Hepatitis C virus E1 recruits high-density lipoprotein to support infectivity and evade antibody recognition.

Hepatitis C virus (HCV) is a member of the Flaviviridae family; however, unlike other family members, the HCV virion has an unusually high lipid content. HCV has two envelope glycoproteins, E1 and E2. E2 contributes to receptor binding, cell membrane attachment, and immune evasion. In contrast, the functions of E1 are poorly characterized due, in part, to challenges in producing the protein. This manuscript describes the expression and purification of a soluble E1 ectodomain (eE1) that is recognized by conformational, human monoclonal antibodies. eE1 forms a complex with apolipoproteins AI and AII, cholesterol, and phospholipids by recruiting high-density lipoprotein (HDL) from the extracellular media. We show that HDL binding is a function specific to eE1 and HDL hinders recognition of E1 by a neutralizing monoclonal antibody. Either low-density lipoprotein or HDL increases the production and infectivity of cell culture-produced HCV, but E1 preferentially selects HDL, influencing both viral life cycle and antibody evasion.IMPORTANCEHepatitis C virus (HCV) infection is a significant burden on human health, but vaccine candidates have yet to provide broad protection against this infection. We have developed a method to produce high quantities of soluble E1 or E2, the viral proteins located on the surface of HCV. HCV has an unusually high lipid content due to the recruitment of apolipoproteins. We found that E1 (and not E2) preferentially recruits host high-density lipoprotein (HDL) extracellularly. This recruitment of HDL by E1 prevents binding of E1 by a neutralizing antibody and furthermore prevents antibody-mediated neutralization of the virus. By comparison, low-density lipoprotein does not protect the virus from antibody-mediated neutralization. Our findings provide mechanistic insight into apolipoprotein recruitment, which may be critical for vaccine development.

Trans-ancestral fine-mapping of MHC reveals key amino acids associated with spontaneous clearance of hepatitis C in HLA-DQß1.

Spontaneous clearance of acute hepatitis C virus (HCV) infection is associated with single nucleotide polymorphisms (SNPs) on the MHC class II. We fine-mapped the MHC region in European (n = 1,600; 594 HCV clearance/1,006 HCV persistence) and African (n = 1,869; 340 HCV clearance/1,529 HCV persistence) ancestry individuals and evaluated HCV peptide binding affinity of classical alleles. In both populations, HLA-DQß1Leu26 (p valueMeta = 1.24 × 10-14) located in pocket 4 was negatively associated with HCV spontaneous clearance and HLA-DQß1Pro55 (p valueMeta = 8.23 × 10-11) located in the peptide binding region was positively associated, independently of HLA-DQß1Leu26. These two amino acids are not in linkage disequilibrium (r2 < 0.1) and explain the SNPs and classical allele associations represented by rs2647011, rs9274711, HLA-DQB1∗03:01, and HLA-DRB1∗01:01. Additionally, HCV persistence classical alleles tagged by HLA-DQß1Leu26 had fewer HCV binding epitopes and lower predicted binding affinities compared to clearance alleles (geometric mean of combined IC50 nM of persistence versus clearance; 2,321 nM versus 761.7 nM, p value = 1.35 × 10-38). In summary, MHC class II fine-mapping revealed key amino acids in HLA-DQß1 explaining allelic and SNP associations with HCV outcomes. This mechanistic advance in understanding of natural recovery and immunogenetics of HCV might set the stage for much needed enhancement and design of vaccine to promote spontaneous clearance of HCV infection.

Incidence of liver- and non-liver-related outcomes in patients with HCV-cirrhosis after SVR.

