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.

A combination of α-fetoprotein, midkine, thioredoxin and a metabolite for predicting hepatocellular carcinoma.

INTRODUCTION AND OBJECTIVES: The heterogenous nature of hepatocellular carcinoma (HCC) motivated this attempt at developing and validating a model based on combined biomarkers for improving early HCC detection. PATIENTS/MATERIALS AND METHODS: This study examined 196 patients for an estimation study (104 patients with HCC, 52 with liver cirrhosis and 40 with liver fibrosis) and 122 patients for the validation study (80 patients with HCC, 42 with liver cirrhosis). All patients were positive for hepatitis C virus. Four markers were measured: Midkine and thioredoxin using ELISA, 1-methyladenosine and 1-methylguanosine using a gas chromatography-mass spectrometry (GC-MS). The results were compared with alpha-fetoprotein (AFP). The performance of the model was estimated in BCLC, CLIP and Okuda staging systems of HCC. RESULTS: The model yielded high performance with an area under ROC (AUC) of 0.94 for predicting HCC in patients with liver cirrhosis, compared with AUC of 0.69 for AFP. This model had AUCs of 0.93, 0.94 and 0.94 in patients who had only one single nodule, absent macrovascular invasion and tumor size <2cm, respectively, compared with AUCs of 0.71, 0.6 and 0.59 for AFP. The model produced AUCs of 0.91 for BCLC (0-A), 0.92 for CLIP (0-1) and 0.94 for Okuda (stage I) compared with AUCs of 0.56, 0.58 and 0.64 for AFP. No significant difference was found between AUC in the estimation and the validation groups. CONCLUSION: This model may enhance early-stage HCC detection and help to overcome insufficient sensitivity of AFP.

Diagnosis of Hepatitis C Virus Infection Using a Novel Mouse Monoclonal Antibody to Detect Serum HCV E1/E2 Antigens.

BACKGROUND: Hepatitis C virus (HCV) is a major cause of liver disease worldwide and in Egypt. The aim of this study was to detect HCV E1/E2 antigens using a novel mouse monoclonal antibody (mAb) designated (7G9) as a diagnostic and alternative approach for HCV detection. METHODS: The detection of HCV-E1/E2 antigens in 138 patients positive for HCV infection tested by RT-PCR and 25 healthy individuals negative for HCV as control group was done by an optimized in-house ELISA and DotELISA (based on the molecular mimicry of E2 to immunoglobulins). RESULTS: The mAb (7G9) was found to be IgM (heavy-chain)/kappa (light-chain) and characterization by western blot revealed two bands at 63 kDa for E2 and 31 kDa for E1. ELISA peptide mapping showed high reactivity with peptide derived from HCV E1 (a.a. 315 - 323) and low reactivity to peptides derived from HCV E2 (a.a. 517 - 531) and HCV E2 (a.a. 412 - 419). The mAb (7G9) showed no reactivity with HBV Ag, S. typhi or B. Abortus Ag proving high specificity. AUC for HCV-E1/E2 detection was 0.96 for all HCV patients with sensitivity 87% (119/137), specificity 88% (22/25) and efficiency 87%. The HCV-E1/E2 antigens detection by Dot-ELISA showed 76.8% sensitivity, 88% specificity and the efficiency of the assay was 78.5%. Furthermore, no correlation was found between serum HCV viral load and HCV E1/E2 antigens detection. CONCLUSIONS: The ELISA and Dot-ELISA based on the monoclonal antibody (7G9) are reliable, rapid, easy and economic diagnostic assays for HCV infection.

Level of Human Antibodies Targeting HCV E1/E2 Peptides and Spontaneous Clearance of HCV in Blood Donors.

