Virus Glycoprotein Research Articles

Hantaan virus glycoprotein Gc induces NEDD4-dependent PTEN ubiquitination and degradation to escape the restriction of autophagosomes and facilitate viral propagation.

Hantaan virus (HTNV) infection causes severe hemorrhagic fever with renal syndrome (HFRS) in humans and the infectious process can be regulated by autophagy. The phosphatase and tensin homolog (PTEN) protein has antiviral effects and plays a critical role in the autophagy pathway. However, the relationship between PTEN and HTNV infection is not clear and whether PTEN-regulated autophagy involves in HTNV replication is unknown. Here, we identified that HTNV infection inhibits PTEN expression invitro and invivo. The HTNV glycoprotein Gc promotes PTEN ubiquitination and degradation through 26S-proteasome pathway via the E3 ubiquitin ligase NEDD4. In addition, knockdown of PTEN prevents autophagy and increases HTNV production, while overexpression of PTEN induces autophagosome formation which can wrap HTNV particles, thus leading to restrain the production of progeny viruses. Altogether, our findings reveal the role of PTEN in HTNV infection by autophagy, highlighting the potential importance of PTEN and autophagy in the treatment of HFRS diseases.

Development and evaluation of a recombinant monoclonal human antibody with virus-neutralizing activity against the F glycoprotein of respiratory syncytial virus

Introduction. Respiratory syncytial virus (RSV) is the most common pathogen causing lower respiratory tract infections in children. RSV also poses a serious threat to the elderly and immunocompromised patients. Developing a therapy based on recombinant human antibodies to block the RSV fusion (F) glycoprotein is urgent to reduce the incidence of RSV infections and prevent associated complications. Aim. To design plasmid vectors for efficient production of the recombinant monoclonal antibody FM1 in a eukaryotic expression system targeting the RSV fusion (F) glycoprotein and to evaluate its activity against RSV subtypes A and B in vitro. Materials and methods. Constructs encoding the recombinant antibody FM1 were designed using genetic engineering. Recombinant antibodies were produced in the CHO-K1 cell line through transient expression. Antibody specimens were purified from the culture supernatant using affinity chromatography, with a modified protein A as the ligand. The virus-neutralizing activity of the antibody was evaluated in a microneutralization assay using several RSV strains on a Vero cell monolayer culture. Results. We developed a two-plasmid vector system to produce the recombinant FM1 antibody targeting the RSV F glycoprotein, using CHO cells as transient producers. The antibody was successfully produced, purified, and characterized, with its biological activity confirmed. The FM1 antibody demonstrated enhanced virus-neutralizing activity against reference and seasonal RSV strains of subtypes A and B compared to the control drug palivizumab. Conclusion. A recombinant FM1 antibody-based drug could address the import substitution challenge for protective measures against RSV infection. The authors are currently developing a stable FM1 producer clone with high productivity and viability and investigating the therapeutic efficacy of this antibody in a sublethal RSV infection mouse model.

Genetic variations and clinical significance in young-onset nasopharyngeal cancer: Analysis of EBV interaction with cellular receptor variants and viral glycoproteins.

Nasopharyngeal cancer (NPC), although rare in young individuals worldwide, is significantly influenced by the Epstein-Barr virus (EBV). Considering EBV's widespread prevalence, understanding its role in NPC's future occurrence, disease progression, clinical symptoms, metastatic tendencies, and prognosis is crucial. In this study, we extensively analyzed two young patients with NPC, who displayed distinct clinical features. We utilized Whole Exome Sequencing (WES), concentrating on EBV-interacting receptors, and applied advanced in silico methods for a deeper investigation. These methods included structural analysis via SWISS-MODEL, stability assessments using PremPS, and molecular docking studies with ClusPro. Our focus was to analyze genetic variants identified by WES and confirm EBV presence using RT-qPCR. Our comparative study between the two subjects showed that the first had milder symptoms and a lower metastasis than the second. In the first subject, we identified unique genetic variants: NRP1 c.536T>C (p.Val179Ala) and MYH9 c.4876A>G (p.Ile1626Val). Notably, the NRP1 p.Val179Ala variant caused structural changes leading to protein instability. Molecular docking suggested that this variant enhances interaction more than the wild-type. RT-qPCR validation of EBV showed lower levels in subject one (mutant-NRP1) compared to subject two (wild-type-NRP1). This finding implies that the p.Val179Ala variant in subject one could obstruct EBV entry, possibly leading to less severe clinical symptoms Our research provides new insights into the genetic factors influencing the clinical presentation of NPC, identifying promising targets for further research and therapeutic interventions. However, additional validation in a larger cohort is required to elucidate the broader impact of these genetic variants.