BACKGROUND & AIMS: As the long-term benefits of a sustained virological response (SVR) in HCV-related cirrhosis following direct-acting antiviral (DAA) treatment remain undefined, we assessed the incidence and predictors of liver-related events (LREs), non-liver-related events (NLREs) and mortality in DAA-treated patients with cirrhosis. METHODS: Consecutive patients with cirrhosis and SVR were enrolled in a longitudinal, single-center study, and divided into 3 cohorts: Cohort A (Child-Pugh A without a previous LRE), Cohort B (Child-Pugh B or Child-Pugh A with prior non-hepatocellular carcinoma [HCC] LREs), Cohort C (previous HCC). RESULTS: A total of 636 patients with cirrhosis (median 65 years-old, 58% males, 89% Child-Pugh A) were followed for 51 (8-68) months (Cohort A n = 480, Cohort B n = 89, Cohort C n = 67). The 5-year estimated cumulative incidences of LREs were 10.4% in Cohort A vs. 32.0% in Cohort B (HCC 7.7% vs. 19.7%; ascites 1.4% vs. 8.6%; variceal bleeding 1.3% vs. 7.8%; encephalopathy 0 vs. 2.5%) vs. 71% in Cohort C (HCC only) (p <0.0001). The corresponding figures for NLREs were 11.7% in Cohort A vs. 17.9% in Cohort B vs. 17.5% in Cohort C (p = 0.32). The 5-year estimated probabilities of liver-related vs. non-liver-related deaths were 0.5% vs. 4.5% in Cohort A, 16.2% vs. 8.8% in Cohort B and 12.1% vs. 7.7% in Cohort C. The all-cause mortality rate in Cohort A was similar to the rate expected for the general population stratified by age, sex and calendar year according to the Human Mortality Database, while it was significantly higher in Cohort B. CONCLUSIONS: Patients with cirrhosis and an SVR on DAAs face risks of liver-related and non-liver-related events and mortality; however, their incidence is strongly influenced by pre-DAA patient history. LAY SUMMARY: In this large single-center study enrolling patients with hepatitis C virus (HCV)-related cirrhosis cured by direct-acting antivirals, pre-treatment liver disease history strongly influenced long-term outcomes. In patients with HCV-related cirrhosis, hepatocellular carcinoma was the most frequent liver-related complication after viral cure. Due to improved long-term outcomes, patients with cirrhosis after HCV cure are exposed to a significant proportion of non-liver-related events.

Viral hepatitis amidst COVID-19 in Africa: Implications and recommendations.

Hepatitis, a significant cause of mortality worldwide, results in around 1.34 million deaths each year globally. Africa is not exempt from the plague of Hepatitis. Around 100 million estimated individuals are infected with Hepatitis B or C. Egypt has the highest prevalence of cases of Hepatitis followed by Cameroon and Burundi. The continent is severely affected by the onset of the COVID-19 pandemic, as the virus has added an additional burden on the already fragile continent. With the pandemic, it is presumable that Hepatitis like other viral diseases will pose a threat to collapsing healthcare system. Therefore, for Africa to become more resilient in the face of such menaces, including Hepatitis, further prevention policies are required to be implemented.

MicroRNA let-7b inhibits hepatitis C virus and induces apoptosis in human hepatoma cells.

BACKGROUND: Small non-coding RNAs have emerged as essential modulators of viral infections such as hepatitis C virus (HCV). Cellular miRNAs directly regulate the viral infectivity and indirectly by targeting virus-host factors. The current study investigates the inhibitory effect of let-7b miRNA on HCV replication in the Hepatocarcinoma cell line (Huh7.5). METHODS AND RESULTS: The algorithm-based search revealed that let-7b, a high score microRNA, has target sequences on the HCV genome. The Huh7.5 cells were stably transduced with let-7b lentiviral vectors (Huh7.5/let-7b) and mock (Huh7.5/scrambled). The expression of the let-7b level was assessed by real-time PCR assay and Red fluorescence microscope. A dual-luciferase assay was conducted to evaluate the liver-specific let-7b and HCV genome interaction. In the next step, for establishing HCVcc, Full-length HCV-RNA was transduced to naïve Huh7.5, Huh7.5/scrambled, and Huh7.5/let-7b cells. The results of in silico analysis and dual-luciferase reporter assay exhibited a specific interaction of HCV-NS5B and let-7b. Real-time PCR analysis revealed that in contrast to infected naïve Huh7.5 cells and Huh7.5/scrambled, a significant decrease in HCV-RNA load was seen in Huh7.5/let-7b cells. On the other hand, the Flow Cytometry test showed that let-7b could significantly induce the apoptosis pathway in Huh7.5/let-7b. CONCLUSIONS: The results also suggest that let-7b, as a target of the HCV genome, potentially reduces HCV replication and raises cell apoptosis rate. We suggest that let-7b directly downregulates HCV replication and may serve as a unique antiviral therapy.