BACKGROUND: Hepatitis C virus (HCV) is a major health problem worldwide particularly in Egypt. The humoral immune response has an important function in the control of HCV infection. The aim of this study was to investigate the role of neutralizing antibodies in Hepatitis C Virus (HCV) clearance in infected individuals. METHODS: This study was carried out on apparently healthy blood donors (n = 200). Detectable HCV antibodies were assessed by commercial ELISA and specific human immunoglobulins targeting peptides derived from HCV E1/E2 glycoproteins were measured in donors' blood using an in house optimized ELISA. Human IgG purification was carried out from positive HCV RNA and negative HCV RNA samples in order to evaluate its neutralizing activity in vitro using Huh 7 cells. RESULTS: The studied cohort included 96/200 subjects who tested positive for HCV antibodies, among which 56/96 (58%) samples were positive for HCV RNA (Group 1) and 40/96 (42%) samples had undetectable HCV RNA (Group 2). ELISA results showed that Human HCV immunoglobulin (HHI) targeting HCV E1 synthetic peptide (a.a. 315 - 323) was detectable in 63/96 (66%) and HHI targeting HCV E2 (a.a. 412 - 419) tested positive in 14/96 (15%) while 19/96 (20%) were positive for HCV E2 (a.a. 517 - 531). HHI higher than the cutoff level against peptide HCV E1 (a.a. 315 - 323) was detected in 22/63 (35%) in Group 2 and positive in 41/63 (65%) in Group 1. HHI against peptide HCV E2 (a.a. 412 - 419) was positive in 7 (50%) blood donors in Group 2 and also positive in 7 (50%) of Group 1. While HHI targeting HCV E2 (a.a. 517 - 531) was positive in 11 (60%) in Group 2 compared with 8 cases (40%) in Group 1. Purified human antibodies from cases positive for HCV antibodies and negative for HCV RNA showed in vitro neutralization at concentrations 30 and 10 µg/mL while the same concentration of purified human IgG from cases positive for HCV RNA showed no viral neutralization. CONCLUSIONS: The tested epitope(s) derived from HCV envelope E1 and E2 are important for viral clearance and hence can be used for HCV vaccine development.

Alteration of the Total Nuclear DNA Ploidy in Different Histopathological Liver Tissues Negative and Positive for HCV RNA.

BACKGROUND: Hepatitis C virus (HCV) infection is associated with the development of hepatocellular carcinoma (HCC). The molecular mechanisms of HCV-associated carcinogenesis are unknown. We aim to investigate the alteration of the total nuclear DNA content (ploidy) in different histopathological liver tissues infected with HCV and their relation to the seropositivity of HCV RNA. METHODS: Blood and liver tissues were collected from 26 patients. Diagnosis was carried out according to clinical and pathological examinations by specialized physicians. HCV RNA was detected in patients' sera and tissue samples by RT-PCR. To examine nuclear DNA ploidy, liver tissues were stained with blue Fulgen using the image analysis techniques. Finally, the patients' DNA content was examined by histochemical analysis depending on the optical density of DNA from liver biopsies using the grey image menu in each specimen. RESULTS: The HCV RT-PCR results demonstrated that 13/26 (50%) patients had detectable HCV RNA in their sera samples while 18/26 (69%) had detectable HCV RNA in liver tissues. The DNA content from those patients measured by image cytometry showed a high level of alteration of nuclear DNA ploidy and proliferation in liver tissues with HCC, less alteration of nuclear DNA ploidy in cirrhotic patients, and least proliferation nearly normal in liver fibrosis patients. Moreover, the results of histochemical analysis confirmed the DNA image cytometry results and showed that positive HCV RNA liver tissues had more DNA ploidy than negative HCV RNA liver tissues with statistical significance (p-value < 0.05). CONCLUSIONS: HCV positive liver tissue had alterations in DNA content (ploidy) which may lead to liver disease progression, malignant transformation of the liver cells and development of hepatocellular carcinoma.

In vitro neutralization of HCV by goat antibodies against peptides encompassing regions downstream of HVR-1 of E2 glycoprotein.

This article aims at testing several in vitro systems with various viral sources and cell lines for propagation of HCV to evaluate goat antibodies raised against three E2 epitopes in viral neutralization experiments. Four human cell lines (Huh-7, Huh-7.5, HepG2, and CaCo2) were tested using two different HCV viral sources; Genotype 4 infected sera and J6/JFH HCV cc particles. Neutralization capacity of goat Abs against conserved E2 epitopes; p412 (a.a 412-419), p517 (a.a 517-531), and p430 (a.a 430-447) were examined in the above mentioned in vitro systems. Although infection with patients' sera seems to mimic the in vitro situation, it has limited replication rates as compared with HCV cc particularly in Huh7.5 cells. Non-HCV adapted Huh-7 cells were also found susceptible for transfection with J6/JFH virus but at much slower kinetics. The results of the neutralization assay showed that anti p412 and anti p517 were highly neutralizing to HCVcc. Our data demonstrate that antibodies directed against the viral surface glycoprotein E2 reduced the infectivity of the J6/JFH virus and are promising agents for immunotherapy and HCV vaccine development.

