Hepatocyte Intrinsic Innate Antiviral Immunity against Hepatitis Delta Virus Infection: The Voices of Bona Fide Human Hepatocytes.

The pathogenesis of viral infection is attributed to two folds: intrinsic cell death pathway activation due to the viral cytopathic effect, and immune-mediated extrinsic cellular injuries. The immune system, encompassing both innate and adaptive immunity, therefore acts as a double-edged sword in viral infection. Insufficient potency permits pathogens to establish lifelong persistent infection and its consequences, while excessive activation leads to organ damage beyond its mission to control viral pathogens. The innate immune response serves as the front line of defense against viral infection, which is triggered through the recognition of viral products, referred to as pathogen-associated molecular patterns (PAMPs), by host cell pattern recognition receptors (PRRs). The PRRs-PAMPs interaction results in the induction of interferon-stimulated genes (ISGs) in infected cells, as well as the secretion of interferons (IFNs), to establish a tissue-wide antiviral state in an autocrine and paracrine manner. Cumulative evidence suggests significant variability in the expression patterns of PRRs, the induction potency of ISGs and IFNs, and the IFN response across different cell types and species. Hence, in our understanding of viral hepatitis pathogenesis, insights gained through hepatoma cell lines or murine-based experimental systems are uncertain in precisely recapitulating the innate antiviral response of genuine human hepatocytes. Accordingly, this review article aims to extract and summarize evidence made possible with bona fide human hepatocytes-based study tools, along with their clinical relevance and implications, as well as to identify the remaining gaps in knowledge for future investigations.

Dismantling Barriers to Hepatitis B and Delta Screening, Prevention, and Linkage to Care among the PWUD Community in Philadelphia.

The prevalence of hepatitis B and delta viruses (HBV/HDV) among people who use drugs (PWUD) remains largely unknown. In the context of one Philadelphia-based harm reduction organization (HRO), this study aimed to assess HBV/HDV prevalence and facilitate linkage to care. Participants completed a demographic HBV/HDV risk factor survey and were screened for HBV and reflexively for HDV if positive for HBV surface antigen or isolated core antibody. Fisher's exact tests and regression were used to understand relationships between risks and HBV blood markers. Of the 498 participants, 126 (25.3%) did not have hepatitis B immunity, 52.6% had been vaccinated against HBV, and 17.9% had recovered from a past infection. Eleven (2.2%) participants tested positive for isolated HBV core antibody, 10 (2.0%) for HBV surface antigen, and one (0.2%) for HDV antibody. History of incarceration was associated with current HBV infection, while transactional sex and experience of homelessness were predictive of previous exposure. This study found high rates of current and past HBV infection, and a 10% HBV/HDV co-infection rate. Despite availability of vaccine, one quarter of participants remained vulnerable to infection. Findings demonstrate the need to improve low-threshold HBV/HDV screening, vaccination, and linkage to care among PWUD. The study also identified gaps in the HBV/HDV care cascade, including lack of point-of-care diagnostics and lack of support for HROs to provide HBV services.

[Sero-epidemiological characteristics of the hepatitis D virus infection among hepatitis B virus infected-patients at a single center in Xinjiang region].

