Incidences of new hepatitis B infection and anti-hepatitis B core-negative occult hepatitis B infection among Japanese blood donors in relation to anti-hepatitis B surface antigen levels.

A transfusion-transmitted hepatitis B virus (HBV) infection caused by blood only positive for anti-hepatitis B surface antigen (anti-HBs) was reported. Occult HBV infection (OBI) with sole anti-HBs among blood donors is an issue. The incidence of HBV infection among repeat blood donors was investigated with a detailed HBV infection phase, focusing on the influence of anti-HBs level. This study followed 3 435 653 donors for HBV DNA conversion over 4 years and 9 months. Infection phase was determined based on marker changes over DNA conversion. This study identified 115 hepatitis B surface antigen (HBsAg) conversions, 72 DNA-only conversions, and 15 DNA plus anti-hepatitis B core (anti-HBc) conversions among donors all negative for HBV DNA, HBsAg, and anti-HBc. Total incidence was 2.38/100 000 person-years (PY). None of these 202 new HBV infections arose in the group with anti-HBs titer ≥ 10 mIU/mL. In total, 30 anti-HBc-negative OBIs were identified (incidence; 0.35/100 000 PY); 7 showed typical secondary anti-HBs response, and 23 showed stable anti-HBc and anti-HBs levels at DNA conversion. The HBV infection-protective ability of anti-HBs ≥ 10 mIU/mL was reinforced. In addition to new infections, the blood donor population includes anti-HBc-positive- and negative OBI with immune reactions or abortive HBV infection.

Hepatitis C Virus as a Possible Helper Virus in Human Hepatitis Delta Virus Infection.

Previous studies reported that the hepatitis C virus (HCV) could help disseminate the hepatitis D virus (HDV) in vivo through the unrelated hepatitis B virus (HBV), but with essentially inconclusive results. To try to shed light on this still-debated topic, 146 anti-HCV-positive subjects (of whom 91 HCV/HIV co-infected, and 43 with prior HCV eradication) were screened for anti-HDV antibodies (anti-HD), after careful selection for negativity to any serologic or virologic marker of current or past HBV infection. One single HCV/HIV co-infected patient (0.7%) tested highly positive for anti-HD, but with no positive HDV-RNA. Her husband, in turn, was a HCV/HIV co-infected subject with a previous contact with HBV. While conducting a thorough review of the relevant literature, the authors attempted to exhaustively describe the medical history of both the anti-HD-positive patient and her partner, believing it to be the key to dissecting the possible complex mechanisms of HDV transmission from one subject to another, and speculating that in the present case, it may have been HCV itself that behaved as an HDV helper virus. In conclusion, this preliminary research, while needing further validation in large prospective studies, provided some further evidence of a role of HCV in HDV dissemination in humans.

Performance evaluation of the Access anti-HBc Total assay on the DxI 9000 Access Immunoassay Analyzer.

This study evaluated the diagnostic and analytical performances of the Access anti-HBc Total assay on the DxI 9000 Access Immunoassay System (Beckman Coulter Inc.). The multicenter study involved both prospective and retrospective sample collection from non-selected blood donors, hospitalized patients, or presumed anti-HBc Total positive individuals. Fresh/previously-frozen samples were tested with the Access and comparator assays to determine concordance; discrepant samples were tested with a second CE-marked assay. Among the 5983 non-selected fresh blood donor samples deemed anti-HBc Total negative, clinical specificity of the Access assay was 99.58% (95%CI: 99.38-99.72%). Clinical specificity was 99.27% (97.37-99.80%) among 273 anti-HBc Total negative hospitalized patient samples. Clinical sensitivity on 450 anti-HBc Total positive samples was 99.78% (98.75-99.96%). Evaluation in seroconversion panels revealed an average 1.4-day earlier detection versus a comparator assay. The Access assay demonstrated excellent clinical and analytical performances comparable to existing CE-marked anti-HBc Total assays. NCT04904835.

Seeing haemoglobin SC: Challenging the misperceptions.

Historically understudied and regarded as a mild type of sickle cell disease, HbSC can be associated with significant, progressive complications. Prospective studies are urgently needed to address treatment gaps for HbSC disease. Commentary on: Nelson et al. The clinical spectrum of HbSC sickle cell disease-not a benign condition. Br J Haematol 2024 (Online ahead of print). doi: 10.1111/bjh.19523.

