Neutralizing antibodies evolve to exploit vulnerable sites in the HCV envelope glycoprotein E2 and mediate spontaneous clearance of infection.

Individuals who clear primary hepatitis C virus (HCV) infections clear subsequent reinfections more than 80% of the time, but the mechanisms are poorly defined. Here, we used HCV variants and plasma from individuals with repeated clearance to characterize longitudinal changes in envelope glycoprotein E2 sequences, function, and neutralizing antibody (NAb) resistance. Clearance of infection was associated with early selection of viruses with NAb resistance substitutions that also reduced E2 binding to CD81, the primary HCV receptor. Later, peri-clearance plasma samples regained neutralizing capacity against these variants. We identified a subset of broadly NAbs (bNAbs) for which these loss-of-fitness substitutions conferred resistance to unmutated bNAb ancestors but increased sensitivity to mature bNAbs. These data demonstrate a mechanism by which neutralizing antibodies contribute to repeated immune-mediated HCV clearance, identifying specific bNAbs that exploit fundamental vulnerabilities in E2. The induction of bNAbs with these specificities should be a goal of HCV vaccine development.

Analysis of antibodies from HCV elite neutralizers identifies genetic determinants of broad neutralization.

The high genetic diversity of hepatitis C virus (HCV) complicates effective vaccine development. We screened a cohort of 435 HCV-infected individuals and found that 2%-5% demonstrated outstanding HCV-neutralizing activity. From four of these patients, we isolated 310 HCV antibodies, including neutralizing antibodies with exceptional breadth and potency. High neutralizing activity was enabled by the use of the VH1-69 heavy-chain gene segment, somatic mutations within CDRH1, and CDRH2 hydrophobicity. Structural and mutational analyses revealed an important role for mutations replacing the serines at positions 30 and 31, as well as the presence of neutral and hydrophobic residues at the tip of the CDRH3. Based on these characteristics, we computationally created a de novo antibody with a fully synthetic VH1-69 heavy chain that efficiently neutralized multiple HCV genotypes. Our findings provide a deep understanding of the generation of broadly HCV-neutralizing antibodies that can guide the design of effective vaccine candidates.

Polyvalent immunization elicits a synergistic broadly neutralizing immune response to hypervariable region 1 variants of hepatitis C virus.

A hepatitis C virus (HCV) vaccine is urgently needed. Vaccine development has been hindered by HCV's genetic diversity, particularly within the immunodominant hypervariable region 1 (HVR1). Here, we developed a strategy to elicit broadly neutralizing antibodies to HVR1, which had previously been considered infeasible. We first applied a unique information theory-based measure of genetic distance to evaluate phenotypic relatedness between HVR1 variants. These distances were used to model the structure of HVR1's sequence space, which was found to have five major clusters. Variants from each cluster were used to immunize mice individually, and as a pentavalent mixture. Sera obtained following immunization neutralized every variant in a diverse HCVpp panel (n = 10), including those resistant to monovalent immunization, and at higher mean titers (1/ID50 = 435) than a glycoprotein E2 (1/ID50 = 205) vaccine. This synergistic immune response offers a unique approach to overcoming antigenic variability and may be applicable to other highly mutable viruses.

Hepatitis C virus modified sE2F442NYT as an antigen in candidate vaccine facilitates human immune cell activation.