Cryogenic Electron Microscopy of Rift Valley Fever Virus.

Rift Valley fever virus (RVFV) is an important livestock and human pathogen. It is also a potential bioweapon owing to its ability to spread by aerosols. It is an enveloped virus containing surface protrusions composed of two viral glycoproteins, Gc and Gn; the viral core contains ribonucleoprotein complexes. We describe the use of cryogenic electron microscopy (Cryo-EM) of single particles to visualize the three-dimensional (3D) organization of RVFV. The spherical RVFV virions have a diameter of 100nm with icosahedral symmetry (T=12) and 720 prominent protrusions on their surface.In this chapter we describe the general protocols to prepare virus suspensions for Cryo-EM, image acquisition of virus particles embedded in vitreous water, and their image processing. Because of RVFV being classified as a BSL3 and potentially as a select agent, we also describe the protocol of performing Cryo-EM grid preparation and imaging in our Cryo-EM BSL3 containment, along with the general etiquette of using BSL3 containment for research, including entry into containment, dressing up for work there, manipulation with the agent, grid preparation, transfer of the frozen grids into a microscope, etc., waste disposal, and finally exit from the containment. The microscope decontamination with ClO2 is briefly described as well because that technique is not widely used in the Cryo-EM field.

Ajwa date extract (Phoenix dactylifera L.): Phytochemical analysis, antiviral activity against herpes simplex virus-I and coxsackie B4 virus, and in silico study.

To investigate the phytochemical composition of Ajwa date extract and evaluate its antiviral activity and mechanism of action. High perfomance liquid chromatography, gas chromatography-mass spectrometry, and liquid chromatography-mass spectrometry were used to analyze the phytochemical profile of Ajwa date extract. The antiviral activity was assessed using the MTT colorimetric assay against herpes simplex virus type I (HSV-I) and coxsackievirus B4 (CVB-4). Assessment of the mechanism of action against HSV-I was carried out using 3 protocols. Molecular docking and quantum chemical calculations were carried out to predict the binding affinities of the identified compounds to viral glycoprotein D. A total of 17 metabolites belonging to different classes of metabolites, mainly flavonoids, phenolic acid derivatives, fatty acids, and sugar derivatives. Ajwa extract exhibited antiviral activity against HSV-I with an IC: 50 of 113.99±4.67 μg/mL, whereas it showed limited activity against CVB-4. The antiviral activity of Ajwa extract was mainly attributed to its cell protectant activity by preventing adherence of viral to host cell with an IC: 50 equal to 57.82±1.37μg/mL. Molecular docking studies indicated that chlorogenic acid had the strongest binding affinity to viral glycoprotein D, which suggests its potential role in inhibiting viral entry into host cells. The Ajwa date extract demonstrated promising antiviral activity, especially against HSV-I. Integrating in vitro and in silico analyses provided valuable insights into the mechanisms of action.

Detection of Serum Antibodies Targeting the Marburg Virus Glycoprotein Using a Multiplex Immunoassay Platform.

Multiplex immunoassays allow for the simultaneous detection of antibody populations targeting multiple antigens in a very sensitive, high-throughput format. This assay has applications in seroprevalence, serodiagnosis, and vaccine assessment with greater sensitivity and dynamic range than standard ELISAs (enzyme-linked immunosorbent assays). Here, we show in detail the methods for multiplex immunoassays to detect IgG to the Marburg virus glycoprotein.