Peripheral blood iNKT cell activation correlates with liver damage during acute hepatitis C.

Invariant NK T (iNKT) cells are implicated in viral clearance; however, their role in hepatitis C virus (HCV) infection remains controversial. Here, iNKT cells were studied during different stages of HCV infection. iNKT cells from patients with acute HCV infection and people who inject drugs (PWID) with chronic or spontaneously resolved HCV infection were characterized by flow cytometry. In a longitudinal analysis during acute HCV infection, frequencies of activated CD38+ iNKT cells reproducibly declined in spontaneously resolving patients, whereas they were persistently elevated in patients progressing to chronic infection. During the first year of infection, the frequency of activated CD38+ or CD69+ iNKT cells strongly correlated with alanine transaminase levels with particularly pronounced correlations in spontaneously resolving patients. Increased frequencies of activated iNKT cells in chronic HCV infection were confirmed in cross-sectional analyses of PWID with chronic or spontaneously resolved HCV infection; however, no apparent functional differences were observed with various stimulation protocols. Our data suggest that iNKT cells are activated during acute hepatitis C and that activation is sustained in chronic infection. The correlation between the frequency of activated iNKT cells and alanine transaminase may point toward a role of iNKT cells in liver damage.

HCV-related lymphoproliferative disorders in the direct-acting antiviral era: From mixed cryoglobulinaemia to B-cell lymphoma.

HCV has been shown to induce many B-cell lymphoproliferative disorders. B lymphocytes specialise in producing immunoglobulins and, during chronic HCV infection, they can cause manifestations ranging from polyclonal hypergammaglobulinaemia without clinical repercussions, through mixed cryoglobulinaemic vasculitis to B-cell non-Hodgkin lymphoma. This spectrum is supported by substantial epidemiological, pathophysiological and therapeutic data. Many, although not all, of the pathogenic pathways leading from one extreme to another have been decrypted. Chronic viral antigen stimulation of B lymphocytes has a central role until the final steps before overt malignancy. This has direct implications for treatment strategies, which always include the use of direct-acting antivirals sometimes alongside immunosuppressants. The role of direct-acting antivirals has been well established in patients with cryoglobulinaemia vasculitis. However, their positive impact on B-cell non-Hodgkin lymphoma needs to be confirmed in larger studies with longer follow-up.

Hepatitis C: Diagnosis and Management.

Screening recommendations and treatment guidelines for hepatitis C virus (HCV) infection have been updated. People at the greatest risk of HCV infection are those between 18 and 39 years of age and those who use injection drugs. Universal screening with an anti-HCV antibody test with follow-up reflex HCV RNA polymerase chain reaction testing for positive results to confirm active disease is recommended at least once for all adults 18 years and older and during each pregnancy. Any person with ongoing risk factors should be screened periodically as long as the at-risk behavior persists. One-time screening is recommended for patients younger than 18 years with risk factors. For treatment-naive adults without cirrhosis or with compensated cirrhosis, a simplified treatment regimen consisting of eight weeks of glecaprevir/pibrentasvir or 12 weeks of sofosbuvir/velpatasvir results in greater than 95% cure rates. Undetectable HCV RNA 12 weeks after completing therapy is considered a virologic cure (i.e., sustained virologic response). A sustained virologic response is associated with lower all-cause mortality and improves hepatic and extrahepatic manifestations, cognitive function, physical health, work productivity, and quality of life. In patients with compensated cirrhosis, posttreatment surveillance for hepatocellular carcinoma and esophageal varices should include abdominal ultrasonography (with or without alpha fetoprotein) every six months and upper endoscopy every two to three years. In the absence of cirrhosis, no liver-related follow-up is recommended.

The Bank Vole (Clethrionomys glareolus)-Small Animal Model for Hepacivirus Infection.