The rational selection of hepatitis C virus (HCV) vaccine antigen will aid in the prevention of future chronic liver disease burden and associated healthcare costs. We have previously shown that HCV E2 glycoprotein is not highly immunogenic, and the modification of E2 reduced CD81 binding and displayed altered cytokine and protective immune responses in vitro and in a surrogate mouse model. Here, we compared the influence of a parental and a modified sE2F442NYT glycoprotein region from HCV genotype 1a for the activation of peripheral blood mononuclear cell (PBMC)-derived dendritic cells (DCs), CD4+T cells, and B cells. Modified sE2F442NYT, when incubated with DCs, induced a higher number of CD86-positive cells. The sE2F442NYT or parental sE2 encapsulated as mRNA-lipid nanoparticle (sE2F442NYT mRNA-LNP) primed DCs co-cultured with autologous CD4+T cells did not induce CD25 or forkhead box P3 expression. PBMC-derived CD4+T cells treated with sE2F442NYT exhibited enhanced signal transducer and activator of transcription (Stat)1/Stat4 phosphorylation in response to anti-CD3/CD28 stimulation in comparison to parental sE2 treatment and facilitated isotype switching in B cells, leading to the generation of a broader subclass of antibodies. Cells treated with modified sE2F442NYT displayed an increase in activated Stat3 and extracellular signal-regulated kinase (ERK). Likewise, PBMC-derived naïve B cells upon in vitro stimulation with sE2F442NYT induced an increased proliferation, Stat3 and ERK activation, and protein kinase B (Akt) suppression. Thus, the modified sE2F442NYT antigen from HCV facilitates improved DC, CD4+T, and B cell activation compared to parental sE2 to better induce a robust protective immune response, supporting its selection as an HCV candidate vaccine antigen for preclinical and clinical HCV vaccine trials.IMPORTANCEThe nature of an enhanced immune response induced by sE2F442NYT will help in the selection of a broad cross-protective antigen from hepatitis C virus genotypes, and the inclusion of relatively conserved sE1 with sE2F442NYT may further strengthen the efficacy of the candidate vaccine in evaluating it for human use.

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.

Induction of broadly neutralizing antibodies using a secreted form of the hepatitis C virus E1E2 heterodimer as a vaccine candidate.

SignificanceHepatitis C virus chronically infects approximately 1% of the world's population, making an effective vaccine for hepatitis C virus a major unmet public health need. The membrane-associated E1E2 envelope glycoprotein has been used in clinical studies as a vaccine candidate. However, limited neutralization breadth and difficulty in producing large amounts of homogeneous membrane-associated E1E2 have hampered efforts to develop an E1E2-based vaccine. Our previous work described the design and biochemical validation of a native-like soluble secreted form of E1E2 (sE1E2). Here, we describe the immunogenic characterization of the sE1E2 complex. sE1E2 elicited broadly neutralizing antibodies in immunized mice, with increased neutralization breadth relative to the membrane-associated E1E2, thereby validating this platform as a promising model system for vaccine development.

Advancing Diagnosis of Current Hepatitis C Virus Infection: A Key to Hepatitis C Elimination in the United States.

More than 2 million adults have hepatitis C virus (HCV) infection in the United States, and new infections continue to increase. Without treatment, HCV infection can lead to advanced liver disease and death. Treatment is recommended for nearly everyone with hepatitis C, resulting in a cure in >95% of people treated and raising the possibility of hepatitis C elimination. Testing is the first step to accessing life-saving treatment. The Centers for Disease Control and Prevention recommends hepatitis C screening for all adults, all pregnant persons, and anyone with risk; yet about one-third of people with hepatitis C remain unaware of their infection. Testing begins with a hepatitis C antibody test, followed, when reactive, by a nucleic acid test to detect HCV RNA. This antibody-first, 2-step testing strategy misses early infections and can result in incomplete diagnoses. Advancements in hepatitis C diagnostics and the US regulatory landscape have created an opportunity to include viral-first testing strategies and improve hepatitis C diagnosis. This journal supplement features 8 articles detailing challenges and opportunities for improving hepatitis C diagnostics in support of advancing hepatitis C elimination in the United States.

Randomized Trial of a Vaccine Regimen to Prevent Chronic HCV Infection.

BACKGROUND: A safe and effective vaccine to prevent chronic hepatitis C virus (HCV) infection is a critical component of efforts to eliminate the disease. METHODS: In this phase 1-2 randomized, double-blind, placebo-controlled trial, we evaluated a recombinant chimpanzee adenovirus 3 vector priming vaccination followed by a recombinant modified vaccinia Ankara boost; both vaccines encode HCV nonstructural proteins. Adults who were considered to be at risk for HCV infection on the basis of a history of recent injection drug use were randomly assigned (in a 1:1 ratio) to receive vaccine or placebo on days 0 and 56. Vaccine-related serious adverse events, severe local or systemic adverse events, and laboratory adverse events were the primary safety end points. The primary efficacy end point was chronic HCV infection, defined as persistent viremia for 6 months. RESULTS: A total of 548 participants underwent randomization, with 274 assigned to each group. There was no significant difference in the incidence of chronic HCV infection between the groups. In the per-protocol population, chronic HCV infection developed in 14 participants in each group (hazard ratio [vaccine vs. placebo], 1.53; 95% confidence interval [CI], 0.66 to 3.55; vaccine efficacy, -53%; 95% CI, -255 to 34). In the modified intention-to-treat population, chronic HCV infection developed in 19 participants in the vaccine group and 17 in placebo group (hazard ratio, 1.66; 95% CI, 0.79 to 3.50; vaccine efficacy, -66%; 95% CI, -250 to 21). The geometric mean peak HCV RNA level after infection differed between the vaccine group and the placebo group (152.51×103 IU per milliliter and 1804.93×103 IU per milliliter, respectively). T-cell responses to HCV were detected in 78% of the participants in the vaccine group. The percentages of participants with serious adverse events were similar in the two groups. CONCLUSIONS: In this trial, the HCV vaccine regimen did not cause serious adverse events, produced HCV-specific T-cell responses, and lowered the peak HCV RNA level, but it did not prevent chronic HCV infection. (Funded by the National Institute of Allergy and Infectious Diseases; ClinicalTrials.gov number, NCT01436357.).