Objective: To investigate the sero-epidemiological characteristics of the hepatitis D virus (HDV) infection among hepatitis B virus (HBV)-infected patients in Xinjiang region. Methods: A single-center cross-sectional analysis method was used to select 264 cases of hepatitis B virus infection who were hospitalized in the Center for Infectious Diseases and Liver Diseases of the First Affiliated Hospital of Xinjiang Medical University from August 2021 to January 2022. All patients were tested for HDV Ag, HDV IgM, HDV IgG, and HDV RNA. The infection status of hepatitis D virus was analyzed by grouping according to their clinical type, HBV viral load, and HBsAg level. A paired t-test was used for data with measurement data conforming to normal distribution. A paired rank sum test was used for data that did not conform to normal distribution before and after treatment. Results: A total of 36 cases (13.64%) and 26 cases (9.85%) were positive for HDV serological markers and HDV RNA. According to clinical type grouping, the positive rates of HDV serum markers in patients with chronic hepatitis B, hepatitis B-related cirrhosis, liver cancer, and liver failure were 13.46%, 12.43%, and 20.83%, respectively, and there was no statistically significant difference among the three groups (χ2=0.86, P=0.649). The positive rates of HDV RNA were 11.54%, 8.11%, and 20.83%, respectively, and there was no statistically significant difference among the three groups (χ2=4.015, P=0.134). According to HBV viral load grouping, the positive rates of HDV serum markers among patients with viral loads <20, 20-2 000, and >2 000 IU/ml were 17.15%, 7.81%, and 6.67%, respectively, and the difference was not statistically significant among the three groups (χ2=4.846, P=0.089). The positive rates of HDV RNA were 9.47%, 10.94%, and 10%, respectively, and the difference was not statistically significant among the three groups (χ2=0.113, P=0.945). According to HBsAg level grouping, the positive rates of HDV serum markers in HBsAg<0.05, 0.05~250, and >250 IU/ml were 14.29%, 16.67%, and 10.85%, respectively, and there was no statistically significance between the three groups (χ2=1.745, P=0.418). The positive rates of HDV RNA were 4.76%, 8.77%, and 11.63%, respectively, and there was no statistically significant difference among the three groups (χ2=1.221, P=0.543). Clinical outcome, disease course, HBV DNA, serological markers of viral hepatitis, routine blood test, biochemical indicators, coagulation function, and other laboratory indicators were compared between HDV serum marker and/or nucleic acid positive and negative patients, and there was no statistically significant difference (P>0.05). Conclusion: The positive rate of HDV serological markers and HDV RNA is 13.64% and 9.85%, respectively, at a single center in the Xinjiang region, and there is still a high HDV infection rate among the HBV-infected patients with low levels of viral load and HBsAg.

Hepatitis-D Virus Infection Is Not Impaired by Innate Immunity but Increases Cytotoxic T-Cell Activity.

Approximately 70 million humans worldwide are affected by chronic hepatitis D, which rapidly leads to liver cirrhosis and hepatocellular carcinoma due to chronic inflammation. The triggers and consequences of this chronic inflammation, induced by co-infection with the hepatitis D virus (HDV) and the hepatitis B virus (HBV), are poorly understood. Using CRISPR technology, we characterized the recognition of HDV mono- and co-infection by intracellular innate immunity and determined its influence on the viral life cycle and effector T-cell responses using different HBV and HDV permissive hepatoma cell lines. We showed that HDV infection is detected by MDA5 and -after a lag phase -induces a profound type I interferon response in the infected cells. The type I interferon response, however, was not able to suppress HDV replication or spread, thus providing a persistent trigger. Using engineered T-cells directed against the envelope proteins commonly used by HBV and HDV, we found that HDV immune recognition enhanced T-cell cytotoxicity. Interestingly, the T-cell effector function was enhanced independently of antigen presentation. These findings help to explain immune mediated tissue damage in chronic hepatitis D patients and indicate that combining innate triggers with T-cell activating therapies might allow for a curative approach.

Hepatitis D virus in 2021: virology, immunology and new treatment approaches for a difficult-to-treat disease.

Approximately 5% of individuals infected with hepatitis B virus (HBV) are coinfected with hepatitis D virus (HDV). Chronic HBV/HDV coinfection is associated with an unfavourable outcome, with many patients developing liver cirrhosis, liver failure and eventually hepatocellular carcinoma within 5-10 years. The identification of the HBV/HDV receptor and the development of novel in vitro and animal infection models allowed a more detailed study of the HDV life cycle in recent years, facilitating the development of specific antiviral drugs. The characterisation of HDV-specific CD4+ and CD8+T cell epitopes in untreated and treated patients also permitted a more precise understanding of HDV immunobiology and possibly paves the way for immunotherapeutic strategies to support upcoming specific therapies targeting viral or host factors. Pegylated interferon-α has been used for treating HDV patients for the last 30 years with only limited sustained responses. Here we describe novel treatment options with regard to their mode of action and their clinical effectiveness. Of those, the entry-inhibitor bulevirtide (formerly known as myrcludex B) received conditional marketing authorisation in the European Union (EU) in 2020 (Hepcludex). One additional drug, the prenylation inhibitor lonafarnib, is currently under investigation in phase III clinical trials. Other treatment strategies aim at targeting hepatitis B surface antigen, including the nucleic acid polymer REP2139Ca. These recent advances in HDV virology, immunology and treatment are important steps to make HDV a less difficult-to-treat virus and will be discussed.