Many people worldwide suffer from hepatitis C virus (HCV) infection, which is frequently persistent. The lack of efficient vaccines against HCV and the unavailability of or limited compliance with existing antiviral therapies is problematic for health care systems worldwide. Improved small animal models would support further hepacivirus research, including development of vaccines and novel antivirals. The recent discovery of several mammalian hepaciviruses may facilitate such research. In this study, we demonstrated that bank voles (Clethrionomys glareolus) were susceptible to bank vole-associated Hepacivirus F and Hepacivirus J strains, based on the detection of hepaciviral RNA in 52 of 55 experimentally inoculated voles. In contrast, interferon α/ß receptor deficient C57/Bl6 mice were resistant to infection with both bank vole hepaciviruses (BvHVs). The highest viral genome loads in infected voles were detected in the liver, and viral RNA was visualized by in situ hybridization in hepatocytes, confirming a marked hepatotropism. Furthermore, liver lesions in infected voles resembled those of HCV infection in humans. In conclusion, infection with both BvHVs in their natural hosts shares striking similarities to HCV infection in humans and may represent promising small animal models for this important human disease.

A Prospective Observational Study of 42 Patients with COVID-19 infection and a History of Hepatitis C Virus Infection and Thyroid Disease with Follow-Up Thyroid Function and Autoantibody Testing.

BACKGROUND Thyroiditis is an important extrahepatic association in chronic hepatitis C virus (HCV) infection. There have been reports of an association between SARS-CoV-2 infection and the onset or re-activation of autoimmune hypothyroidism. Therefore, we performed this prospective observational study of 42 patients with COVID-19 infection and a history of hepatitis C virus infection and thyroid disease with follow-up thyroid function and autoantibody testing. MATERIAL AND METHODS From April 2020 to October 2020, we performed a prospective observational study of patients with cured hepatitis C virus (HCV) infection and documented thyroid disease who became infected with SARS-CoV-2 (confirmed by SARS-CoV-2 RNA detection via reverse-transcription polymerase chain reaction [RT-PCT] from the upper respiratory tract, both nasal and pharyngeal swabs). Evaluation at 1 and 3 months after SARS-CoV-2 infection included serum determination of antithyroid antibodies (anti-thyroglobulin [anti-Tg] and antithyroid peroxidase [ATPO]), thyroid-stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), and evaluation of thyroid medication, with dose adjustment if required. RESULTS One-month follow-up showed that both patients with autoimmune thyroiditis as well as patients without antibodies had increased ATPO levels. Also, levels of TSH, fT3, and fT4 were significantly decreased. At 3-month follow-up, levels of ATPO were decreased in all patient groups and the levels of thyroid hormones increased to normal values. CONCLUSIONS This study supports previous reports of an association between SARS-CoV-2 infection and thyroid dysfunction associated with thyroid autoantibodies. Thyroid function tests may be considered as part of the laboratory work-up in patients with COVID-19.

Hepatitis C-associated late-onset schizophrenia: a nationwide, population-based cohort study.

BACKGROUND: Whether infection with the hepatitis C virus (HCV) causes schizophrenia - and whether the associated risk reverses after anti-HCV therapy - is unknown; we aimed to investigate these topics. METHODS: We conducted a nationwide, population-based cohort study using the Taiwan National Health Insurance Research Database (TNHIRD). A diagnosis of schizophrenia was based on criteria from the International Classification of Diseases, 9th revision (295.xx). RESULTS: From 2003 to 2012, from a total population of 19 298 735, we enrolled 3 propensity-score-matched cohorts (1:2:2): HCV-treated (8931 HCV-infected patients who had received interferon-based therapy for ≥ 6 months); HCV-untreated (17 862); and HCV-uninfected (17 862) from the TNHIRD. Of the total sample (44 655), 82.81% (36 980) were 40 years of age or older. Of the 3 cohorts, the HCV-untreated group had the highest 9-year cumulative incidence of schizophrenia (0.870%, 95% confidence interval [CI] 0.556%-1.311%; p < 0.001); the HCV-treated (0.251%, 95% CI 0.091%-0.599%) and HCV-uninfected (0.118%, 95% CI 0.062%-0.213%) cohorts showed similar cumulative incidence of schizophrenia (p = 0.33). Multivariate Cox analyses showed that HCV positivity (hazard ratio [HR] 3.469, 95% CI 2.168-5.551) was independently associated with the development of schizophrenia. The HCV-untreated cohort also had the highest cumulative incidence of overall mortality (20.799%, 95% CI 18.739%-22.936%; p < 0.001); the HCV-treated (12.518%, 95% CI 8.707%-17.052%) and HCV uninfected (6.707%, 95% CI 5.533%-8.026%) cohorts showed similar cumulative incidence of mortality (p = 0.12). LIMITATIONS: We were unable to determine the precise mechanism of the increased risk of schizophrenia in patients with HCV infection. CONCLUSION: In a population-based cohort (most aged ≥ 40 years), HCV positivity was a potential risk factor for the development of schizophrenia; the HCV-associated risk of schizophrenia might be reversed by interferon-based antiviral therapy.