B cell overexpression of FCRL5 and PD-1 is associated with low antibody titers in HCV infection.

Antibodies targeting the hepatitis C virus (HCV) envelope glycoprotein E2 are associated with delayed disease progression, and these antibodies can also facilitate spontaneous clearance of infection in some individuals. However, many infected people demonstrate low titer and delayed anti-E2 antibody responses. Since a goal of HCV vaccine development is induction of high titers of anti-E2 antibodies, it is important to define the mechanisms underlying these suboptimal antibody responses. By staining lymphocytes with a cocktail of soluble E2 (sE2) glycoproteins, we detected HCV E2-specific (sE2+) B cells directly ex vivo at multiple acute infection timepoints in 29 HCV-infected subjects with a wide range of anti-E2 IgG titers, including 17 persistently infected subjects and 12 subjects with spontaneous clearance of infection. We performed multi-dimensional flow cytometric analysis of sE2+ and E2-nonspecific (sE2-) class-switched B cells (csBC). In sE2+ csBC from both persistence and clearance subjects, frequencies of resting memory B cells (rMBC) were reduced, frequencies of activated MBC (actMBC) and tissue-like MBC (tlMBC) were increased, and expression of FCRL5, an IgG receptor, was significantly upregulated. Across all subjects, plasma anti-E2 IgG levels were positively correlated with frequencies of sE2+ rMBC and sE2+ actMBC, while anti-E2 IgG levels were negatively correlated with levels of FCRL5 expression on sE2+ rMBC and PD-1 expression on sE2+ actMBC. Upregulation of FCRL5 on sE2+ rMBC and upregulation of PD-1 on sE2+ actMBC may limit anti-E2 antibody production in vivo. Strategies that limit upregulation of these molecules could potentially generate higher titers of protective antibodies against HCV or other pathogens.

Differential immune transcriptomic profiles between vaccinated and resolved HCV reinfected subjects.

Successive episodes of hepatitis C virus (HCV) infection represent a unique natural rechallenge experiment to define correlates of long-term protective immunity and inform vaccine development. We applied a systems immunology approach to characterize longitudinal changes in the peripheral blood transcriptomic signatures in eight subjects who spontaneously resolved two successive HCV infections. Furthermore, we compared these signatures with those induced by an HCV T cell-based vaccine regimen. We identified a plasma cell transcriptomic signature during early acute HCV reinfection. This signature was absent in primary infection and following HCV vaccine boost. Spontaneous resolution of HCV reinfection was associated with rapid expansion of glycoprotein E2-specifc memory B cells in three subjects and transient increase in E2-specific neutralizing antibodies in six subjects. Concurrently, there was an increase in the breadth and magnitude of HCV-specific T cells in 7 out of 8 subjects. These results suggest a cooperative role for both antibodies and T cells in clearance of HCV reinfection and support the development of next generation HCV vaccines targeting these two arms of the immune system.

Validation of dried blood spots for capturing hepatitis C virus diversity for genomic surveillance.

Dried blood spots (DBS) have emerged as a promising alternative to traditional venous blood for hepatitis C virus (HCV) testing. However, their capacity to accurately reflect the genetic diversity of HCV remains poorly understood. We employed deep sequencing and advanced phylogenetic analyses on paired plasma and DBS samples from two common subtypes to evaluate the suitability of DBS for genomic surveillance. Results demonstrated that DBS captured equivalent viral diversity compared to plasma with no phylogenetic discordance observed. The ability of DBS to accurately reflect the profile of viral genetic diversity suggests it may be a promising avenue for future surveillance efforts to curb HCV outbreaks.