Exploring the contrasts: in-depth analysis of human and canine mammary tumors - discoveries at the frontier.

We have examined genomic and transcriptomic abnormalities in human and canine samples to evaluate the canine model's validity for breast cancer research, emphasizing similarities and differences. Both species commonly utilize serum tumor markers and noncoding microRNAs. Immunohistochemistry and immunocytochemistry were employed to illustrate and compare results based on histological diagnoses. In addition to these factors, similarities exist in spontaneous tumor occurrence, age of onset, hormonal influences, and disease progression, including tumor size, clinical stage, and lymph node involvement. Molecular traits such as hormone receptor status, Epidermal Growth Factor Receptor (EGFR), and proliferation markers (Ki67) further endorse the canine model's utility in breast cancer studies. The advancement of technologies facilitates the identification of new cancer-associated molecules, both coding and non-coding genes, underscoring their potential as prognostic/diagnostic biomarkers and therapeutic targets.

Can the HB-EGF/EGFR pathway restore injured neurons?

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a transmembrane protein that, when cleaved by metalloproteases through a process called ectodomain shedding, binds to the EGF receptor (EGFR), activating downstream signaling. The HB-EGF/EGFR pathway is crucial in development and is involved in numerous pathophysiological processes. In this issue of The FEBS Journal, Sireci et al. reveal a previously unexplored function of the HB-EGF/EGFR pathway in promoting neuronal progenitor proliferation and sensory neuron regeneration in the zebrafish olfactory epithelium in response to injury.

Significance of hepatitis B virus capsid dephosphorylation via polymerase.

BACKGROUND: It is generally believed that hepatitis B virus (HBV) core protein (HBc) dephosphorylation (de-P) is important for viral DNA synthesis and virion secretion. HBV polymerase contains four domains for terminal protein, spacer, reverse transcriptase, and RNase H activities. METHODS: HBV Polymerase mutants were transfected into HuH-7 cells and assayed for replication and HBc de-P by the Phos-tag gel analysis. Infection assay was performed by using a HepG2-NTCP-AS2 cell line. RESULTS: Here, we show that a novel phosphatase activity responsible for HBc de-P can be mapped to the C-terminal domain of the polymerase overlapping with the RNase H domain. Surprisingly, while HBc de-P is crucial for viral infectivity, it is essential for neither viral DNA synthesis nor virion secretion. The potential origin, significance, and mechanism of this polymerase-associated phosphatase activity are discussed in the context of an electrostatic homeostasis model. The Phos-tag gel analysis revealed an intriguing pattern of "bipolar distribution" of phosphorylated HBc and a de-P HBc doublet. CONCLUSIONS: It remains unknown if such a polymerase-associated phosphatase activity can be found in other related biosystems. This polymerase-associated phosphatase activity could be a druggable target in clinical therapy for hepatitis B.

Assessment of biometeorological conditions in Eastern Mediterranean City Adana, Turkey from past to the future.

Human bioclimatic comfort (HBC) is an important subject of climatology in the field of physical geography. Human bioclimatic comfort (HBC) is the feeling of satisfied and comfortable within the ambient atmospheric thermal environment. Earth climate system has been exposed to changes from the beginning, but since 19th century human - induced factors have contributed to these changes. HBC is the combined effect of atmospheric conditions and affected by all the changes in them. Turkey is among the countries in Mediterranean region, expected to develop higher vulnerabilities to the (bio) climate hazards. Therefore, a Mediterranean city in the south of the country, Adana, was chosen as the study area. HBC assessment was made for the past (1961 - 1990), present (1991 - 2022), near (2030 - 2060) and distant future (2070 - 2100) using hourly - data from the official meteorology station between 1961 and 2022, daily data of the climate model scenarios (Representative Concentration Pathway - RCP4.5 and RCP8.5) and Physiological Equivalent Temperature (PET) index, the Rayman model and Geographic Information Systems in the spatial distribution of HBC conditions. The analysis showed that the prevalence of "cold" and "cool" stresses has decreased while that of "hot" and "very hot" stresses has increased from the past to the present in Adana. It is predicted that present conditions will continue in the near and distant future, all comfort ranges will increase to the following warm range and the ideal period for HBC conditions will be the winter season. In order to reduce the adverse HBC conditions in cities due to climate change by creating climate resilient, sustainable and healthy cities, urban design and planning principles should be followed from a geographical point of view.