Vector induced humoral responses after rVSVΔG-ZEBOV-GP immunization identify vaccinated individuals and correlate with Ebola virus glycoprotein antibodies

Abstract Background The robustness and persistence of vaccine antigen-induced antibodies are often used as proxy indicators of vaccine efficacy, but immune responses to vaccine vectors are typically less well-defined. Our study considered the kinetics of immunoglobulin (IgG) responses against the vector (vesicular stomatitis Indiana virus [VSIV]) nucleoprotein (N) and the inserted antigen (Ebola virus [EBOV]) glycoprotein (GP1,2) components of the rVSVΔG-ZEBOV-GP (rVSV-ZEBOV) vaccine and evaluated their use as biomarkers to confirm self-reported vaccination status. Methods From the Partnership for Research on Ebola Virus in Liberia (PREVAIL) I clinical trial (NCT02344407), we randomly selected 212 participants who received rVSV-ZEBOV (n=107) or placebo (n=105). Levels of IgG antibodies to EBOV GP1,2 or VSIV N were measured using the Filovirus Animal Non-Clinical Group (FANG) ELISA and a newly developed single-molecule array (Simoa) immunoassay, respectively. Results Anti-EBOV GP1,2 IgG and anti-VSIV N IgG were first detected 10–14 d post-vaccination, further increased at 28 d, and remained stable through 360 d. Antibody titers were significantly higher in women compared to men. Anti-EBOV GP1,2 and anti-VSIV N IgG titers were significantly correlated (p<0.001) at 28 d (r=0.47), 180 d (r=0.45), and 360 d (r=0.59). At 28 d, the area under the curve (AUC) of receiver operating characteristic (ROC) curves discriminated vaccinated from unvaccinated patients with high accuracy (AUC=0.965 for anti-VSIV N IgG; AUC=0.945 for anti-EBOV GP1,2 IgG [p<0.001]). Conclusions We report a reliable assay to measure vector-induced humoral responses after rVSV-ZEBOV vaccination and demonstrate the assay’s utility to confirm vaccination status.

Recombinant VSV as a platform for rabies vaccine development: Enhancing immunogenicity and safety

The research investigates the possibility of development of a recombinant vesicular stomatitis virus (VSV) expressing the rabies virus glycoprotein as a novel rabies vaccine. The recombinant VSV can show robust immunogenicity, eliciting strong virus-neutralizing antibody responses in both mice and dogs. The oral vaccine formulation proved stable in simulated gastric conditions and induced immune responses comparable to intramuscular injection. Long-term immunity studies indicated high antibody levels and protection against rabies virus challenge at six months and one-year post-immunization, suggesting potential for durable immunity, particularly in dogs. Toxicity studies can be used to analyze adverse effects, confirming the vaccine’s safety. The potential for the recombinant VSV vaccine to induce mucosal immunity and spread through social behaviours in wildlife populations presents a promising approach for rabies control. However, challenges such as ensuring genetic stability and evaluating environmental impacts must be addressed. This research highlights the recombinant VSV-based vaccine’s promise as an effective, safe, and potentially self-disseminating tool for rabies prevention, with implications for both human and veterinary applications.

In vivo self-assembled siRNAs within small extracellular vesicles attenuate LRRK2-induced neurodegeneration in Parkinson's disease models.

Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene play an important role in Parkinson's disease (PD) pathogenesis, and downregulation of LRRK2 has become a promising therapy for PD. Here, we developed a synthetic biology strategy for the self-assembly and delivery of small interfering RNAs (siRNAs) of LRRK2 into the substantia nigra via small extracellular vesicles (sEVs) using a genetic circuit (in the form of naked DNA plasmid) to attenuate PD-like phenotypes in mouse model. We generated the genetic circuit encoding both a neuron-targeting rabies virus glycoprotein (RVG) tag and a LRRK2 siRNA under the control of a cytomegalovirus (CMV) promoter, and assessed its therapeutic effects using LRRK2R1441G mouse models of PD. After intravenous injection, the genetic circuit was taken up by the host liver to reprogram liver cells to produce and self-assemble LRRK2 siRNAs into sEVs, and then the sEV-enclosed LRRK2 siRNAs were further transferred by the endogenous circulating system of sEVs and guided by the RVG tag to the substantia nigra. Intravenous injection of this genetic circuit reduced total and phosphorylated LRRK2 levels in the substantia nigra, and attenuated PD-like phenotypes in two mouse models by rescuing LRRK2R1441G-induced dopaminergic neurodegeneration and reducing microgliosis. This study provides an efficient therapeutic strategy to attenuate LRRK2-induced neurodegeneration and neuroinflammation in PD mouse models, and may open a new avenue to safely deliver siRNA into brain after peripheral intravenous injection and facilitate PD treatment.

Replicating RNA vaccine confers durable immunity against Crimean Congo hemorrhagic fever virus challenge in mice

Spread by Hyalomma genus ticks, Crimean-Congo hemorrhagic fever virus (CCHFV) causes a severe hemorrhagic disease endemic throughout Southern and Eastern Europe, Asia, and Africa. To date, there are no widely approved vaccines for CCHFV and treatment for disease is largely supportive. Due to this lack of intervention, the WHO lists CCHFV as a high-priority pathogen. Recently, we described a highly efficacious self-replicating RNA vaccine which is protective against CCHFV disease in mice and non-human primates. This vaccine induces high titers of non-neutralizing anti-nucleoprotein (NP) antibodies and a robust T-cell response against the viral glycoprotein. Here, we assess the durability of this vaccine in mice by monitoring the immunogenicity and efficacy of this vaccine up to 1 year post vaccination. We found that while glycoprotein-specific T-cell responses and anti-NP antibody titers waned over time, mice remained protected against lethal CCHFV challenge for at least 1 year post vaccination.

Carbohydrate-mediated interactions between chloroviruses and the immune system

Understanding the molecular mechanisms which drive and modulate host-pathogen interactions are essential when designing effective therapeutic and diagnostic approaches aimed at controlling infectious diseases. Certain large and giant viruses have recently been discovered as components of the human virome, yet little is known about their interactions with the host immune system. We have dissected the role of viral N-linked glycans during the interaction between the glycoproteins from six chloroviruses (belonging to three chlorovirus classes: NC64A, SAG, and Osy viruses) and the representative carbohydrate-binding receptors of the innate immune system. Using solid-phase assays we have identified the binding of viral glycoproteins to different C-type lectins in a carbohydrate-dependent manner. These experiments verified the importance of D-rhamnose in modulating their binding to C-type lectins DC-SIGN and Langerin. In vitro assays further determined the ability of the chlorovirus glycoproteins to trigger secretion of cytokines Interleukins 6 and 10 (IL-6 and IL-10) in human monocyte-derived dendritic cells and mouse macrophages. Additionally, IgG from healthy human controls recognized certain chlorovirus glycoproteins, indicating the significance of human environmental viral exposures. Collectively, these results demonstrate the ability of the innate and adaptive immune systems to recognize chlorovirus glycoproteins, a process dependent on their specific N-glycan structures.

Exploring the influence of anionic lipids in the host cell membrane on viral fusion.

Membrane fusion is an essential component of the viral lifecycle that allows the delivery of the genetic information of the virus into the host cell. Specialized viral glycoproteins exist on the surface of mature virions where they facilitate fusion through significant conformational changes, ultimately bringing opposing membranes into proximity until they eventually coalesce. This process can be positively influenced by a number of specific cellular factors such as pH, enzymatic cleavage, divalent ions, and the composition of the host cell membrane. In this review, we have summarized how anionic lipids have come to be involved in viral fusion and how the endosomal resident anionic lipid BMP has become increasingly implicated as an important cofactor for those viruses that fuse via the endocytic pathway.

Standardized Eucalyptus maculata (Corymbia maculata) Resin Extract: Metabolomic Profiling, In Vitro and In Silico Study of Anti-HSV Activity.