High prevalence of hepatitis C virus infection among incarcerated persons: Results from the Louisiana Hepatitis C Elimination Plan's opt-out testing program in prisons.

In the United States, modelling studies suggest a high prevalence of hepatitis C virus (HCV) infection in incarcerated populations. However, limited HCV testing has been conducted in prisons. Through the Louisiana Hepatitis C Elimination Plan, persons incarcerated in the eight state prisons were offered HCV testing from 20 September 2019 to 14 July 2022, and facility entry/exit HCV testing was introduced. Multivariable logistic regression was used to evaluate associations with HCV antibody (anti-HCV) positivity and viremia. Of 17,231 persons in the eight state prisons screened for anti-HCV, 95.1% were male, 66.7% were 30-57 years old, 3% were living with HIV, 68.2% were Black and 2904 (16.9%) were anti-HCV positive. HCV RNA was detected in 69.3% of anti-HCV positive individuals tested. In the multivariable model, anti-HCV positivity was associated with older age including those 30-57 (odds ratio [OR] 3.53, 95% confidence interval [CI] 2.96-4.20) and those ≥58 (OR 10.43, 95% CI 8.66-12.55) as compared to those ≤29 years of age, living with HIV (OR 1.68, 95% CI 1.36-2.07), hepatitis B (OR 1.83, 95% CI 1.25-2.69) and syphilis (OR 1.51, 95% CI 1.23-1.86). HCV viremia was associated with male sex (OR 1.89, 95% CI 1.36-2.63) and Black race (OR 1.42, 95% CI 1.20-1.68). HCV prevalence was high in the state prisons in Louisiana compared to community estimates. To the extent that Louisiana is representative, to eliminate HCV in the United States, it will be important for incarcerated persons to have access to HCV testing and treatment.

Screening for hepatitis C virus at the time of mammography using rapid diagnostic tests in women aged between 50 and 74 years (Mamm'OC NCT05067374).

Chronic hepatitis C Virus (HCV) infection presents a global health challenge, with significant morbidity and mortality worldwide. Despite remarkable progress in treatment options, achieving elimination targets by 2030, as set by the World Health Organization, remains elusive. Our study aimed to address this gap by integrating HCV screening into a national breast cancer screening program. Between March 2022 and March 2023, a prospective cross-sectional multicenter study was conducted in four radiology centers in Montpellier, France. We proposed HCV screening to consecutive women undergoing mammography, targeting 1,500 participants aged 50-74 years. A rapid diagnostic test (RDT) for HCV antibodies (HCV Ab) was performed on capillary whole blood, with positive cases undergoing serological and RNA confirmation. Participants also completed a questionnaire on demographic data and risk factors. Acceptance rates, HCV prevalence, and linkage to care were assessed. The acceptance rate for this integrated screening approach was 82.4%. Notably, the seroprevalence of HCV was found to be 0.65%. Linkage to care was prompt, and the cascade of care demonstrated successful treatment outcomes. Importantly, the majority of detected infections were successfully resolved. These findings underscore the feasibility and acceptability of integrating HCV screening with breast cancer screening programs providing updated prevalence data and valuable insights for refining future screening strategies.

Characterization of antibody-dependent cellular phagocytosis in patients infected with hepatitis C virus with different clinical outcomes.

Early neutralizing antibodies against hepatitis C virus (HCV) and CD8 + T cell effector responses can lead to viral clearance. However, these functions alone are not sufficient to protect patients against HCV infection, thus undefined additional antiviral immune mechanisms are required. In recent years, Fc-receptor-dependent antibody effector functions, particularly, antibody-dependent cellular phagocytosis (ADCP) were shown to offer immune protection against several RNA viruses. However, its development and clinical role in patients with HCV infection remain unknown. In this study, we found that patients with chronic GT1a or GT3a HCV infection had significantly higher concentrations of anti-envelope 2 (E2) antibodies, predominantly IgG1 subclass, than patients that cleared the viruses while the latter had antibodies with higher affinities. 97% of the patients with HCV had measurable ADCP of whom patients with chronic disease showed significantly higher ADCP than those who naturally cleared the virus. Epitope mapping studies showed that patients with antibodies that target antigenic domains on the HCV E2 protein that are known to associate with neutralization function are also strongly associated with ADCP, suggesting antibodies with overlapping/dual functions. Correlation studies showed that ADCP significantly correlated with plasma anti-E2 antibody levels and neutralization function regardless of clinical outcome and genotype of infecting virus, while a significant correlation between ADCP and affinity was only evident in patients that cleared the virus. These results suggest ADCP was mostly driven by antibody titer in patients with chronic disease while maintained in clearers due to the quality (affinity) of their anti-E2 antibodies despite having lower antibody titers.