Clinical Significance and Remaining Issues of Anti-HBc Antibody and HBV Core-Related Antigen.

Currently, hepatitis B virus (HBV) core antibody (anti-HBc antibody) and HBV core-related antigen (HBcrAg) are widely used as serum markers for diagnosis based on the HBV core region. This review focused on anti-HBc antibodies and HBcrAg and aimed to summarize the clinical significance of currently used assay systems and the issues involved. While anti-HBc is very significant for clinical diagnosis, the clinical significance of quantitative assay of anti-HBc antibody has been reevaluated with improvements in diagnostic performance, including its association with clinical stage and prediction of carcinogenesis and reactivation. In addition, concerning the new HBcrAg, a high-sensitivity assay method has recently been established, and its diagnostic significance, including the prediction of reactivation, is being reevaluated. On the other hand, the quantitative level of anti-HBc antibody expressed in different units among assay systems complicates the interpretation of the results. However, it is difficult to standardize assay systems as they vary in advantages, and caution is needed in interpreting the assay results. In conclusion, with the development of highly sensitive HBcrAg and anti-HBc antibody, a rapid and sensitive detection assay system has been developed and used in clinical practice. In the future, it is hoped that a global standard will be created based on the many clinical findings.

Toward a SARS-CoV-2 VLP Vaccine: HBc/G as a Carrier for SARS-CoV-2 Spike RBM and Nucleocapsid Protein-Derived Peptides.

Virus-like particles (VLPs) offer an attractive possibility for the development of vaccines. Recombinant core antigen (HBc) of Hepatitis B virus (HBV) was expressed in different systems, and the E. coli expression system was shown to be effective for the production of HBc VLPs. Here, we used HBc of the HBV genotype G (HBc/G) as a technologically promising VLP carrier for the presentation of spike RBM and nucleocapsid protein-derived peptides of the SARS-CoV-2 Delta variant for subsequent immunological evaluations of obtained fusion proteins. The major immunodominant region (MIR) of the HBc/G protein was modified through the insertion of a receptor binding motif (RBM) from the S protein or B-cell epitope-containing peptide from the N protein. The C-terminus of the two truncated HBc/G proteins was used for the insertion of a group of five cytotoxic T lymphocyte (CTL) epitopes from the N protein. After expression in E. coli, the MIR-derived proteins were found to be insoluble and were recovered through step-wise solubilization with urea, followed by refolding. Despite the lack of correct VLPs, the chimeric proteins induced high levels of antibodies in BALB/c mice. These antibodies specifically recognized either eukaryotically expressed hRBD or bacterially expressed N protein (2-220) of SARS-CoV-2. CTL-epitope-containing proteins were purified as VLPs. The production of cytokines was analyzed through flow cytometry after stimulation of T-cells with target CTL peptides. Only a protein with a deleted polyarginine (PA) domain was able to induce the specific activation of T-cells. At the same time, the T-cell response against the carrier HBc/G protein was detected for both proteins. The neutralization of SARS-CoV-2 pseudotyped murine retrovirus with anti-HBc/G-RBM sera was found to be low.

Seroprevalence Study of Anti-HBs Antibodies in the General Population of Vojvodina, Serbia.