A Review on Extrahepatic Manifestations of Chronic Hepatitis C Virus Infection and the Impact of Direct-Acting Antiviral Therapy.

Extrahepatic manifestations are a feature of chronic hepatitis C virus (HCV) infection. In the course of chronic HCV infection, about 70% of patients have one or more extrahepatic manifestations. The latter are often the first and only clinical sign of infection. Experimental and clinical data support a causal association for many extrahepatic manifestations and HCV infection, which include mixed cryoglobulinemia, non-Hodgkin lymphomas (NHL), cardiovascular disease, insulin resistance, type 2 diabetes, neurological and psychiatric disease and other rheumatic diseases. All these extrahepatic conditions influence the morbidity, quality of life and mortality of HCV-infected patients. Currently, interferon-free therapeutic regimens with direct-acting antiviral agents (DAA) offer the possibility of treatment to almost the entire infected population, irrespective of stage of cirrhosis and associated serious comorbidities, always maintaining a high efficacy and tolerability. Several studies have shown a close association between HCV clearance by DAAs and an improvement or reduction in the risk of extrahepatic manifestations. Patients with HCV after a sustained virologic response (SVR) by DAA treatment have a lower risk than non-responders of developing cryoglobulinemic vasculitis and B-cell non-Hodgkin's lymphomas. Furthermore, the SVR by DAA also reduces the risk of acute coronary syndrome, cardiovascular disease, insulin resistance and type 2 diabetes, and it improves atherosclerosis. HCV clearance by DAA also improves the quality of life and survival of patients with chronic HCV infection with associated extrahepatic diseases. Thus, DAAs should be initiated as early as possible in HCV patients with extrahepatic manifestations.

Role of Serum Vitamin D, Interleukin 13, and microRNA-135a in Hepatocellular Carcinoma and Treatment Failure in Egyptian HCV-Infected Patients Receiving Direct Antiviral Agents.

Direct-acting antivirals (DAAs) are used for hepatitis C virus (HCV) treatment. However, treatment failure and hepatocellular carcinoma (HCC) development following treatment was reported. In this study, we assessed the role of serum vitamin D, interleukin 13 (IL-13), and microRNA-135a in the prediction of treatment failure with DAA and HCC development among Egyptian HCV-infected patients. A total of 950 patients with HCV-related chronic liver disease underwent DAA treatment. Before DAAs, serum vitamin D and IL-13 were determined by ELISA, and gene expression of miRNA-135a was assessed in serum by real-time PCR. The predictive abilities of these markers were determined using the receiver operating characteristic (ROC) curve. Sustained virological response (SVR) was achieved in 92.6% of HCV-infected patients (responders). High viral load, IL-13, miRNA-135a, and low vitamin D levels were associated with treatment failure and HCC development. HCC development was recorded in non-responders, but not in the responders (35.7% vs. 0% p < 0.001). In conclusion: serum IL-13, Vitamin D, and miRNA-135a could be potential biomarkers in monitoring DAA treatment and HCC prediction. DAAs-induced SVR may decrease the incidence of HCC.

The Role of RASs /RVs in the Current Management of HCV.