Identification of novel neutralizing determinants for protection against HCV.

BACKGROUND AND AIMS: HCV evasion of neutralizing antibodies (nAb) results in viral persistence and poses challenges to the development of an urgently needed vaccine. N-linked glycosylation of viral envelope proteins is a key mechanism for such evasion. To facilitate rational vaccine design, we aimed to identify determinants of protection of conserved neutralizing epitopes. APPROACH AND RESULTS: Using a reverse evolutionary approach, we passaged genotype 1a, 1b, 2a, 3a, and 4a HCV with envelope proteins (E1 and E2) derived from chronically infected patients without selective pressure by nAb in cell culture. Compared with the original viruses, HCV recombinants, engineered to harbor substitutions identified in polyclonal cell culture-passaged viruses, showed highly increased fitness and exposure of conserved neutralizing epitopes in antigenic regions 3 and 4, associated with protection from chronic infection. Further reverse genetic studies of acquired E1/E2 substitutions identified positions 418 and 532 in the N1 and N6 glycosylation motifs, localizing to adjacent E2 areas, as key regulators of changes of the E1/E2 conformational state, which governed viral sensitivity to nAb. These effects were independent of predicted glycan occupancy. CONCLUSIONS: We show how N-linked glycosylation motifs can trigger dramatic changes in HCV sensitivity to nAb, independent of glycan occupancy. These findings aid in the understanding of HCV nAb evasion and rational vaccine design, as they can be exploited to stabilize the structurally flexible envelope proteins in an open conformation, exposing important neutralizing epitopes. Finally, this work resulted in a panel of highly fit cell culture infectious HCV recombinants.

Evidence for the elimination of viral hepatitis B and C in Egypt: Results of a nationwide survey in 2022.

INTRODUCTION: Viral hepatitis C (HCV) and B (HBV) were at the top of Egypt's most significant public health challenges, with an estimated 14.7% of its population having antibodies to HCV in 2008. Egypt issued an ambitious action plan in 2014 to eliminate viral hepatitis through strengthening infection control and improving patient care. In 2018, an extensive HCV mass screening campaign was conducted for the entire country's population with treating more than 4 million patients with antivirals. This study aimed to evaluate the current prevalence of viral hepatitis in Egypt after all these efforts. METHODS: A cross-sectional household cluster survey was conducted in all 27 Egyptian governorates to obtain a representative sample of Egypt's population. Subjects aged 1-70 years were interviewed using a standardised questionnaire that included demographics, viral hepatitis knowledge, previous infection and risk factors data. Laboratory testing was performed for all subjects for anti-HCV and HBsAg using chemiluminescence. Subjects positive for anti-HCV were further tested for HCV-RNA by RT-PCR. Prevalence rates were calculated by demographic groups and compared to the demographic health survey 2015 results. RESULTS: Of 20 881 subjects interviewed, 48.8% were males, 20.2% were children <15 years of age, and 53.7% were residents of rural areas. Of all subjects, 92 (0.4%) were HCV-infected, 1577 (7.6%) were anti-HCV positive and 177 (0.8%) were HBV-chronically infected, including one patient who had mixed HBV and HCV current infection. The prevalence of HCV-current and HBV chronic infections decreased by 93% and 20%, respectively, compared to 2015. CONCLUSIONS: Egypt achieved the elimination of the viral hepatitis goal. To maintain low rates of viral hepatitis, community health education, in addition to maintaining infection control and blood safety programs, is essential.

Implementation of Universal Hepatitis C Virus Screening in a Tertiary Cancer Center.