Background and Objectives: Hepatitis B (HB) is a major global health problem and a potentially life-threatening disease caused by the hepatitis B virus (HBV). Also, it is an important cause of morbidity and mortality worldwide. Thanks to serological surveys, testing hepatitis B surface antibodies (anti-HBs) allows for serological assessments of their prevalence. The presence of anti-HBs, which protects against HBV infection, can be attributed to HB vaccination or natural HBV infection. The aim of our study was to evaluate the prevalence of HB surface antibodies (anti-HBs) as an indicator of collective immunity against HBV in the general population of the Autonomous Province of Vojvodina, Serbia. In addition, to distinguish whether anti-HBs were induced by the vaccine or by infection, the presence of antibodies against the hepatitis B core antigen (anti-HBc) was tested among those who were anti-HBs-positive. Materials and Methods: A total of 3467 residual sera samples, collected according to the specifications of the European Sero-Epidemiology Network 2 (ESEN2) study, from April 2015 to March 2016, were screened for the presence of anti-HBs using a chemiluminescence immunoassay. The difference between categorical variables was tested using the chi-square test. Results: Overall, 1870 (53.9%, 95% CI: 52.3-55.6) participants tested positive for anti-HBs. The median age of the study participants was 17 years (IQR 9-35). The anti-HB seroprevalence decreased with age, ranging from 80.7% (95% CI: 78.9-82.4) in the 1-19-year-old group to 16.4% (95% CI: 12.0-20.9) in the ≥60 years' age group. A total of 71 (3.8%, 95% CI: 2.9-4.7) serum samples were also anti-HBc-positive. Higher prevalence, but not statistically significant, was noticed in women (4.1%, 95% CI: 2.8-5.4) compared with men (3.5, 95% CI: 2.4-4.8) (p = 0.542). Also, there was a significant difference across the age groups, where those ≥60 years old had a prevalence of 65.9% (95% CI: 51.9-79.9) and the age category of 1-19-year-olds had just 0.2% (95% CI: 0.0-0.4) (p < 0.001). Conclusions: This study provides a comprehensive assessment of the anti-HBs seroprevalence of the general population in Vojvodina and provides an opportunity to better shape the national preventive strategy related to HBV.

Occult HBV Infection in Patients Infected by HIV or HCV: Comparison between HBV-DNA and Two Assays for HBsAg.

We investigated the frequency and serological correlates of occult hepatitis B virus infection (OBI) and the potential impact of a highly sensitive assay for HBsAg in subjects infected by human immunodeficiency virus (HIV) or hepatitis C virus (HCV), who are also at risk for hepatitis B virus (HBV) infection, often in an occult form. Samples from 499 patients with HIV, all HBsAg negative and anti-HBc positive, and 137 patients with HCV were tested for HBV-DNA, anti-HBc, anti-HBs, and HBsAg by a conventional and highly sensitive assay. HBV biomarkers were detected in 71.5% of HCV-RNA-positive, with a higher prevalence of cases positive only for anti-HBc in patients with HCV than in those with HIV. HBV-DNA was detectable in 0.6% of HIV-positive and 7.3% of HCV-RNA-positive patients. Among patients with HCV, four were positive for HBsAg and negative for HBV-DNA, bringing the rate of HBV-active infection in this group to 10.2%. Active HBV infection was not related to gender or specific patterns of HBV biomarkers but was higher in HCV patients coinfected by HIV compared to those infected only by HCV. Monitoring patients at high risk for HBV infection and reactivation may require testing for both HBV-DNA and HBsAg.

Blood donation screening for hepatitis B virus core antibodies: The importance of confirmatory testing and initial implication for rare blood donor groups.

BACKGROUND AND OBJECTIVES: Exclusion of blood donors with hepatitis B virus (HBV) core antibodies (anti-HBc) prevents transfusion-transmitted HBV infection but can lead to significant donor loss. As isolated anti-HBc positivity does not always indicate true past HBV infection, we have investigated the effectiveness of confirmatory anti-HBc testing and the representation of rare blood groups in anti-HBc-positive donors. MATERIALS AND METHODS: Three hundred ninety-seven HBV surface antigen-negative and anti-HBc initially reactive blood donor samples were tested by five different anti-HBc assays. RESULTS: Eighty percentage of samples reactive in Architect anti-HBc assay were positive by the Murex assay and anti-HBc neutralization. Eleven out of 397 samples showed discordant results in supplementary testing from the Murex confirmatory test result, and five remained undetermined following extensive serological testing. Thirty-eight percentage of anti-HBc-positive donors identified as minority ethnic groups compared with 11% representation in anti-HBc-negative donors (p < 0.0001); the frequency of the Ro blood group in anti-HBc-positive donors was 18 times higher in non-white ethnic groups. CONCLUSION: Using two anti-HBc assays effectively enabled the identification of HBV-exposed and potentially infectious donors, their deferral and potential clinical follow-up. However, the exclusion of confirmed anti-HBc-positive donors will still impact the supply of rare blood such as Ro.

Efficacy of combined HBsAg, anti-HBc and anti-HBs screening in minimizing transfusion transmission risk of hepatitis B infection in low resource setting.

