Viral Capsid Research Articles

The HIV-1 capsid serves as a nanoscale reaction vessel for reverse transcription.

The viral capsid performs critical functions during HIV-1 infection and is a validated target for antiviral therapy. Previous studies have established that the proper structure and stability of the capsid are required for efficient HIV-1 reverse transcription in target cells. Moreover, it has recently been demonstrated that permeabilized virions and purified HIV-1 cores undergo efficient reverse transcription in vitro when the capsid is stabilized by addition of the host cell metabolite inositol hexakisphosphate (IP6). However, the molecular mechanism by which the capsid promotes reverse transcription is undefined. Here we show that wild type HIV-1 virions can undergo efficient reverse transcription in vitro in the absence of a membrane-permeabilizing agent. This activity, originally termed "natural endogenous reverse transcription" (NERT), depends on expression of the viral envelope glycoprotein during virus assembly and its incorporation into virions. Truncation of the gp41 cytoplasmic tail markedly reduced NERT activity, suggesting that gp41 licenses the entry of nucleotides into virions. By contrast to reverse transcription in permeabilized virions, NERT required neither the addition of IP6 nor a mature capsid, indicating that an intact viral membrane can substitute for the function of the viral capsid during reverse transcription in vitro. Collectively, these results demonstrate that the viral capsid functions as a nanoscale container for reverse transcription during HIV-1 infection.

Ejectosome of Pectobacterium bacteriophage ΦM1.

Podophages that infect gram-negative bacteria, such as Pectobacterium pathogen ΦM1, encode tail assemblies too short to extend across the complex gram-negative cell wall. To overcome this, podophages encode a large protein complex (ejectosome) packaged inside the viral capsid and correspondingly ejected during infection to form a transient channel that spans the periplasmic space. Here, we describe the ejectosome of bacteriophage ΦM1 to a resolution of 3.32 Å by single-particle cryo-electron microscopy (cryo-EM). The core consists of tetrameric and octameric ejection proteins which form a ∼1.5-MDa ejectosome that must transition through the ∼30 Å aperture created by the short tail nozzle assembly that acts as the conduit for the passage of DNA during infection. The ejectosome forms several grooves into which coils of genomic DNA are fit before the DNA sharply turns and goes down the tunnel and into the portal. In addition, we reconstructed the icosahedral capsid and hybrid tail apparatus to resolutions between 3.04 and 3.23 Å, and note an uncommon fold adopted by the dimerized decoration proteins which further emphasize the structural diversity of podophages. These reconstructions have allowed the generation of a complete atomic model of the ΦM1, uncovering two distinct decoration proteins and highlighting the exquisite structural diversity of tailed bacteriophages.

Tanomastat exerts multi-targeted inhibitory effects on viral capsid dissociation and RNA replication in human enteroviruses

Global cyclical outbreaks of human enterovirus infections has positioned human enterovirus A71 (EV-A71) as a neurotropic virus of clinical importance. However, there remains a scarcity of internationally approved antivirals and vaccines. In pursuit of repurposing drugs for combating human enteroviruses, we employed a comprehensive pharmacophore- and molecular docking-based virtual screen targeting EV-A71 capsid protein VP1-4, 3C protease, and 3D polymerase proteins. Among 15 shortlisted ligand candidates, we dissected the inhibitory mechanism of Tanomastat in cell-based studies and evaluated its invivo efficacy in an EV-A71-infected murine model. We demonstrated that Tanomastat exerts dose-dependent inhibition on EV-A71 replication, with comparable efficacy profiles in enterovirus species A, B, C, and D invitro. Time-course studies suggested that Tanomastat predominantly disrupts early process(es) of the EV-A71 replication cycle. Mechanistically, live virus particle tracking and docking predictions revealed that Tanomastat specifically impedes viral capsid dissociation, potentially via VP1 hydrophobic pocket binding. Bypassing its inhibition on entry stages, we utilized EV-A71 replication-competent, 3Dpol replication-defective, and bicistronic IRES reporter replicons to show that Tanomastat also inhibits viral RNA replication, but not viral IRES translation. We further showed that orally administered Tanomastat achieved 85% protective therapeutic effect and alleviated clinical symptoms in EV-A71-infected neonatal mice. Our study establishes Tanomastat as a broad-spectrum anti-enterovirus candidate with promising pre-clinical efficacy, warranting further testing for potential therapeutic application. MOE Tier 2 grants (MOE-T2EP30221-0005, R571-000-068-592, R571-000-076-515, R571-000-074-733) and A∗STARBiomedical Research Council (BMRC).

Advancements in Functional Nanomaterials Inspired by Viral Particles.

Virus-like particles (VLPs) are nanostructures composed of one or more structural proteins, exhibiting stable and symmetrical structures. Their precise compositions and dimensions provide versatile opportunities for modifications, enhancing their functionality. Consequently, VLP-based nanomaterials have gained widespread adoption across diverse domains. This review focuses on three key aspects: the mechanisms of viral capsid protein self-assembly into VLPs, design methods for constructing multifunctional VLPs, and strategies for synthesizing multidimensional nanomaterials using VLPs. It provides a comprehensive overview of the advancements in virus-inspired functional nanomaterials, encompassing VLP assembly, functionalization, and the synthesis of multidimensional nanomaterials. Additionally, this review explores future directions, opportunities, and challenges in the field of VLP-based nanomaterials, aiming to shed light on potential advancements and prospects in this exciting area of research.