Mouse monoclonal antibody towards e1 specific epitope blocks viral entry and intracellular viral replication in vitro.

We characterized viral neutralization by a murine monoclonal antibody (mAb315) developed against conserved E1 specific epitope aa 315-323 at pre- and post-binding steps of infection into Huh7 cells. Detection of native virus in infected Huh7 cells by mAb315 were demonstrated by immunostaining. Inhibitions of viral entry by three different concentrations of mAb315 were measured by intracellular amplification of HCV RNA post infection. HCV RNA positive sera from 24 patients were used to infect Huh7 cell line in absence or presence of mouse monoclonal antibody produced in Balb/c mice or culture supernatant of mouse hybrid cells. Monoclonal Ab mAb315 could detect synthetic peptide p315 adsorbed on peripheral human lymphocytes by flow cytometry and showed high immuno reactivity to E1 viral antigen in infected Huh7 cells by immunostaining. Antibody-mediated neutralization assays demonstrated the ability of mAb315 to block HCV binding/entry to target cells at 0.73 mg/mL ascitic fluid or 250 µg/mL culture supernatant of mouse hybrid cells. Sixteen of 24 infected sera could infect Huh7 cells (67%). Binding/entry of HCV was completely blocked by mAb315 in 11/16 cases (69%). These findings suggest that mAb315 can induce HCV neutralization in vitro, which makes it a candidate for developing HCV therapeutic antibodies.

Molecular Biomarkers and Signaling Pathways of Cancer Stem Cells in Colorectal Cancer.

Colorectal cancer (CRC) is the third most frequently found cancer in the world, and it is frequently discovered when it is already far along in its development. About 20% of cases of CRC are metastatic and incurable. There is more and more evidence that colorectal cancer stem cells (CCSCs), which are in charge of tumor growth, recurrence, and resistance to treatment, are what make CRC so different. Because we know more about stem cell biology, we quickly learned about the molecular processes and possible cross-talk between signaling pathways that affect the balance of cells in the gut and cancer. Wnt, Notch, TGF-ß, and Hedgehog are examples of signaling pathway members whose genes may change to produce CCSCs. These genes control self-renewal and pluripotency in SCs and then decide the function and phenotype of CCSCs. However, in terms of their ability to create tumors and susceptibility to chemotherapeutic drugs, CSCs differ from normal stem cells and the bulk of tumor cells. This may be the reason for the higher rate of cancer recurrence in patients who underwent both surgery and chemotherapy treatment. Scientists have found that a group of uncontrolled miRNAs related to CCSCs affect stemness properties. These miRNAs control CCSC functions like changing the expression of cell cycle genes, metastasis, and drug resistance mechanisms. CCSC-related miRNAs mostly control signal pathways that are known to be important for CCSC biology. The biomarkers (CD markers and miRNA) for CCSCs and their diagnostic roles are the main topics of this review study.

Development and characterization of three novel mouse monoclonal antibodies targeting spike protein S1 subunit of Middle East respiratory syndrome corona virus.