Background: Hepatitis B Virus (HBV), and occult Hepatitis B in particular, is a major concern in the transfusion scenario, especially in endemic countries. This study attempted to estimate the prevalence of occult Hepatitis B infection (OBI) among voluntary blood donors in Maharashtra and to evaluate the role of combined screening strategy with implications in minimizing the current transfusion risks of seropositive OBI. Methods: Donor samples were collected from 80 eligible blood banks from various districts of Maharashtra between 2014 and 2017. ELISA based screening of HBsAg, anti-HBc (total and IgM), anti-HBs titres. Real-time quantitative PCR for Hepatitis B Virus DNA (HBV DNA) were performed for all HBsAg and or anti-HBc positive samples. Results: Out of 2398 samples tested, 20 (0.83%) samples were positive for HBsAg, whereas 547 (22.81%) were positive for anti-HBc. Out of 547 samples, 16 (2.92%) were positive for HBV DNA with median level at 247.89 IU/mL (IQR: 126.05-666.67 IU/mL). Anti-HBs levels were positive in 35.83% of OBI cases. ROC curve analysis showed that combined HBsAg, anti-HBc and anti-HBs (>50 mIU/mL) screening can more efficiently detect HBV infection in blood donors than HBsAg alone. Conclusions: A combined HBsAg, anti-HBc and anti-HBs screening for donor samples could be an alternative achievable strategy to minimize the HBV transmission as well as financial burden. In resource limited setup, the proposed combined strategy could be helpful in minimizing the risk of OBI transmission.

Major HBV splice variant encoding a novel protein important for infection.

BACKGROUND & AIMS: HBV expresses more than 10 spliced RNAs from the viral pregenomic RNA, but their functions remain elusive and controversial. To address the function of HBV spliced RNAs, we generated splicing-deficient HBV mutants and conducted experiments to assess the impact of these mutants on HBV infection. METHODS: HepG2-NTCP cells, human hepatocyte chimeric FRG mice (hu-FRG mice), and serum from patients with chronic hepatitis B were used for experiments on HBV infection. Additionally, SHifter assays and cryo-electron microscopy were performed. RESULTS: We found the infectivity of splicing-deficient HBV was decreased 100-1,000-fold compared with that of wild-type HBV in hu-FRG mice. Another mutant, A487C, which loses the most abundant spliced RNA (SP1), also exhibits severely impaired infectivity. SP1 hypothetically encodes a novel protein HBcSP1 (HBc-Cys) that lacks the C-terminal cysteine from full-length HBc. In the SHifter assay, HBcSP1 was detected in wild-type viral particles at a ratio of about 20-100% vs. conventional HBc, as well as in the serum of patients with chronic hepatitis B, but not in A487C particles. When infection was conducted with a shorter incubation time of 4-8 h at lower PEG concentrations in HepG2-NTCP cells, the entry of the A487C mutant was significantly slower. SP1 cDNA complementation of the A487C mutant succeeded in rescuing its infectivity in hu-FRG mice and HepG2-NTCP cells. Moreover, cryo-electron microscopy revealed a disulfide bond between HBc cysteine 183 and 48 in the HBc intradimer of the A487C capsid, leading to a locked conformation that disfavored viral entry in contrast to the wild-type capsid. CONCLUSIONS: Prior studies unveiled the potential integration of the HBc-Cys protein into the HBV capsid. We confirmed the proposal and validated its identity and function during infection. IMPACT AND IMPLICATIONS: HBV SP1 RNA encodes a novel HBc protein (HBcSP1) that lacks the C-terminal cysteine from conventional HBc (HBc-Cys). HBcSP1 was detected in cell culture-derived HBV and confirmed in patients with chronic infection by both immunological and chemical modification assays at 10-50% of capsid. The splicing-deficient mutant HBV (A487C) impaired infectivity in human hepatocyte chimeric mice and viral entry in the HepG2-NTCP cell line. Furthermore, these deficiencies of the splicing-deficient mutant could be rescued by complementation with the SP1-encoded protein HBcSP1. We confirmed and validated the identity and function of HBcSP1 during infection, building on the current model of HBV particles.

Chronic disease prevalence in a population with structural hemoglobin disorders undergoing diabetes diagnosis: A bayesian approach.