The approval of combination therapies with direct-acting antiviral (DAA) regimens has led to significant progress in the field of hepatitis C virus (HCV) treatment. Although most patients treated with these agents achieve a virological cure, resistance to DAAs is a major issue. The rapid emergence of resistance-associated substitutions (RASs), in particular in the context of incomplete drug pressure, has an impact on sustained virological response (SVR) rates. Several RASs in NS3, NS5A and NS5B have been linked with reduced susceptibility to DAAs. RAS vary based on HCV characteristics and the different drug classes. DAA-resistant HCV variant haplotypes (RVs) are dominant in cases of virological failure. Viruses with resistance to NS3-4A protease inhibitors are only detected in the peripheral blood in a time frame ranging from weeks to months following completion of treatment, whereas NS5A inhibitor-resistant viruses may persist for years. Novel agents have been developed that demonstrate promising results in DAA-experienced patients. The recent approval of broad-spectrum drug combinations with a high genetic barrier to resistance and antiviral potency may overcome the problem of resistance.

Viral proteins recognized by different TLRs.

Virus invasion activates the host's innate immune response, inducing the production of numerous cytokines and interferons to eliminate pathogens. Except for viral DNA/RNA, viral proteins are also targets of pattern recognition receptors. Membrane-bound receptors such as Toll-like receptor (TLR)1, TLR2, TLR4, TLR6, and TLR10 relate to the recognition of viral proteins. Distinct TLRs perform both protective and detrimental roles for a specific virus. Here, we review viral proteins serving as pathogen-associated molecular patterns and their corresponding TLRs. These viruses are all enveloped, including respiratory syncytial virus, hepatitis C virus, measles virus, herpesvirus human immunodeficiency virus, and coronavirus, and can encode proteins to activate innate immunity in a TLR-dependent way. The TLR-viral protein relationship plays an important role in innate immunity activation. A detailed understanding of their pathways contributes to a novel direction for vaccine development.

Cellular OCIAD2 protein is a proviral factor for hepatitis C virus replication.

Hepatitis C virus (HCV) nonstructural protein NS4B is necessary for HCV replication. Our previous research found that NS4B-associated cellular proteins PREB and Surfeit 4 are involved in HCV replication. However, the molecular mechanism of HCV replication is not fully understood. Here we identified cellular ovarian cancer immunoreactive antigen domain containing 2 (OCIAD2) protein as a novel NS4B-associated HCV host cofactor by screening with small interfering RNA. Knockdown of OCIAD2 reduced significantly the HCV replication in a dose-dependent and genotype-independent manner. Further research showed that OCIAD2 was recruited into the HCV RNA replication complex by the interaction with NS4B. Interestingly, HCV replication induced OCIAD2 expression. In turn, overexpression of wild OCIAD2 also promoted virus replication whereas that of OCIAD2 mutant lacking the ability to bind NS4B exerted no effect on HCV replication. We also examined whether OCIAD2 interacted with other proteins participating in the HCV RNA replication complex including viral proteins NS5A, NS5B, and cellular proteins PREB, Surfeit 4. The results showed that OCIAD2 interacted with PREB and NS5A, but not NS5B or Surfeit 4. Our findings provide new insights into the function of OCIAD2 and HCV replication mechanism.

Hepatitis C Virus Infection in Persons Who Inject Drugs in the Middle East and North Africa: Intervention Strategies.

There is a high incidence and prevalence of hepatitis C viral infection in persons with or without substance use disorders (SUDs) in the Middle East and North Africa (MENA) region, but only a small number receive comprehensive care. Highly effective direct-acting antiviral (DAA) medications are available at substantially lower costs; however, complete elimination of the hepatitis C virus (HCV) can only be achieved if integrated care strategies target those at highest risk for HCV infection and transmission and improve access to care. Due to the high prevalence of SUD in the MENA region, strategies to eliminate HCV must focus on integrated healthcare across multiple subspecialties, including addiction medicine, psychiatry, infectious diseases, hepatology, and social work. In this invited manuscript, we review the epidemiology of HCV in the MENA region and highlight intervention strategies to attain the WHO's goal of HCV eradication by 2030.

Where to Next? Research Directions after the First Hepatitis C Vaccine Efficacy Trial.