BACKGROUND: Middle East Respiratory Syndrome Coronavirus is a highly pathogenic virus that poses a significant threat to public health. OBJECTIVE: The purpose of this study is to develop and characterize novel mouse monoclonal antibodies targeting the spike protein S1 subunit of the Middle East Respiratory Syndrome Corona Virus (MERS-CoV). METHODS: In this study, three mouse monoclonal antibodies (mAbs) against MERS-CoV were generated and characterized using hybridoma technology. The mAbs were evaluated for their reactivity and neutralization activity. The mAbs were generated through hybridoma technology by the fusion of myeloma cells and spleen cells from MERS-CoV-S1 immunized mice. The resulting hybridomas were screened for antibody production using enzyme-linked immunosorbent assays (ELISA). RESULTS: ELISA results demonstrated that all three mAbs exhibited strong reactivity against the MERS-CoV S1-antigen. Similarly, dot-ELISA revealed their ability to specifically recognize viral components, indicating their potential for diagnostic applications. Under non-denaturing conditions, Western blot showed the mAbs to have robust reactivity against a specific band at 116 KDa, corresponding to a putative MERS-CoV S1-antigen. However, no reactive bands were observed under denaturing conditions, suggesting that the antibodies recognize conformational epitopes. The neutralization assay showed no in vitro reactivity against MERS-CoV. CONCLUSION: This study successfully generated three mouse monoclonal antibodies against MERS-CoV using hybridoma technology. The antibodies exhibited strong reactivity against MERS-CoV antigens using ELISA and dot ELISA assays. Taken together, these findings highlight the significance of these mAbs for potential use as valuable tools for MERS-CoV research and diagnosis (community and field-based surveillance and viral antigen detection).

Monoclonal IgY antibodies: advancements and limitations for immunodiagnosis and immunotherapy applications.

Due to their high specificity and scalability, Monoclonal IgY antibodies have emerged as a valuable alternative to traditional polyclonal IgY antibodies. This abstract provides an overview of the production and purification methods of monoclonal IgY antibodies, highlights their advantages over polyclonal IgY antibodies, and discusses their recent applications. Monoclonal recombinant IgY antibodies, in contrast to polyclonal IgY antibodies, offer several benefits. such as derived from a single B-cell clone, monoclonal antibodies exhibit superior specificity, ensuring consistent and reliable results. Furthermore, it explores the suitability of monoclonal IgY antibodies for low- and middle-income countries, considering their cost-effectiveness and accessibility. We also discussed future directions and challenges in using polyclonal IgY and monoclonal IgY antibodies. In conclusion, monoclonal IgY antibodies offer substantial advantages over polyclonal IgY antibodies regarding specificity, scalability, and consistent performance. Their recent applications in diagnostics, therapeutics, and research highlight their versatility.

Chicken egg yolk antibodies (IgY) and monoclonal antibodies: advancements and limitations for immunodiagnosis and immunotherapy applications Chicken egg yolk antibodies (IgY antibodies) and monoclonal antibodies (mAbs) are two types of antibodies used in medical applications. IgY antibodies are cost-effective, stable, and specific, with the advantage of not triggering harmful immune responses. However, they may have limitations in identifying certain target areas and availability. On the other hand, mAbs are highly specific and can detect multiple target areas on antigens, but their production is expensive and may cause immune responses. Despite these drawbacks, both IgY antibodies and mAbs show promise in various applications such as infectious disease diagnosis, cancer treatment, and autoimmune disorders. Ongoing developments in antibody technology are likely to expand their applications in immunology. This review provides an overview of the strengths and limitations of IgY antibodies and mAbs in immunodiagnosis and immunotherapy, as well as their role in pandemic control.

Recent Advances in Protective Vaccines against Hepatitis Viruses: A Narrative Review.

Vaccination has been confirmed to be the safest and, sometimes, the only tool of defense against threats from infectious diseases. The successful history of vaccination is evident in the control of serious viral infections, such as smallpox and polio. Viruses that infect human livers are known as hepatitis viruses and are classified into five major types from A to E, alphabetically. Although infection with hepatitis A virus (HAV) is known to be self-resolving after rest and symptomatic treatment, there were 7134 deaths from HAV worldwide in 2016. In 2019, hepatitis B virus (HBV) and hepatitis C virus (HCV) resulted in an estimated 820,000 and 290,000 deaths, respectively. Hepatitis delta virus (HDV) is a satellite virus that depends on HBV for producing its infectious particles in order to spread. The combination of HDV and HBV infection is considered the most severe form of chronic viral hepatitis. Hepatitis E virus (HEV) is another orally transmitted virus, common in low- and middle-income countries. In 2015, it caused 44,000 deaths worldwide. Safe and effective vaccines are already available to prevent hepatitis A and B. Here, we review the recent advances in protective vaccines against the five major hepatitis viruses.

Noninvasive Fibrosis Assessment in Chronic Hepatitis C Infection: An Update.

