. Analysis of the relationship between anti-virus antibodies and disease state requires the analysis of a large number of serums from patients (hepatitis C virus+) and of epitopes from the viral proteins. Such a study would benefit from microarray-based screening systems that are appropriate for high-throughput assays.

We used a method combining peptide chips and surface plasmon resonance imaging previously shown to be suitable for analyzing complex mediums and detecting peptide-protein interactions. 56 peptides covering the entire viral proteome were grafted on chips and their interaction with antibodies present in the 68 injected serums from infected and non-infected donors was measured. Statistical analyses were conducted to determine a possible relationship between antibodies (specificity and amount) and disease states.

A good discrimination between infected and non-infected donors validated our approach, and several correlations between antibodies profiles and clinical parameters have been identified. In particular, we demonstrated that ratios between particular antibodies levels allow for accurate discrimination of patients according to their pathologic states.

Conclusion

Humoral response against hepatitis C virus linear epitopes is partly modified according to the disease state. This study highlights the importance of considering relative quantities of antibodies with different specificities rather than the amount of each antibody.

Electronic supplementary material

The online version of this article (doi: 10.1186/2193-1801-3-56) contains supplementary material, which is available to authorized users.

WITHDRAWN: Immunogenicity and safety of HCV E1E2 peptide vaccine in chronically HCV-infected patients who did not respond to interferon based therapy

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Role for IL-10 in inducing functional impairment of monocytes upon TLR4 ligation in patients with chronic HCV infections

The consequences of chronic infection with the HCV on immunity to distinct pathogens are not fully appreciated, despite the potent modulatory effects of HCV on the immune system. We observed that upon TLR4 ligation, monocytes from chronic HCV patients demonstrated three to five times lower TNF and IL-12p40 production as compared with healthy individuals. However, augmented production of TNF, IL-12p40, and IL-12p70 by monocytes was observed upon stimulation with R848. Importantly, we observed that the levels of IL-10 in chronic HCV patients are higher in serum and that more IL-10 is produced by monocytes as compared with healthy individuals. The inhibitory effect of IL-10 on the production of proinflammatory cytokines by monocytes was only observed upon LPS stimulation but not upon R848 stimulation, showing that only the TLR4 pathway in monocytes is sensitive to the suppressive effects of IL-10. Interestingly, monocytes stimulated with the TLR4 agonist, but not TLR8 agonist, produced higher levels of IL-10 when exposed to patient serum as compared with serum from healthy individuals. Our results indicate that by differentially affecting TLR4 and TLR8 pathways, IL-10 may mediate highly selective modulation of the function of monocytes observed in chronic HCV patients. This suggests that there is no overall increased susceptibility to pathogens but a specific suppression of the functionality of TLR4 signaling pathway in monocytes, which is, at least partly, mediated via IL-10.

Frequency of gC1qR+CD4+ T cells increases during acute hepatitis C virus infection and remains elevated in patients with chronic infection

CD4+ T cell responses are impaired in chronic HCV infection. To determine factor(s) involved in CD4+ T cell dysregulation, we examined the effect of extracellular core on the alteration of CD4+ T cell responses and the cell surface level of core-binding protein, gC1qR on CD4+ T cells from acute HCV patients with resolved and chronic infection. During the acute phase of infection, the frequency of gC1qR+CD4+ T cells increased in both resolved and chronic HCV infection compared to healthy controls. Notably, 6 months later, the frequency of gC1qR+CD4+ T cells maintained elevated in chronic patients compared to that in resolved patients. In addition, TCR stimulation increased the frequency of gC1qR+CD4+ T cells, resulting in core-induced inhibition of T cell responses in both resolved and chronic patients. These results suggest that HCV infection expands gC1qR+CD4+ T cells, which increase the susceptibility to core-mediated immune dysregulation and facilitate the establishment of HCV persistency.

Non-invasive, ultra-sensitive, high-throughput assays to quantify rare biomarkers in the blood

Many diseases are easier to treat and control when detected at an early stage of disease progression. Often, disease-related antigens or biomarkers are shed from the primary site and present in the blood. Unfortunately, there are very few tests capable of detecting these rare biomarkers in the blood. A blood test would be very useful to diagnose the disease earlier, monitor effectiveness of treatments, predict recurrence, and monitor recurrence. There is certainly a need to develop assays that are ultra-sensitive, non-invasive, and high-throughput. Here we describe several highly sensitive immunological assays we have developed to detect rare serum antigens. Initially we created an assay named immuno-detection amplified by T7 RNA polymerase (IDAT). To enhance the effectiveness and streamline the procedure, this assay was amended to the facile amplification system termed fluorescent amplification catalyzed by T7 polymerase technique (FACTT). These assays have been used to analyze the tumor antigen HER2 and the prion protein PrPSc. They can also be applied to other tumor markers or antigens from a variety of diseases such as cardiovascular disease, rheumatoid arthritis, Alzheimer's disease, Parkinson's disease, and hepatitis. These tests are not limited to testing only serum, but may also be applicable to detecting biomarkers in tissue, saliva, urine, cerebrospinal fluid, etc. Clearly, the FACTT-based technology represents an important step in the detection of rare molecules in fluids or tissues for a variety of diseases.

Establishment of hybrid cell lines producing monoclonal antibodies to a synthetic peptide from the E1 region of the hepatitis C virus

We aimed at establishing hybridoma cells secreting monoclonal antibodies (mAbs) against E1 synthetic peptide of HCV. BALB/c mice were immunized with HCV E1-synthetic peptide (GHRMAWDMM) and its spleenocytes were fused with the P3NS1 myeloma cell line. Two highly reactive and specific mAbs (10C7 IgG2b mAb, and 10B2 IgG1 mAb) were generated. The target HCV E1 antigen was identified at approximately 38 kDa in serum of infected individuals. A newly developed ELISA detected the target antigen in 90% of sera from HCV RNA infected individuals with a specificity of 84%. So, the generated mAbs may provide promising probes for serodiagnosis of HCV infection.