Hepatitis delta: In vitro evaluation of cytotoxicity and cytokines involved in PEG-IFN therapy.

The treatment for hepatitis Delta virus (HDV) still consists of Pegylated interferon (PEG-IFN) combined with inhibitors of Hepatitis B virus (HBV) replication. In some patients may be occur a virological response, which means a negative HDV RNA 6 months after stopping treatment. In this study it was conducted an in vitro approach with the aim to mimic possible immunological events that are observed in patients responding to PEG-IFN therapy. Jurkat cells (human T lymphocyte cell line) were employed alone or co-cultured with THP-1 (human monocytic cell line) and stimulated with controls and HBV Surface Antigen (HBsAg), Small-Delta Antigen (SHDAg), and HBsAg + SHDAg combined. Twenty-four hours stimulation with SHDAg and/or HBSAg led to a toxic profile in a co-culture condition and cell supernatants were collected for cytokines quantification. PEG-IFN was added and cells were incubated for additional 24 h. Co-cultured cells incubated with the association (SHDAg + PEG-IFN) significantly produced levels of IFN-γ, IL-2 and IL-12. On the other hand, the HBsAg alone was able to inhibit the production of IFN-γ, suggesting that this antigen may hinder the treatment exclusively with PEG-IFN.

Reducción en la infección por VHB y VHD en dos poblaciones indígenas de la Amazonia peruana después de la vacunación contra la hepatitis B / Reduction of HBV and HDV infection in two indigenous peoples of Peruvian Amazon after the vaccination against hepatitis B

Resumen: Objetivo: Conocer el resultado de la vacunación contra la hepatitis B en las comunidades hiperendémicas Kandozi y Chapra de la Amazonia Peruana a partir de la prevalencia de infecciones por los virus de la hepatitis B (VHB) y Delta (VHD), ocho años después de iniciada la vacunación. Material y métodos: Se realizó un estudio transversal en 2 944 pobladores de 67 comunidades indígenas Kandozi y Chapra en abril de 2010. El tamizaje serológico para el antígeno de superficie del VHB (HBsAg), anticuerpos anti-HBc IgM e IgG, anticuerpos anti-HBs y anti-VHD se determinaron mediante pruebas de ELISA. Resultados: Las tasas de prevalencia del HBsAg, anti-HBc IgG, anti-HBs ≥10 mlUI/ml y anti-VHD fueron 2.3, 39.13, 50.95 y 2.11%, respectivamente. La prevalencia del HBsAg en niños <11 años fue cero. Entre los portadores del HBsAg, las tasas de prevalencia de sobreinfeccion por el VHD e infección aguda por el VHB fueron 2.11% (todos fueron >14 años) y 11.94%, respectivamente. Conclusiones: Estos hallazgos muestran la eliminación de portadores de VHB en niños <11 años, ocho años después de iniciada la vacunación contra el VHB.

Abstract: Objective: To determine the outcome of the vaccination against hepatitis, we determined the prevalence of hepatitis B virus (HBV) and hepatitis D virus (HDV) infections, eight years after introduction of the vaccination. Materials and methods: A cross-sectional study was performed in 2 944 participants of 67 Kandozi and Chapra indigenous peoples in April 2010. Serological screening for hepatitis B surface antigen (HBsAg), antibody anti-HBc IgM and IgG, antibody anti-HBs and anti-HDV were determined by ELISA tests. Results: The prevalence rates of HBsAg, anti-HBc total, anti-HBs ≥10 mlUI/ml and anti-HDV were 2.3, 39.13, 50.95 and 2.11%, respectively. The prevalence rate of HBsAg in children <11 years was 0%. Among carriers of HBsAg, the prevalence rates of HDV and acute HBV infections were 2.11% (all were >14 years) and 11.94%, respectively. HBsAg and anti-HBc total were associated with individuals ≥10 years (p<0.001). Conclusions: These findings show the elimination of HBV carriers in children <11 years, eight years following introduction of the vaccination against HBV.