Liver biopsy is historically the gold standard for liver fibrosis assessment of chronic hepatitis C patients. However, with the introduction and validation of noninvasive tests (NITs) to evaluate advanced fibrosis, and the direct-acting antiviral agents for treatment of chronic hepatitis C virus (HCV), the role of NITs have become even more complex. There is now need for longitudinal monitoring and elucidation of cutoff values for prediction of liver-related complication after sustained virological response. The aim of this report is to provide a critical overview of the various NITs available for the assessment of liver fibrosis in HCV patients.

Future Prospects, Approaches, and the Government's Role in the Development of a Hepatitis C Virus Vaccine.

Developing a safe and effective vaccine against the hepatitis C virus (HCV) remains a top priority for global health. Despite recent advances in antiviral therapies, the high cost and limited accessibility of these treatments impede their widespread application, particularly in resource-limited settings. Therefore, the development of the HCV vaccine remains a necessity. This review article analyzes the current technologies, future prospects, strategies, HCV genomic targets, and the governmental role in HCV vaccine development. We discuss the current epidemiological landscape of HCV infection and the potential of HCV structural and non-structural protein antigens as vaccine targets. In addition, the involvement of government agencies and policymakers in supporting and facilitating the development of HCV vaccines is emphasized. We explore how vaccine development regulatory channels and frameworks affect research goals, funding, and public health policy. The significance of international and public-private partnerships in accelerating the development of an HCV vaccine is examined. Finally, the future directions for developing an HCV vaccine are discussed. In conclusion, the review highlights the urgent need for a preventive vaccine to fight the global HCV disease and the significance of collaborative efforts between scientists, politicians, and public health organizations to reach this important public health goal.

Biomarkers for Hepatocellular Carcinoma: From Origin to Clinical Diagnosis.

The incidence of hepatocellular carcinoma (HCC) and HCC-related deaths has increased over the last few decades. There are several risk factors of HCC such as viral hepatitis (B, C), cirrhosis, tobacco and alcohol use, aflatoxin-contaminated food, pesticides, diabetes, obesity, nonalcoholic fatty liver disease (NAFLD), and metabolic and genetic diseases. Diagnosis of HCC is based on different methods such as imaging ultrasonography (US), multiphasic enhanced computed tomography (CT), magnetic resonance imaging (MRI), and several diagnostic biomarkers. In this review, we examine the epidemiology of HCC worldwide and in Egypt as well as risk factors associated with the development of HCC and, finally, provide the updated diagnostic biomarkers for the diagnosis of HCC, particularly in the early stages of HCC. Several biomarkers are considered to diagnose HCC, including downregulated or upregulated protein markers secreted during HCC development, circulating nucleic acids or cells, metabolites, and the promising, recently identified biomarkers based on quantitative proteomics through the isobaric tags for relative and absolute quantitation (iTRAQ). In addition, a diagnostic model used to improve the sensitivity of combined biomarkers for the diagnosis of early HCC is discussed.

Mechanistic-Based Classification of Endocytosis-Related Inhibitors: Does It Aid in Assigning Drugs against SARS-CoV-2?

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) canonically utilizes clathrin-mediated endocytosis (CME) and several other endocytic mechanisms to invade airway epithelial cells. Endocytic inhibitors, particularly those targeting CME-related proteins, have been identified as promising antiviral drugs. Currently, these inhibitors are ambiguously classified as chemical, pharmaceutical, or natural inhibitors. However, their varying mechanisms may suggest a more realistic classification system. Herein, we present a new mechanistic-based classification of endocytosis inhibitors, in which they are segregated among four distinct classes including: (i) inhibitors that disrupt endocytosis-related protein-protein interactions, and assembly or dissociation of complexes; (ii) inhibitors of large dynamin GTPase and/or kinase/phosphatase activities associated with endocytosis; (iii) inhibitors that modulate the structure of subcellular components, especially the plasma membrane, and actin; and (iv) inhibitors that cause physiological or metabolic alterations in the endocytosis niche. Excluding antiviral drugs designed to halt SARS-CoV-2 replication, other drugs, either FDA-approved or suggested through basic research, could be systematically assigned to one of these classes. We observed that many anti-SARS-CoV-2 drugs could be included either in class III or IV as they interfere with the structural or physiological integrity of subcellular components, respectively. This perspective may contribute to our understanding of the relative efficacy of endocytosis-related inhibitors and support the optimization of their individual or combined antiviral potential against SARS-CoV-2. However, their selectivity, combined effects, and possible interactions with non-endocytic cellular targets need more clarification.