Background: Structural disorders of hemoglobin are a group of rare and fatal genetic diseases that disrupt the transport and exchange of oxygen in the blood, causing tissue damage and ultimately leading to chronic conditions. The hemoglobin (Hb) S variant predominantly impacts individuals of Afro-descendant heritage. A significant concentration of the Afro-descendant population in Colombia, notably 12.5 %, is found in the city of Cali. Previous research has identified this city's structural hemoglobin disorders prevalence rate of 3.78 %. The aim of this study was to determine the prevalence of HbC, HbS, HbF, and HbA2 variants within a population who underwent HbA1c testing, as well as the prevalence of chronic diseases among patients with these hemoglobin alterations, at a high-complexity hospital in the city of Cali from 2015 to 2019. Methods: A descriptive observational study was conducted, involving a study population that comprised patients with both suspected and monitored diagnoses of diabetes. The cohort was selected from a high-complexity hospital in Cali. A total of 15,608 patients were included in the analysis, all of whom underwent HbA1C measurement through capillary electrophoresis, which also offers an indirect diagnosis of certain structural disorders of hemoglobin. Bayesian methods were employed for frequency analysis. Results: Among the 15,608 patients assessed, 63.6 % (n = 9920) were women. The overall prevalence of structural hemoglobin disorders was 1.98 % (n = 287, 95 % CI = 1.77 %-2.21 %). The co-occurrence of diabetes and kidney disease emerged as the most prevalent combination of pathologies observed in individuals with HbC, for both men and women across various age groups: 18-42 (58.3 % and 50.0 % respectively), 43-55 (50.0 % for both), 56-65 (50.0 % and 37.5 % respectively), and >65 years (66.7 % and 57.1 % respectively). Conclusions: The observed prevalence of the studied variants exceeded 1 %, a threshold underscored by the World Health Organization (WHO) as epidemiologically significant. Among HbC and HbS-positive patients, the elevated prevalence of diabetes and kidney disease is a guiding factor in developing proactive prevention strategies.

Variant of uncertain significance Arg866Cys enhances disorderedness of h-BRCA1 (759-1064) region.

High structural flexibility has been reported in the central region of BRCA1, which hinders the structural and functional evaluations of mutations identified in the domain. Additionally, the need to categorize variants of unknown significance (VUS) has increased due to the growth in the number of variants reported in clinical settings. Therefore, unraveling the disease-causing mechanism of VUS identified in different functional domains of BRCA1 is still challenging. The current study uses a multidisciplinary approach to assess the structural impact of BRCA1 Arg866Cys mutation discovered in the central domain of BRCA1. The structural alterations have been characterized using Circular-Dichroism spectroscopy, nano-DSF, and molecular-dynamics simulations. BRCA1 Arg866Cys mutant demonstrated more flexibility and lesser affinity to DNA than the wild-type protein. The BRCA1(759-1064) wild-type protein was shown to be a ßII-rich protein with an induced D-O transition in the presence of DNA and 2,2,2-Trifluoroethanol (TFE). The protein's alpha-helical composition did not significantly change in the presence of TFE, besides an increase in ß-turns and loops. Under Transmission Electron Microscopes (TEM), amyloid-like fibrils structure was detected for Arg866Cys mutant whereas the wild-type protein showed amorphous aggregates. An increased ThT fluorescence indicated ß-rich composition and aggregation-prone behaviour for BRCA1 wild-type protein, while the fluorescence intensity was significantly quenched in the Arg866Cys mutant. Furthermore, increased conformational flexibility in the Arg866Cys variant was observed by principal component analysis. This work aims to comprehend the inherently disordered region of BRCA1 as well as the impact of missense mutations on folding patterns and binding to DNA for functional aspects.

Prevalence of occult hepatitis B virus infection and characterisation of hepatitis B surface antigen mutants among adults in western Croatia.