BACKGROUND: The prevalence of chronic hepatitis C virus (HCV) infection in the United States is ≤1%. Universal HCV screening is recommended nationwide. Here we describe our experience implementing universal HCV screening at a cancer center. METHODS: In October 2016, universal HCV screening with HCV antibody (anti-HCV) was initiated for all new outpatients. Universal screening was promoted through widespread provider education, orders in the Epic electronic health records (EHRs), SmartSets, and automated EHR reminders. The effort focused on patients with solid tumors, because universal screening in patients with hematologic malignancies was already standard practice. Primary outcomes were the proportion of patients screened and the proportion of patients with reactive anti-HCV test results linked to HCV care. The secondary outcome was the incidence of HCV-associated hepatocellular carcinoma as a second primary malignancy (HCC-SPM) in patients with a history of other cancers before HCC diagnosis. Epic's Reporting Workbench Business Intelligence tools were used. Statistical significance was defined as P<.05 on chi-square analysis. RESULTS: From April 2016 through April 2023, 56,075 patients with solid tumors were screened for HCV, of whom 1,300 (2.3%) had reactive anti-HCV test results. The proportion of patients screened was 10.1% in the 6 months before study implementation and 34.4% in the last 6 months of the study (P<.001). HCV screening was ordered using SmartSets in 39,332 (45.8%) patients and in response to automated EHR reminders in 10,972 (12.8%) patients. Most patients with reactive anti-HCV test results were linked to care (765/1,300; 59%), most with proven HCV infection were treated (425/562; 76%), and most treated patients achieved sustained virologic response (414/425; 97%). The incidence of HCC-SPMs was 15% in historical controls treated from 2011 to 2017 and 5.7% following implementation of universal screening (P=.0002). CONCLUSIONS: Universal HCV screening can be successfully implemented in cancer hospitals using an EHR-based multipronged approach to eliminate HCV and prevent HCV-associated HCC-SPMs.

Glycylglycine promotes the solubility and antigenic utility of recombinant HCV structural proteins in a point-of-care immunoassay for detection of active viremia.

BACKGROUND: Although E. coli is generally a well-opted platform for the overproduction of recombinant antigens as heterologous proteins, the optimization of expression conditions to maximize the yield of functional proteins remains empirical. Herein, we developed an optimized E. coli (BL21)-based system for the overproduction of soluble immunoreactive HCV core/envelope proteins that were utilized to establish a novel immunoassay for discrimination of active HCV infection. METHODS: The core/E1-E2 genes were amplified and expressed in E. coli BL21 (DE3) in the absence/presence of glycylglycine. The antigenic performance of soluble proteins was assessed against 63 HCV-seronegative (Ab-) sera that included normal and interferent sera (HBV and/or chronic renal failure), and 383 HCV-seropositive (Ab+) samples that included viremic (chronic/relapsers) and recovered patients' sera. The color intensity (OD450) and S/Co values were estimated. RESULTS: The integration of 0.1-0.4M glycylglycine in the growth media significantly enhanced the solubility/yield of recombinant core and envelope proteins by ~ 225 and 242 fold, respectively. This was reflected in their immunoreactivity and antigenic performance in the developed immunoassay, where the soluble core/E1/E2 antigen mixture showed 100% accuracy in identifying HCV viremic sera with a viral RNA load as low as 3800 IU/mL, without cross-reactivity against normal/interferent HCV-Ab-sera. The ideal S/Co threshold predicting active viremia (> 2.75) showed an AUC value of 0.9362 (95% CI: 0.9132 to 0.9593), with 87.64, 91.23% sensitivity and specificity, and 94.14, 82.11% positive and negative predictive values, respectively. The different panels of samples assayed with our EIA showed a good concordance with the viral loads and also significant correlations with the golden standards of HCV diagnosis in viremic patients. The performance of the EIA was not affected by the immunocompromised conditions or HBV co-infection. CONCLUSION: The applicability of the proposed platform would extend beyond the reported approach, where glycylglycine, low inducer concentration and post-induction temperature, combined with the moderately-strong constitutive promoter enables the stable production of soluble/active proteins, even those with reported toxicity. Also, the newly developed immunoassay provides a cost-effective point-of-care diagnostic tool for active HCV viremia that could be useful in resource-limited settings.

Seroprevalence of hepatitis B, C, and D and associated factors in the semi-isolated Yanomami Amazonian indigenous community.