Epidemiology of blood-borne viral infections in Afghanistan.

Although a few studies have been done on transmissible blood-borne viral infections in high-risk groups, little attention has been given to assessing the infection status of the general population in Afghanistan. To investigate the epidemiological status in the general population, we tested the serological markers of hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis delta virus (HDV), human immunodeficiency virus 1 (HIV-1) and human T-cell leukemia virus (HTLV) infections. In total, 492 samples were selected randomly from Nangarhar, Herat, Mazar-e Sharif, Kandahar, and Kabul from subjects between 25 and 70 years old. The samples were tested for the presence of HBsAg, anti-HBs, anti-HBc, anti-HDV, anti-HCV, anti-HIV-1 and anti-HTLV I/II antibodies using chemiluminescent immunoassays on Abbott Architect automated platforms. In addition, 220 HBsAg-positive samples identified among 5897 samples from the general population of the same regions of Afghanistan were included in the study and tested for both HBsAg and anti-HDV to investigate HDV prevalence in the country. Viral loads of HBV, HCV and HDV were determined in all seropositive samples using Ampliprep/Cobas TaqMan HBV, HCV, Test Roche (CA, USA), and an in-house method, respectively. Out of 492 samples, 31 (6.3%), 136 (27.6%) and 149 (30.3%) were found to be positive for HBsAg, anti-HBs and anti-HBc, respectively. Anti-HDV positivity was detected in five (2.1%) out of 234 HBsAg-positive samples (including 14 of the randomly selected samples that were not among the 220 previously identified as HBsAg positive). Only eight out of 492 (1.6%) subjects were positive for anti-HCV antibodies. Seven out of 489 (1.4%) were positive for anti-HIV-1 antibodies, and three out of 466 cases (0.6%) were positive for anti-HTLV I/II antibodies. These results suggest that Afghanistan is an intermediate endemic region for HBV, HDV and HCV infection. The prevalence of HIV-1 seems to be significantly higher than the global prevalence and that of the eastern Mediterranean region. In addition, the HTLV I/II screening results suggest that these viruses should be monitored in Afghanistan to confirm the trend observed in the current study.

The balance of type 1 and type 2 immune responses in the contexts of hepatitis B infection and hepatitis D infection.

BACKGROUND AND AIM: Hepatitis delta virus (HDV) infection is the most rapidly progressive chronic viral hepatitis. Little is understood about the immune responses to HDV. This study aims to characterize the systemic immune environments of hepatitis B virus (HBV) and HDV patients at various disease stages. METHODS: A total of 129 subjects were evaluated: 53 HBV, 43 HDV, and 33 healthy controls. HBV and HDV subjects were categorized by aspartate aminotransferase to platelet ratio index (APRI) into mild (APRI < 0.5), moderate, and severe (APRI > 1.0). Serum cytokines and immune markers were assessed at a single treatment-naïve time-point. RESULTS: Type 1 cytokines are elevated in both HBV and HDV. Both groups show higher tumor necrosis factor-α (TNF-α), interleukin (IL)-12p40, and C-X-C motif chemokine ligand 9 when compared with controls (all P < 0.05). However, only HBV group displayed elevated γ-interferon compared with controls. Type 2 cytokines are elevated in HBV. HBV group shows higher IL-4, IL-13, and C-C motif chemokine ligand (CCL) 26 compared with healthy controls and HDV. Chemokines CCL2 and CCL13 are lower in HDV. When assessing ratios, HDV displays higher γ-interferon/IL-4, TNF-α/IL-4, and TNF-α/IL-13 ratios than HBV and controls. CONCLUSION: Hepatitis B virus and HDV subjects show similarly elevated type 1 cytokines. HDV subjects display relatively lower type 2 cytokines. These differences in the systemic immune environments, particularly the predominance of type 1 responses, may contribute to the comparatively rapid progression of HDV disease. Characterization of the imbalance in type 1 and type 2 immunity unique HDV has the potential to provide immunological insights for designing therapeutic targets in HDV-associated disease progression.