Medicinal Plants as Effective Antiviral Agents and Their Potential Benefits

This paper explores a diverse field of medicinal plants as potential antiviral agents, and delves into utilization of plant medicine for combating viral infections, emphasizing recent surge in research on natural products from plants as antiviral agents. Specific plant-derived compounds, like phyllanthin and iscador, have been proven to exhibit antiviral properties with great potential for pharmaceutical development. Mechanisms of antiviral action by phytochemicals that are present in medicinal plants, including direct viral inhibition, degradation of viral capsid, and immunomodulation were identified, and a combination therapy of medicinal plants with conventional antiviral drugs were explored. Efficacy of medicinal plants as antiviral agents was critically assessed and revealed that the complexity and variability of herbal formulations, and safety concerns regarding toxicity levels, pose challenges in drug development. However, research on medicinal plants is often hindered by limited understanding of phytochemical mechanisms, the complexity and variability of herbal formulations, and safety concerns regarding toxicity and interactions with other medications. The way forward in harnessing full potential of medicinal plants as antiviral agents underscores the need for further research into developing models that seek to enhance the selectivity of plant extracts in order to minimize toxicity levels.

Tumor cell membrane biomimetic liposomes-coated oncolytic viruses to target the homotypic tumor and augment the antitumor efficacy

Though oncolytic viruses (OVs) hold significant potential for comprehensive treatment of malignant tumors, their systemic administration faces substantial challenges such as insufficient circulation time, inadequate tumor targeting, and spontaneous antiviral immune response of the body, which seriously limits the clinical application of OVs. Herein, we proposed a tumor targeting strategy of tumor cell membrane biomimetic liposomes to encapsulate OVs for intravenous delivery, which enables OVs to target the homotypic tumor lesions and exert their oncolytic effect. On the one hand, this cell membrane biomimetic carrier enhanced the encapsulation of OVs by the hybrid lipid membranes, concealed the viral capsid proteins, and diminished the neutralization and clearance of the virions from the bloodstream. On the other hand, enhanced tumor targeted delivery can be achieved through the utilization of homologous adhesion molecules on the surface of tumor cell membrane. In addition, this strategy also promoted the tumor infiltration of CD4+, CD8+ T cells mediated by the oncolytic effect of OVs and increased the levels of inflammatory factors such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the tumor, thereby effectively enhancing the anti-tumor effect of intravenous administration of OVs. The findings of our study demonstrate that T-L@Ad11 offers a handy and efficient approach for targeting tumors, thereby enhancing the antitumor efficacy of intravenous administration of OVs.

Molecular and Evolutionary Characteristics of Chicken Parvovirus (ChPV) Genomes Detected in Chickens with Runting-Stunting Syndrome.

Chicken Parvovirus (ChPV) belongs to the genus Aveparvovirus and is implicated in enteric diseases like runting-stunting syndrome (RSS) in poultry. In RSS, chicken health is affected by diarrhea, depression, and increased mortality, causing significant economic losses in the poultry industry. This study aimed to characterize the ChPV genomes detected in chickens with RSS through a metagenomic approach and compare the molecular and evolutionary characteristics within the Aveparvovirus galliform1 species. The intestinal content of broiler flocks affected with RSS was submitted to viral metagenomics. The assembled prevalent genomes were identified as ChPV after sequence and phylogenetic analysis, which consistently clustered separately from Turkey Parvovirus (TuPV). The strain USP-574-A presented signs of genomic recombination. The selective pressure analysis indicated that most of the coding genes in A. galliform1 are evolving under diversifying (negative) selection. Protein modeling of ChPV and TuPV viral capsids identified high conservancy over the VP2 region. The prediction of epitopes identified several co-localized antigenic peptides from ChPV and TuPV, especially for T-cell epitopes, highlighting the immunological significance of these sites. However, most of these peptides presented host-specific variability, obeying an adaptive scenario. The results of this study show the evolutionary path of ChPV and TuPV, which are influenced by diversifying events such as genomic recombination and selective pressure, as well as by adaptation processes, and their subsequent immunological impact.

To 200,000 m/z and Beyond: Native Electron Capture Charge Reduction Mass Spectrometry Deconvolves Heterogeneous Signals in Large Biopharmaceutical Analytes.

Great progress has been made in the detection of large biomolecular analytes by native mass spectrometry; however, characterizing highly heterogeneous samples remains challenging due to the presence of many overlapping signals from complex ion distributions. Electron-capture charge reduction (ECCR), in which a protein cation captures free electrons without apparent dissociation, can separate overlapping signals by shifting the ions to lower charge states. The concomitant shift to higher m/z also facilitates the exploration of instrument upper m/z limits if large complexes are used. Here we perform native ECCR on the bacterial chaperonin GroEL and megadalton scale adeno-associated virus (AAV) capsid assemblies on a Q Exactive UHMR mass spectrometer. Charge reduction of AAV8 capsids by up to 90% pushes signals well above 100,000 m/z and enables charge state resolution and mean mass determination of these highly heterogeneous samples, even for capsids loaded with genetic cargo. With minor instrument modifications, the UHMR instrument can detect charge-reduced ion signals beyond 200,000 m/z. This work demonstrates the utility of ECCR for deconvolving heterogeneous signals in native mass spectrometry and presents the highest m/z signals ever recorded on an Orbitrap instrument, opening up the use of Orbitrap native mass spectrometry for heavier analytes than ever before.