BACKGROUND: Viral hepatitis is a significant health concern among indigenous population in the Americas. In Brazil, reports find high endemicity of HBV and HDV infections has been reported in several indigenous groups. However, few studies have documented the prevalence of HBV, HCV and HDV in the Yanomami. In this study, the prevalence of hepatitis B, C, and D serological markers and potential risk factors were investigated to provide guidance for the development of strategies aimed at reducing viral transmission in the Yanomami indigenous villages. METHODS: This cross-sectional study was carried out in March 2015 and included 430 individuals from four Yanomami villages: Alapusi (n = 78), Castanha/Ahima (n = 126), Gasolina (n = 105), and Taibrapa (n = 121). A rapid test was used for detection of HBsAg and anti-HCV and chemiluminescent immunoassay for anti-HBs, anti-HBc, and anti-HDV antibodies. RESULTS: HBsAg, anti-HBc, and anti-HBs were detected in 8.8, 45.5, and 49.4% of the participants, respectively. The estimated HBV status: current infection 9.6% (38/395); resolved infection 43.3% (171/395); vaccine immunity 20.5% (81/395), and susceptible to HBV 26.6% (105/395). Gasolina presented the lowest prevalence of HBV infection (6.5%) and the highest prevalence of vaccine immunity (26.9%). Children < 15 years old were highly susceptible to infection, as 53.1% did not have antibodies to HBV, while more than 80% of individuals over 45 years of age had been exposed to HBV. The markers for HDV were founded among 12.5% (4/32) of the HBsAg carriers. Anti-HCV was identified in all villages, with the highest prevalence in Alapusi (5.1%). Possible risk factors such as the use of piercings, tattoos, and contact with prospectors showed no statistical difference between the groups. CONCLUSIONS: Viral hepatitis B and serological markers for HCV and HDV were found to be widely distributed among the Yanomami indigenous community, while the prevalence of vaccine immunity to HBV was low. This finding reinforces the importance of promoting systematized diagnostic and vaccination strategies in indigenous communities. Our data confirm that isolated and difficult-to-reach indigenous communities lack appropriate access to diagnosis, treatment, and vaccination.

Prevalence of hepatitis B and C infection and linkage to care among patients with Non-Communicable Diseases in three rural Rwandan districts: a retrospective cross-sectional study.

INTRODUCTION: Rwanda's Hepatitis C elimination campaign has relied on mass screening campaigns. An alternative "micro-elimination" strategy focused on specific populations, such as non-communicable disease (NCD) patients, could be a more efficient approach to identifying patients and linking them to care. METHODS: This retrospective cross-sectional study used routine data collected during a targeted screening campaign among NCD patients in Kirehe, Kayonza, and Burera districts of Rwanda and patients receiving oncology services from the Butaro District Hospital. The campaign used rapid diagnostic tests to screen for Hepatitis B surface antigen (HBsAg) and Hepatitis C antibody (anti-HCV). We reported prevalences and 95% confidence intervals for HBsAg and anti-HCV, assessed for associations between patients' clinical programs and hepatitis B and C, and reported cascade of care for the two diseases. RESULTS: Out of 7,603 NCD patients, 3398 (45.9%) self-reported a prior hepatitis screening. Prevalence of HBsAg was 2.0% (95% CI: 1.7%-2.3%) and anti-HCV was 6.7% (95% CI: 6.2%-7.3%). The prevalence of HBsAg was significantly higher among patients < 40 years (2.4%). Increased age was significantly associated with anti-HCV (12.0% among patients ≥ 70 years). Of the 148 individuals who screened positive for HbsAg, 123 had viral load results returned, 101 had detectable viral loads (median viral load: 451 UI/mL), and 12 were linked to care. Of the 507 individuals who screened positive for anti-HCV, 468 had their viral load results returned (median viral load: 1,130,000 UI/mL), 304 had detectable viral loads, and 230 were linked to care. CONCLUSION: Anti-HCV prevalence among Rwandan patients with NCD was high, likely due to their older age. NCD-HCV co-infected patients had high HCV viral loads and may be at risk of poor outcomes from hepatitis C. Hepatitis C micro-elimination campaigns among NCD patients are a feasible and acceptable strategy to enhance case detection in this high-prevalence population with elevated viral loads and may support linkage to care for hepatitis C among elderly populations.