Modeling hepatitis virus infections and treatment strategies in humanized mice.

Hepatitis viruses cause chronic liver diseases such as fibrosis, cirrhosis and hepatocellular carcinomas that are difficult to treat and constitute a global health problem. Species-specific viral tropism has limited the usefulness of small animal models to study the impact of viral hepatitis. Immunodeficient mice grafted with human hepatocytes are susceptible to hepatitis viruses B, C, D and E (HBV, HCV, HDV and HEV), developing full viral life cycles, and delivering a means to investigate virus-host interactions and antiviral treatments. These chimeric humanized mouse models have been further grafted with humanized immune systems to decipher immune responses following hepatotropic viral infections, the ensuing pathophysiology, and to test novel therapeutic strategies.

A new HDV mouse model identifies mitochondrial antiviral signaling protein (MAVS) as a key player in IFN-ß induction.

BACKGROUND & AIMS: Studying hepatitis delta virus (HDV) and developing new treatments is hampered by the limited availability of small animal models. Herein, a description of a robust mouse model of HDV infection that mimics several important characteristics of the human disease is presented. METHODS: HDV and hepatitis B virus (HBV) replication competent genomes were delivered to the mouse liver using adeno-associated viruses (AAV; AAV-HDV and AAV-HBV). Viral load, antigen expression and genomes were quantified at different time points after AAV injection. Furthermore, liver pathology, genome editing, and the activation of the innate immune response were evaluated. RESULTS: AAV-HDV infection initiated HDV replication in mouse hepatocytes. Genome editing was confirmed by the presence of small and large HDV antigens and sequencing. Viral replication was detected for 45days, even after the AAV-HDV vector had almost disappeared. In the presence of HBV, HDV infectious particles were detected in serum. Furthermore, as observed in patients, co-infection was associated with the reduction of HBV antigen expression and the onset of liver damage that included the alteration of genes involved in the development of liver pathologies. HDV replication induced a sustained type I interferon response, which was significantly reduced in immunodeficient mice and almost absent in mitochondrial antiviral signaling protein (MAVS)-deficient mice. CONCLUSION: The animal model described here reproduces important characteristics of human HDV infection and provides a valuable tool for characterizing the viral infection and for developing new treatments. Furthermore, MAVS was identified as a main player in HDV detection and adaptive immunity was found to be involved in the amplification of the innate immune response. Lay summary: Co-infection with hepatitis B and D virus (HBV and HDV, respectively) often causes a more severe disease condition than HBV alone. Gaining more insight into HDV and developing new treatments is hampered by limited availability of adequate immune competent small animal models and new ones are needed. Here, a mouse model of HDV infection is described, which mimics several important characteristics of the human disease, such as the initiation and maintenance of replication in murine hepatocytes, genome editing and, in the presence of HBV, generation of infectious particles. Lastly, the involvement of an adaptive immunity and the intracellular signaling molecule MAVS in mounting a strong and lasting innate response was shown. Thus, our model serves as a useful tool for the investigation of HDV biology and new treatments.

Modification of the hepatitis B virus envelope protein glycosylation pattern interferes with secretion of viral particles, infectivity, and susceptibility to neutralizing antibodies.