Recent episodes of viral pandemics have led to a quest for new drugs to act on emerging targets. Most challenging viruses are only mutants of already known viruses. Here comes the role of metabolomics in investigating natural secondary metabolites as sustainable antiviral drug candidates. Resins are natural plant products having the advantage of being concentrated and consisting of precious terpenoids, phenolics, and flavonoids, known for their anti-pathogen activity. This study aimed at investigation of the major phytoconstituents in the Eucalyptus maculata (EM) resin using high resolution liquid chromatography-mass spectrometry (LC-MS/MS) and investigating its antiviral potential. In vitro screening of the standardized EM antiviral activity was performed. High resolution LC-MS/MS analysis was done for the extract followed by investigation of the possible active metabolites through molecular docking techniques against two viral protein targets; herpes simplex virus glycoprotein D (HSV gD) and B- and T-lymphocyte attenuator/herpes virus entry mediator complex. The evaluation in negative and positive modes identified 29 substances and revealed the prevalence of coumaryl and galloyl derivatives, in addition to kaempferol and aromadendrin derivatives. Antiviral in vitro screening led to the conclusion of the promising effect of the resin against HSV that was further confirmed through molecular docking. EM resin represents a future sustainable drug discovery and should be further investigated as an antiviral agent.

Evaluation of the Efficacy of the Vaccine Production Process in Removing Residual Host Cell DNA from the Vero Cell Rabies Vaccine.

The Vero cell rabies vaccine is currently the most widely used human rabies vaccine. However, owing to the presence of residual host cell DNA (HCD) in the final product and the potential tumorigenicity of the DNA of high-passage Vero cells, the WHO not only sets a limit on the number of times cells used in production can be passaged, but also imposes strict requirements on the amount of residual HCD in the final vaccine product. To systematically reduce the HCD level in the final vaccine product, multiple purification steps are included in the vaccine production process. This study investigated the effectiveness of key production steps in antigen recovery and DNA removal. The residual HCD fragment content and size distribution were detected using fluorescence quantitative PCR (qPCR) and capillary gel electrophoresis (CGE), and the rabies virus glycoprotein antigen content was detected using enzyme-linked immunosorbent assay (ELISA). The antigen recovery rate and HCD removal rate in each key process were calculated to evaluate the scientific basis and effectiveness of each production step. Additionally, the stability of the process was studied using multiple commercial batches of the product. The results revealed that the total antigen recovery rate in the production process described in this report was no less than 8.5%, and the effective removal rate of residual HCD was not lower than 99.99%. Moreover, the amount of residual HCD in the final product was far below the quality standard of 2 ng/dose, and most of the residual HCD fragments were smaller than 200 bp. The results of the process stability studies on multiple commercial batches showed that the bulk human rabies vaccine produced by this process had excellent safety and efficacy and that the production process was stable and thus suitable for large-scale batch production. The production process described in this study achieved effective recovery of viral antigens and efficient removal of residual HCD, and the process was stable and controllable, enabling the continuous and stable production of vaccine products that meet WHO recommendations and the relevant requirements of the current edition of the Chinese Pharmacopeia. In addition, this study provides theoretical guidance for optimizing the vaccine production process.

Epitope-focused immunogens targeting the hepatitis C virus glycoproteins induce broadly neutralizing antibodies.

Hepatitis C virus (HCV) infection causes ~290,000 annual human deaths despite the highly effective antiviral treatment available. Several viral immune evasion mechanisms have hampered the development of an effective vaccine against HCV, among them the remarkable conformational flexibility within neutralization epitopes in the HCV antigens. Here, we report the design of epitope-focused immunogens displaying two distinct HCV cross-neutralization epitopes. We show that these immunogens induce a pronounced, broadly neutralizing antibody response in laboratory and transgenic human antibody mice. Monoclonal human antibodies isolated from immunized human antibody mice specifically recognized the grafted epitopes and neutralized four diverse HCV strains. Our results highlight a promising strategy for developing HCV immunogens and provide an encouraging paradigm for targeting structurally flexible epitopes to improve the induction of neutralizing antibodies.