INTRODUCTION AND OBJECTIVES: Occult hepatitis B virus (HBV) infection (OBI) is characterised by low levels of hepatitis B virus (HBV) DNA in the blood/liver of patients with negative hepatitis B surface antigen (HBsAg). This study aimed to determine the OBI prevalence and virological characteristics (viral genotypes and HBsAg mutants) in patients with an "anti-HBc only" serological profile. MATERIALS AND METHODS: A total of 24 900 serum samples were routinely screened for hepatitis B markers over a five-year period. All anti-HBc-positive/HBsAg-negative/anti-HBs-negative sera were selected and analysed for the presence of HBV DNA. Mutational analyses of the HBs gene and polymerase gene sequences were performed. RESULTS: 1749 (7.02%) sera were anti-HBc positive, and 113 (0.45%) sera had an "anti-HBc only" serological profile (HBsAg/anti-HBs negative). HBV DNA was detected in 12/113 (10.61%) "anti-HBc only" positive sera, representing 0.048% of all routinely tested samples. Due to extremely low viremia, HBV genome was successfully sequenced in only two sera where subgenotype D3 was confirmed. Mutational analyses of the S gene revealed multiple missense mutations. In addition to the M133I, Y134F, and G145R mutations, already associated with diagnostic escape, we also found nine novel OBI-related S-gene mutations - S136Y, F158L, K160N, E164G, S167L, A168V, L175S, S210I and F212C. CONCLUSIONS: We detected multiple known and novel S gene mutations in 2/12 (16.6%) OBI cases, nevertheless, further studies are required to determine their role in the pathogenesis of OBI. Understanding the frequencies of clinically relevant HBV mutations may contribute to improvement of diagnostic protocols.

Structural implications of amyloidogenic rare variants Ser282Leu and Gln356Arg identified in h-BRCA1.

Preliminary studies have shown BRCA1 (170-1600) residues to be intrinsically disordered with unknown structural details. However, thousands of clinically reported variants have been identified in this central region of BRCA1. Therefore, we aimed to characterize h-BRCA1(260-553) to assess the structural basis for pathogenicity of two rare missense variants Ser282Leu, Gln356Arg identified from the Indian and Russian populations respectively. Small-angle X-ray scattering analysis revealed WT scores Rg -32 Å, Dmax -93 Å, and Rflex-51% which are partially disordered, whereas Ser282Leu variant displayed a higher degree of disorderedness and Gln356Arg was observed to be aggregated. WT protein also possesses an inherent propensity to undergo a disorder-to-order transition in the presence of cruciform DNA and 2,2,2-Trifluoroethanol (TFE). An increased alpha-helical pattern was observed with increasing concentration of TFE for the Gln356Arg mutant whereas Ser282Leu mutant showed significant differences only at the highest TFE concentration. Furthermore, higher thermal shift was observed for WT-DNA complex compared to the Gln356Arg and Ser282Leu protein-DNA complex. Moreover, mature amyloid-like fibrils were observed with 30 µM thioflavin T (ThT) at 37°C for Ser282Leu and Gln356Arg proteins while the WT protein exists in a protofibril state as observed by TEM. Gln356Arg formed higher-order aggregates with amyloidogenesis over time as monitored by ThT fluorescence. In addition, computational analyses confirmed larger conformational fluctuations for Ser282Leu and Gln356Arg mutants than for the WT. The global structural alterations caused by these variants provide a mechanistic approach for further classification of the variants of uncertain clinical significance in BRCA1 into amyloidogenic variants which may have a significant role in disease pathogenesis.

Immunoinformatics and Evaluation of Peptide Vaccines Derived from Global Hepatitis B Viral HBx and HBc Proteins Critical for Covalently Closed Circular DNA Integrity.

The Hepatitis B virus (HBV) HBx and HBc proteins play a crucial role in associating with covalently closed circular DNA (cccDNA), the primary factor contributing to intrahepatic viral persistence and a major obstacle in achieving a cure for HBV. The cccDNA serves as a reservoir for viral persistence. Targeting the viral HBc and HBx proteins' interaction with cccDNA could potentially limit HBV replication. In this study, we present epitopes identified from global consensus sequences of HBx and HBc proteins that have the potential to serve as targets for the development of effective vaccine candidates. Furthermore, conserved residues identified through this analysis can be utilized in designing novel, site-specific anti-HBV agents capable of targeting all major genotypes of HBV. Our approach involved designing global consensus sequences for HBx and HBc proteins, enabling the analysis of variable regions and highly conserved motifs. These identified motifs and regions offer potent sites for the development of peptide vaccines, the design of site-specific RNA interference, and the creation of anti-HBV inhibitors. The epitopes derived from global consensus sequences of HBx and HBc proteins emerge as promising targets for the development of effective vaccine candidates. Additionally, the conserved residues identified provide valuable insights for the development of innovative, site-specific anti-HBV agents capable of targeting all major genotypes of HBV from A to J.