UNLABELLED: The envelope proteins of hepatitis B virus (HBV) bear an N-linked glycosylation site at N146 within the immunodominant a-determinant in the antigenic loop (AGL) region. This glycosylation site is never fully functional, leading to a nearly 1/1 ratio of glycosylated/nonglycosylated isoforms in the viral envelope. Here we investigated the requirement for a precise positioning of N-linked glycan at amino acid 146 and the functions associated with the glycosylated and nonglycosylated isoforms. We observed that the removal of the N146 glycosylation site by mutagenesis was permissive to envelope protein synthesis and stability and to secretion of subviral particles (SVPs) and hepatitis delta virus (HDV) virions, but it was detrimental to HBV virion production. Several positions in the AGL could substitute for position 146 as the glycosylation acceptor site. At position 146, neither a glycan chain nor asparagine was absolutely required for infectivity, but there was a preference for a polar residue. Envelope proteins bearing 5 AGL glycosylation sites became hyperglycosylated, leading to an increased capacity for SVP secretion at the expense of HBV and HDV virion secretion. Infectivity-compatible N-glycosylation sites could be inserted at 3 positions (positions 115, 129, and 136), but when all three positions were glycosylated, the hyperglycosylated mutant was substantially attenuated at viral entry, while it acquired resistance to neutralizing antibodies. Taken together, these findings suggest that the nonglycosylated N146 is essential for infectivity, while the glycosylated form, in addition to its importance for HBV virion secretion, is instrumental in shielding the a-determinant from neutralizing antibodies. IMPORTANCE: At the surface of HBV particles, the immunodominant a-determinant is the main target of neutralizing antibodies and an essential determinant of infectivity. It contains an N-glycosylation site at position 146, which is functional on only half of the envelope proteins. Our data suggest that the coexistence of nonglycosylated and glycosylated N146 at the surface of HBV reflects the dual function of this determinant in infectivity and immune escape. Hence, a modification of the HBV glycosylation pattern affects not only virion assembly and infectivity but also immune escape.

Progression to cirrhosis, hepatocellular carcinoma and liver-related mortality in chronic hepatitis B patients in Italy.

BACKGROUND: The natural history of chronic hepatitis B is variable. We evaluated some of the risk factors for cirrhosis, hepatocellular carcinoma and liver-related mortality in Italian patients with chronic hepatitis B. METHODS: A cohort of 105 untreated patients with chronic hepatitis B without cirrhosis at diagnosis was followed prospectively for a mean period of 23 years. Clinical, histological and ultrasound examinations, biochemical and virological tests, and causes of death were analyzed. RESULTS: Forty-two (40%) patients became inactive carriers and 63 (60%) showed persistent alanine aminotransferase elevation: 13 (13%) associated with HBeAg persistence, 35 (33%) with detectable serum HBV-DNA but HBeAg-negative, 11 (10%) with concurrent virus infection and 4 (4%) with non-alcoholic fatty liver disease. Cirrhosis incidence was 1.56/100 person-years. Older age and sustained HBV replication predicted cirrhosis occurrence independently. Hepatocellular carcinoma incidence was 2.1/100 person-years in patients who developed cirrhosis and 0.06 in those who did not. Cirrhosis occurrence was associated with an increased risk of hepatocellular carcinoma (hazard ratio 20.4, 95% confidence interval 2.54-167.5) and liver-related death (16.5, 2.0-138.8). CONCLUSIONS: In Italian patients with chronic hepatitis B cirrhosis strongly predicts hepatocellular carcinoma occurrence and disease-related mortality, thus indicating that early antiviral treatment should be instituted before cirrhosis occurrence.

Comparison of the histological and serological parameters of patients with hepatitis delta virus in active and inactive hepatitis B virus carriers.