Respiratory syncytial virus glycoprotein G impedes CX3CR1-activation by CX3CL1 and monocyte function

The soluble form of the Respiratory Syncytial Virus (RSV) G protein (sG) bears resemblance to the chemokine fractalkine (CX₃CL1). Both RSV sG and CX3CL1 possess a mucin-like domain and a CX3C motif, exist in membrane-associated and soluble forms, and bind to the CX₃CR1 receptor expressed on immune and epithelial cells. To explore the biological significance of RSV sG and CX₃CR1 interaction, we produced wild type (WT) and CX₃C motif-deficient (CX3CMut) RSV sG proteins and determined their effects on CX₃CR1 signaling in monocytic cells. Both CX3CMut- and WT RSV sG failed to activate CX₃CR1 signaling directly. However, WT sG competed with CX₃CL1 for CX₃CR1 binding and reduced CX3CL1-induced CX₃CR1-activation, monocyte migration, and adhesion. The CX₃C motif of sG was crucial for competitive blocking of CX3CL1-mediated activation, as CX₃CMut sG did not affect these CX₃CR1 functions significantly. Thus, blockade of CX₃CR1 signaling by sG may allow RSV to dampen host immune responses.

Evaluation of the immune status of dogs vaccinated against rabies by an enzyme-linked immunosorbent assay using crude preparations of insect cells infected with a recombinant baculovirus encoding the rabies virus glycoprotein gene.

Evaluation of the effectiveness of vaccination of animals against rabies is not routinely implemented. In cases where it is carried out, the rapid fluorescent focus inhibition test (RFFIT) or the fluorescent antibody virus neutralization (FAVN) test are the recommended tests. However, both of these tests require handling of live rabies virus (RABV), and are cumbersome to perform. In view of this, the enzyme-linked immunosorbent assay (ELISA) has been proposed as a surrogate test; however, availability of appropriate antigen is a major impediment for the development of ELISAs to detect anti-rabies antibodies. The most widely used antigen is the RABV glycoprotein (G) purified from cell culture-propagated virus, which requires a biosafety level 3 containment. The alternative is to use recombinantly expressed G, which needs to be to be properly glycosylated and folded to serve as the best antigen. The most suitable system for its production is the baculovirus expression system (BVES). However, purification of RABV G is challenging. We therefore tested partially purified preparations in the form of extracts of insect cells infected with baculovirus expressing RABV G, against sera from vaccinated dogs in an indirect ELISA. The results showed good concordance against RFFIT, with sensitivity and specificity of 90.48% and 80.00%, respectively. The system may be used for quick screening to determine the presence and an approximate level of antibodies, and can be modified to enable monitoring of mass dog vaccination programs, as well as to facilitate certification of dogs intended for international travel and transportation.

Immune Response to an Adjuvanted Recombinant Zoster Vaccine in Japanese Patients with Rheumatoid Arthritis Receiving Upadacitinib (End Zoster-J Study): Study Protocol for an Exploratory Parallel Triple-Arm Prospective Trial.

Background: Janus kinase (JAK) inhibitors have emerged as a new class of disease-modifying anti-rheumatic drugs in the treatment of rheumatoid arthritis (RA). However, herpes zoster is one of the common adverse events of JAK inhibitors, including upadacitinib, which is especially high in Japanese patients with RA compared to those from Western countries. Recombinant zoster vaccine (Shingrix®) is an adjuvanted subunit vaccine containing varicella-zoster virus (VZV) glycoprotein E (gE) that is effective in adults over 50 years of age. Despite this, no studies have examined its immunogenicity in Japanese patients receiving upadacitinib. Therefore, this study aims to examine the effectiveness of the recombinant zoster vaccine in Japanese patients with RA receiving upadacitinib. Methods: This is a single-center, exploratory, interventional, open-label, parallel triple-arm, prospective study. A total of 69 patients (23 in each group) aged 50 years or over and treated with a stable dose of methotrexate (MTX) monotherapy (6-12 mg/week), upadacitinib monotherapy (15 mg/day), or MTX (6-12 mg/week) + upadacitinib 15 mg/day (combination) for at least 1 month prior to study entry will be included. Moreover, all three groups will receive two intramuscular injections of the recombinant zoster vaccine at 8-week intervals. The primary endpoint is the proportion of positive anti-gE antibodies 4 weeks after the second injection. Secondary endpoints include RA disease activity, positive gE-specific CD4+ T-cells, and VZV-specific antibodies at indicated time points. Data on outcome measures will be collected at baseline and at 4, 8, 12, and 20 weeks. Endpoints will be summarized using descriptive statistics from baseline therapy, and results will be compared in an exploratory manner. Discussion: Despite the limited generalizability due to its design as a single-center, single-ethnic study, small sample size, and short observation period, this study provides evidence on the effectiveness and tolerability of recombinant zoster vaccine in Japanese patients with RA receiving upadacitinib.