Assessment of specific human antibodies against SARS-CoV-2 receptor binding domain by rapid in-house ELISA.

BACKGROUND: The recently emerged SARS-CoV-2 caused a global pandemic since the last two years. The urgent need to control the spread of the virus and rapid application of the suitable health measures raised the importance of available, rapid, and accurate diagnostic approaches. OBJECTIVE: The purpose of this study is to describe a rapid in-house optimized ELISA based on the expression of the receptor binding domain (RBD) of the SARS-CoV-2 spike protein in a prokaryotic system. METHODS: We show the expression of the 30 kDa recombinant SARS-CoV-2 RBD-6×His in four different E. coli strains (at 28∘C using 0.25mM IPTG) including the expression strain E. coli BL21 (DE3) Rosetta Gami. SARS-CoV-2 rRBD-6×His protein was purified, refolded, and used as an antigen coat to assess antibody response in human sera against SARS-CoV-2 infection. RESULTS: The assessment was carried out using a total of 155 human sero-positive and negative SARS-CoV-2 antibodies. The ELISA showed 69.5% sensitivity, 88% specificity, 78.5% agreement, a positive predictive value (PPV) of 92.3%, and a negative predictive value of 56.5%. Moreover, the optical density (OD) values of positive samples significantly correlated with the commercial kit titers. CONCLUSIONS: Specific human antibodies against SARS-CoV-2 spike protein were detected by rapid in-house ELISA in sera of human COVID-19-infected patients. The availability of this in-house ELISA protocol would be valuable for various diagnostic and epidemiological applications, particularly in developing countries. Future studies are planned for the use of the generated SARS-CoV-2 rRBD-6×His protein in vaccine development and other diagnostic applications.

Neutralizing activities of caprine antibodies towards conserved regions of the HCV envelope glycoprotein E2.

Anti HCV vaccine is not currently available and the present antiviral therapies fail to cure approximately half of the treated HCV patients. This study was designed to assess the immunogenic properties of genetically conserved peptides derived from the C-terminal region of HVR-1 and test their neutralizing activities in a step towards developing therapeutic and/or prophylactic immunogens against HCV infection. Antibodies were generated by vaccination of goats with synthetic peptides derived from HCV E2. Viral neutralizing capacity of the generated anti E2 antibodies was tested using in vitro assays. Goats immunized with E2 synthetic peptides termed p412 [a.a 412-419], p430 [a.a 430-447] and p517 [a.a 517-531] generated high titers of antibody responses 2 to 4.5 fold higher than comparable titers of antibodies to the same epitopes in chronic HCV patients. In post infection experiments of native HCV into cultured Huh7.5 cells anti p412 and anti p 517 were proven to be neutralizing to HCV genotype 4a from patients' sera (87.5% and 75% respectively). On the contrary anti p430 exhibited weak viral neutralization capacity on the same samples (31.25%). Furthermore Ab mixes containing anti p430 exhibited reduced viral neutralization properties. From these experiments one could predict that neutralization by Abs towards different E2-epitopes varies considerably and success in the enrichment of neutralization epitope-specific antibodies may be accompanied by favorable results in combating HCV infection. Also, E2 conserved peptides p517 and p412 represent potential components of a candidate peptide vaccine against HCV infection.

Human cytomegalovirus infection inhibits response of chronic hepatitis-C-virus-infected patients to interferon-based therapy.