OBJECTIVE: To assess the histological and serological parameters of patients with hepatitis delta virus (HDV) in active HBV versus inactive HBV carriers. STUDY DESIGN: An observational study. PLACE AND DURATION OF STUDY: Medical Unit IV at Liaquat University Hospital, Jamshoro, Sindh, from June 2008 to September 2011. METHODOLOGY: This study included 49 consecutive inactive HBV carriers who were HBsAg-positive, HBV DNA-negative, anti-D antibody-positive, and HDV RNA-positive, as well as 277 patients with active HBV who were HBsAg-positive, anti- HDV antibody-positive, HDV RNA-positive, and demonstrated > 20,000 IU/mL HBV DNA and > 2 (ULN) serum glutamic pyruvic transaminase (SGPT). Informed consent was obtained from each patient. Liver biopsies were obtained and the staging of fibrosis was performed according to the METAVIR scoring system. Continuous variables such as age, SGPT, platelet count, and the HBV DNA level were computed as the mean ± standard deviation. Categorical variables such as gender and stage of fibrosis are expressed as percentages. All data were processed using SPSS version 16. RESULTS: This study included 49 patients in an inactive HBV group. Fibrosis stage 0 was observed in 37 (75.5%) patients and 12 (24.5%) were stage 1. Among the 277 patients with active disease, fibrosis stage 0 was present in 7 (2.5%) patients, stage 1 in 31 (11.2%) patients, stage 2 in 172 (62.1%) patients, stage 3 in 44 (15.9%) patients and stage 4 in 23 (8.3%) patients. CONCLUSION: HDV in active HBV carriers is severe on its initial presentation and requires prompt treatment whereas in inactive HBV carriers demonstrates an indolent course.

HBV life cycle is restricted in mouse hepatocytes expressing human NTCP.

Recent studies have revealed that human sodium taurocholate cotransporting polypeptide (SLC10A1 or NTCP) is a functional cellular receptor for hepatitis B virus (HBV). However, whether human NTCP can support HBV infection in mouse hepatocyte cell lines has not been clarified. Because an HBV-permissible mouse model would be helpful for the study of HBV pathogenesis, it is necessary to investigate whether human NTCP supports the susceptibility of mouse hepatocyte cell lines to HBV. The results show that exogenous human NTCP expression can render non-susceptible HepG2 (human), Huh7 (human), Hepa1-6 (mouse), AML-12 (mouse) cell lines and primary mouse hepatocyte (PMH) cells susceptible to hepatitis D virus (HDV) which employs HBV envelope proteins. However, human NTCP could only introduce HBV susceptibility in human-derived HepG2 and Huh7 cells, but not in mouse-derived Hepa1-6, AML-12 or PMH cells. These data suggest that although human NTCP is a functional receptor that mediates HBV infection in human cells, it cannot support HBV infection in mouse hepatocytes. Our study indicated that the restriction of HBV in mouse hepatocytes likely occurs after viral entry but prior to viral transcription. We have excluded the role of mouse hepatocyte nuclear factors in the restriction of the HBV life cycle and showed that knockdown or inhibition of Sting, TBK1, IRF3 or IRF7, the components of the anti-viral signaling pathways, had no effect on HBV infection in mouse hepatocytes. Therefore, murine restriction factors that limit HBV infection need to be identified before a HBV-permissible mouse line can be created.

Perspectives for a vaccine against hepatitis delta virus.

Hepatitis delta virus (HDV) causes severe hepatitis in carriers of hepatitis B virus (HBV). In ~90% of patients, HDV persists together with HBV and causes early development of cirrhosis and liver carcinoma. Worldwide ~15 million people are coinfected with HBV-HDV. Specific defects in the immune response causing persistence of the virus have not been identified. Several approaches to develop a vaccine to prevent superinfection in the preclinical model of the woodchuck have failed. Recent findings show that a DNA prime and viral vectors boost immunization regimen can induce a HDV specific CD8 T cell response and can prevent HDV infection in simultaneous infection of woodchuck hepatitis virus-HDV. The vaccine-induced specific CD8 T cell response is effective in preventing HDV replication and spread in the liver. However, the perspectives for a HDV vaccine against genotype-1 to prevent superinfection are much less promising. The T-cell response induced by the current DNA prime and viral vector boost immunization in the preclinical woodchuck model seems insufficient to prevent the spread of HDV in chronic HBV carriers. A more potent vaccine and repeated vaccinations are necessary to induce a HDV-specific T-cell response, which may prevent superinfection in HBsAg carriers.

ADARs: viruses and innate immunity.