Distinct amino acid substitutions in the EEV glycoprotein and DNA-dependent RNA polymerase of lumpy skin disease virus identified in wetland areas of Bangladesh.

The recent outbreak of lumpy skin disease virus (LSDV) in the wetland areas of Bangladesh presents a significant concern for both animal health and regional biosecurity. Epidemiological investigations into nine major outbreaks in the wetland areas revealed distinctive clinical symptoms in affected cattle, including elevated body temperature, excessive salivation, and the presence of skin nodules. Histopathological examination unveiled larger nodules compared to previous outbreaks, along with signs of secondary infection. Molecular analysis confirmed the presence of LSDV in all samples, with subsequent sequencing revealing genetic similarities with virus isolates of Bangladesh, India, China, Russia, Serbia and Greece. Most importantly amino acid variations in the viral EEV glycoprotein and DNA-dependent RNA polymerase were revealed that also altered the structures of the respective proteins significantly suggesting potential implications for viral pathogenesis. Additionally, successful isolation of LSDV in Vero cells demonstrated cytopathic effects, supporting the potential for vaccine development. In conclusion, this study provides comprehensive insights into the epidemiology, genomic characters with altered predicted structures of two major viral proteins and pathogenesis of LSDV outbreaks in Bangladesh. These findings emphasize the critical need for ongoing monitoring and adaptive control strategies, including the development of effective vaccines, to mitigate the impact of LSDV in affected regions and safeguard regional livestock health.

U-73122, a phospholipase C inhibitor, impairs lymphocytic choriomeningitis virus virion infectivity.

Lassa virus (LASV) is an Old World (OW) mammarenavirus that causes Lassa fever, a life-threatening acute febrile disease endemic in West Africa. Lymphocytic choriomeningitis virus (LCMV) is a worldwide-distributed, prototypic OW mammarenavirus of clinical significance that has been largely neglected as a human pathogen. No licensed OW mammarenavirus vaccines are available, and the current therapeutic option is limited to the off-label use of ribavirin, which offers only partial efficacy. This situation underscores the urgent need to develop novel antivirals against human pathogenic mammarenaviruses. Previously, we showed that afatinib, a pan-ErbB tyrosine kinase inhibitor, inhibited multiple steps of the life cycles of OW LASV and LCMV, as well as the New World Junín virus vaccine strain Candid#1. In the present study, we investigated the inhibitory effect of U-73122, a phospholipase C inhibitor that acts downstream of ErbB signalling, on LCMV multiplication. U-73122 inhibited WT recombinant (r) LCMV multiplication in cultured cells. Preincubation of cell-free LCMV virions with U-73122 resulted in impaired virion infectivity. U-73122 also inhibited the infection of rLCMVs expressing heterologous viral glycoproteins, including the vesicular stomatitis Indiana virus (VSIV) glycoprotein, whereas WT VSIV infection was not affected by U-73122 treatment. Our results show the novel bioactivity of U-73122 as an LCMV inhibitor and indicate the presence of a virion-associated molecule that is necessary for virion infectivity and can be exploited as a potential antiviral drug target against human pathogenic mammarenavirus infections.