BACKGROUND AND AIM: Cytomegalovirus (CMV) is a ubiquitous pathogen that infects the majority of humans. Co-infection of CMV and hepatitis C virus (HCV) may deteriorate the prognosis of HCV-infected patients. This study was conducted to examine the role of CMV reactivation in determining the response rate to treatment with interferon and ribavirin therapy in chronic HCV patients. METHODS: Viral loads and genotyping were assessed using reverse transcription polymerase chain reaction and Innolipa systems, respectively. Reactivation of CMV in HCV patients who were all positive for CMV immunoglobulin G antibodies was tested by amplification of the gB1 gene using the end-point dilution quantitative-nested polymerase chain reaction method. RESULTS: CMV DNA was detected in 89.7% of non-responders and in 34.6% of sustained virological responders. Patients with reactivated CMV had significantly higher fibrosis scores (72.7%) than those with undetectable CMV DNA (23.8%, P=0.002). Patients with positive CMV had higher rates of non-response and relapse (79.5%) than those with negative CMV DNA (19%). Chronic HCV patients with latent CMV had higher rates of response (81%) to treatment than those with reactivated CMV (20.5%, P<0.001). Therefore, HCV patients with reactivated CMV and advanced fibrosis were least likely to achieve a sustained virological response following interferon therapy. This possibility is reduced to 50% of its original value in patients with reactivated CMV without fibrosis. CONCLUSIONS: Besides the staging of liver fibrosis, CMV co-infection should be considered as an extremely important factor when designing predictive models for HCV response to interferon treatment.

Single nucleotide polymorphism at exon 7 splice acceptor site of OAS1 gene determines response of hepatitis C virus patients to interferon therapy.

BACKGROUND AND AIM: Response to interferon therapy and disease progression in hepatitis C virus (HCV) infected patients differs among individuals, suggesting a possibility of a contribution of host genetic factors. 2'-5'-oligoadenylate synthetase 1 (OAS1), an important component of the innate immune system with a proven antiviral function, may therefore have a relationship with the response to interferon therapy and clinical course of HCV disease. Our aim was to determine the frequency of single nucleotide polymorphism (SNP) at exon 7 splice acceptor site (SAS) of the OAS1 gene in relation to the interferon response and status of HCV infection. METHODS: A 203 bp fragment containing exon 7 SAS was amplified in 70 HCV chronic patients and 50 healthy controls. SNP was examined using restriction fragment length polymorphism (RFLP) genotyping method. Correlations of SNP genotypes with response to interferon and clinical status of patients were statistically analyzed. RESULTS: There was an increasing trend of response from AA to AG to GG genotypes (P = 0.007). Genotype AA was associated with non-response to interferon and higher degree of liver fibrosis (P = 0.05). Multivariate analysis showed this SNP as independent and a significant determinant of the outcome of interferon therapy (odds ratio 4.913 [95% confidence interval 1.365-8.2], P = 0.006). CONCLUSIONS: This is the first study to show a significant association between the functional SNP at exon 7 SAS of OAS1 gene and the viral response to interferon in chronic HCV patients. Patients with AA genotype were associated with progressive HCV disease and viral resistance to interferon therapy. This OAS SNP is a potential bio-marker to predict IFN response in chronic hepatitis C patients.

A review of monoclonal antibodies in COVID-19: Role in immunotherapy, vaccine development and viral detection.

The harmful COVID-19 pandemic caused by the SARS-CoV-2 coronavirus imposes the scientific community to develop or find conventional curative drugs, protective vaccines, or passive immune strategies rapidly and efficiently. Passive immunity is based on recovering hyper-immune plasma from convalescent patients, or monoclonal antibodies with elevated titer of neutralizing antibodies with high antiviral activity, that have potential for both treatment and prevention. In this review, we focused on researching the potentiality of monoclonal antibodies for the prevention and treatment of COVID-19 infection. Our research review includes antibody-based immunotherapy, using human monoclonal antibodies targeting SARS-CoV-2 viral protein regions, specifically the spike protein regions, and using hyper-immune plasma from convalescent COVID-19 patients, in which monoclonal antibodies act as immunotherapy for the cytokine storm syndrome associated with the COVID-19 infection. In addition, we will demonstrate the role of the monoclonal antibodies in the development of candidate vaccines for SARS-CoV-2. Moreover, the recent progress of the diagnostic mouse monoclonal antibodies' role will be highlighted, as an accurate and rapid diagnostic assay, in the antigen detection of SARS-CoV-2. In brief, the monoclonal antibodies are the potential counter measures that may control SARS-CoV-2, which causes COVID-19 disease, through immunotherapy and vaccine development, as well as viral detection.