Double-stranded RNA (dsRNA) functions both as a substrate of ADARs and also as a molecular trigger of innate immune responses. ADARs, adenosine deaminases that act on RNA, catalyze the deamination of adenosine (A) to produce inosine (I) in dsRNA. ADARs thereby can destablize RNA structures, because the generated I:U mismatch pairs are less stable than A:U base pairs. Additionally, I is read as G instead of A by ribosomes during translation and by viral RNA-dependent RNA polymerases during RNA replication. Members of several virus families have the capacity to produce dsRNA during viral genome transcription and replication. Sequence changes (A-G, and U-C) characteristic of A-I editing can occur during virus growth and persistence. Foreign viral dsRNA also mediates both the induction and the action of interferons. In this chapter our current understanding of the role and significance of ADARs in the context of innate immunity, and as determinants of the outcome of viral infection, will be considered.

Are patients with primary hepatocellular carcinoma infectious of hepatitis B, C and D viruses?

Primary HepatoCellular Carcinoma (PHCC) has been strongly associated with HBV and HCV infections among other aetiological factors. However; do the patients still spread the viruses? This study involved forty one Nigerian adult patients with PHCC and 45 controls who were tested for HBsAg, HBeAg, Anti-HBe, Anti-HBs, anti-HCV IgM and IgG, anti-HDV and HDV antigen using ELISA. Statistical analysis was carried out with the student - t - test and Mc Nemar test at p < 0.05. The subjects consisted of male:female ratio of 3:1 for both the PHCC patients and controls. Evidence of exposure to hepatitis B, C and D viruses was detected in 95.1%, 44% and 0% of the patients respectively while the respective values of 24%, 11.1% and 0% were obtained for the controls. Indication for high (HBeAg) and low (anti HBe) HBV viral replication, and acute HBV infection were detected in 12.5%, 92.7% and 2.2% respectively among the patients while only 35.6% of the controls had low HBV viral replication. Acute and chronic infections of HCV were also found in 26.8% and 24.4% of the patients respectively compared to the respective values of 2.2% and 11.1% of the controls. Occult HBV infection occurred in equal proportions (11%) of both the patients (31.7%) and controls (35.6%). In conclusion, infectious HBV and HCV particles are present among Nigerian patients with PHCC while HDV infection is uncommon. Hence, safe medical care should be practised for all patients with PHCC while relatives should be screened for these viruses.

[Viral markers of hepatitis B, C and D and HB vaccination status of a health care team in a rural district of Cameroon]. / Marqueurs d'infection par virus des hépatites B, C et D et vaccination contre l'hépatite B chez des personnels de santé d'un district rural du Cameroun.

UNLABELLED: Ninety-three health care workers (HCW) in the Tokombere sahelian district volunteered to participate in a trial to investigate viral markers of hepatitis B, C, and D and HB vaccination status. METHODS: . Sera were tested using the Vikia HBsAg kit followed by CMIA for detection of HBsAg, anti-HBs, anti-HBc, and anti-HCV. HBsAg-positive HCW were tested for HBV-DNA, anti-HDV, and, if positive for anti-HDV, HDV-RNA. RESULTS: Analysis of anti-HBc positivity indicated that 91% of HCW had been infected by HBV, regardless of vaccination history. Vikia HBsAg results were confirmed by chemiluminescent microparticle immunoassay (CMIA) in all HCW and were positive in 17 HCW with virus load >2000 IU/mL in 6 and HDV co-infection in 6. Anti-HCV was found in 6 HCW. Among the 55 HCW that had not been vaccinated, only 3 needed vaccination because of anti-HBc negativity. Among HCW considered for HBV treatment, one patient presenting HBV/HDV co-infection was excluded after diagnosis of hepatocarcinoma. CONCLUSION: Systematic HB vaccination of new HCW appears unnecessary in this rural region of Africa. Anti-HBc screening is cost-effective for identifying HCW requiring vaccination. Vikia HBsAg is effective for point-of-care screening. We underline the need for universal early (preferably neonatal) HB vaccination and for availability of anti-HBV drug in limited-resource countries.