Thirty years after its discovery, the hepatitis C virus (HCV) remains a leading cause of liver disease worldwide. Given that many countries continue to experience high rates of transmission despite the availability of potent antiviral therapies, an effective vaccine is seen as critical for the elimination of HCV. The recent failure of the first vaccine efficacy trial for the prevention of chronic HCV confirmed suspicions that this virus will be a challenging vaccine target. Here, we examine the published data from this first efficacy trial along with the earlier clinical and pre-clinical studies of the vaccine candidate and then discuss three key research directions expected to be important in ongoing and future HCV vaccine development. These include the following: 1. design of novel immunogens that generate immune responses to genetically diverse HCV genotypes and subtypes, 2. strategies to elicit broadly neutralizing antibodies against envelope glycoproteins in addition to cytotoxic and helper T cell responses, and 3. consideration of the unique immunological status of individuals most at risk for HCV infection, including those who inject drugs, in vaccine platform development and early immunogenicity trials.

Protocol: Prospective observational study aiming for micro-elimination of hepatitis C virus in Nagawa town: The Nagawa Project.

BACKGROUND: The World Health Organization has set a goal of hepatitis C virus (HCV) elimination by the year 2030. However, no regions in Japan have succeeded in eradicating HCV. Micro-elimination is an approach to attain hepatitis C eradication in which national eradication goals are applied to specific populations so that viral treatment and control efforts can move forward quickly and efficiently. In order to eradicate HCV from Japan, this study aims to achieve HCV micro-elimination in the town of Nagawa. METHODS AND DESIGN: The Nagawa Project is an ongoing, prospective, multiple-institution, observational study running from April 1, 2021, to March 31, 2024. All residents of Nagawa town, excluding those under 20 years of age, not consenting to the study, or unable to undergo health check-ups due to nursing care needs, will be included. If found to be HCV antibody-positive, the participant will be recommended to see a doctor in consideration of MAC-2 binding protein glycosylation isomer values. Then, the participant will undergo serum HCV RNA measurement with the real-time polymerase chain reaction by an attending physician. If the participant is HCV RNA-positive, he or she will be referred to a hepatologist for further evaluation. In the case of a definitive diagnosis of chronic hepatitis C, direct acting antiviral treatment will be initiated. Through this process, HCV will be systematically micro-eliminated from the region. DISCUSSION: The Nagawa Project will reveal the prevalence of chronic HCV in addition to the HCV eradication rate in Nagawa town towards achieving HCV micro-elimination. TRIAL REGISTRATION: This study is performed by Shinshu University School of Medicine and was registered as UMIN 000044114 on May 6, 2021.

Characterization of linear epitope specificity of antibodies potentially contributing to spontaneous clearance of hepatitis C virus.

BACKGROUND: Around 30% of the HCV infected patients can spontaneously clear the virus. Cumulative evidence suggests the role of neutralizing antibodies in such spontaneous resolution. Understanding the epitope specificity of such antibodies will inform the rational vaccine design as such information is limited to date. In addition to conformational epitope targeted antibodies, linear epitope specific antibodies have been identified that are broadly cross reactive against diverse HCV strains. In this study, we have characterized the potential role of three conserved linear epitopes in the spontaneous clearance of HCV. METHODS: We tested the reactivity of sera from chronic patients (CP) and spontaneous resolvers (SR) with linear peptides corresponding to three conserved regions of HCV envelope protein E2 spanning amino acids 412-423, 523-532 and 432-443 using ELISA. Subsequently, we characterized the dependency of HCV neutralization by the reactive serum samples on the antibodies specific for these epitopes using pseudoparticle-based neutralization assay. In ELISA most of the CP sera showed reactivity to multiple peptides while most of the SR samples were reactive to a single peptide suggesting presence of more specific antibodies in the SR sera. In most of the HCVpp neutralizing sera of particular peptide reactivity the neutralization was significantly affected by the presence of respective peptide. HCV neutralization by CP sera was affected by multiple peptides while 75% of the HCVpp neutralizing SR sera were competed by the 432 epitope. CONCLUSIONS: These findings suggest that individuals who spontaneously resolve HCV infection at the acute phase, can produce antibodies specific for conserved linear epitopes, and those antibodies can potentially play a role in the spontaneous viral clearance. The epitope present in the 432-443 region of E2 was identified as the primary neutralizing epitope with potential role in spontaneous viral clearance and this epitope potentiates for the design of immunogen for prophylactic vaccine.