Towards Cell-Permeable Hepatitis B Virus Core Protein Variants as Potential Antiviral Agents.

Hepatitis B virus (HBV) infection remains a major health threat with limited treatment options. One of various new antiviral strategies is based on a fusion of Staphylococcus aureus nuclease (SN) with the capsid-forming HBV core protein (HBc), termed coreSN. Through co-assembly with wild-type HBc-subunits, the fusion protein is incorporated into HBV nucleocapsids, targeting the nuclease to the encapsidated viral genome. However, coreSN expression was based on transfection of a plasmid vector. Here, we explored whether introducing protein transduction domains (PTDs) into a fluorescent coreSN model could confer cell-penetrating properties for direct protein delivery into cells. Four PTDs were inserted into two different positions of the HBc sequence, comprising the amphiphilic translocation motif (TLM) derived from the HBV surface protein PreS2 domain and three basic PTDs derived from the Tat protein of human immunodeficiency virus-1 (HIV-1), namely Tat4, NP, and NS. To directly monitor the interaction with cells, the SN in coreSN was replaced with the green fluorescent protein (GFP). The fusion proteins were expressed in E. coli, and binding to and potential uptake by human cells was examined through flow cytometry and fluorescence microscopy. The data indicate PTD-dependent interactions with the cells, with evidence of uptake in particular for the basic PTDs. Uptake was enhanced by a triplicated Simian virus 40 (SV40) large T antigen nuclear localization signal (NLS). Interestingly, the basic C terminal domain of the HBV core protein was found to function as a novel PTD. Hence, further developing cell-permeable viral capsid protein fusions appears worthwhile.

Martini 3 OliGo̅mers: A Scalable Approach for Multimers and Fibrils in GROMACS.

Martini 3 is a widely used coarse-grained simulation method for large-scale biomolecular simulations. It can be combined with a Go̅ model to realistically describe higher-order protein structures while allowing the folding and unfolding events. However, as of today, this method has largely been used only for individual monomers. In this article, we describe how the Go̅ model can be implemented within the framework of Martini 3 for a multimer system, taking into account both intramolecular and intermolecular interactions in an oligomeric protein system. We demonstrate the method by showing how it can be applied to both structural stability maintenance and assembly/disassembly of protein oligomers, using aquaporin tetramer, insulin dimer, and amyloid-β fibril as examples. We find that addition of intermolecular Go̅ potentials stabilizes the quaternary structure of proteins. The strength of the Go̅ potentials can be tuned so that the internal fluctuations of proteins match the behavior of atomistic simulation models, however, the results also show that the use of too strong intermolecular Go̅ potentials weakens the chemical specificity of oligomerization. The Martini-Go̅ model presented here enables the use of Go̅ potentials in oligomeric molecular systems in a computationally efficient and parallelizable manner, especially in the case of homopolymers, where the number of identical protein monomers is high. This paves the way for coarse-grained simulations of large protein complexes, such as viral protein capsids and prion fibrils, in complex biological environments.

High-Throughput Screening of Antiviral Compounds Using a Recombinant Hepatitis B Virus and Identification of a Possible Infection Inhibitor, Skimmianine.

We developed a novel hepatitis B virus (HBV) infection-monitoring system using a luminescent, 11-amino acid reporter (HiBiT). We performed high-throughput antiviral screening using this system to identify anti-HBV compounds. After the infection of primary human hepatocytes with the recombinant virus HiBiT-HBV, which contains HiBiT at its preS1, 1262 compounds were tested in a first screening using extracellular HiBiT activity as an indicator of viral infection. Following a second screening, we focused on the compound skimmianine, which showed a potent antiviral effect. When skimmianine was added at the same time as HiBiT-HBV infection, skimmianine inhibited HiBiT activity with EC50 of 0.36 pM, CC50 of 1.67 μM and a selectivity index (CC50:EC50 ratio) of 5,100,000. When skimmianine was added 72 h after HiBiT-HBV infection, the EC50, CC50 and selectivity index were 0.19 μM, 1.87 μM and 8.79, respectively. Time-lapse fluorescence imaging analysis using another recombinant virus, ReAsH-TC155HBV, with the insertion of tetra-cysteine within viral capsid, revealed that skimmianine inhibited the accumulation of the capsid into hepatocytes. Furthermore, skimmianine did not inhibit either attachment or internalization. These results imply that skimmianine inhibits the retrograde trafficking of the virus after internalization. This study demonstrates the usefulness of the recombinant virus, HiBiT-HBV, for high-throughput screening to identify anti-HBV compounds.

Production and evaluation of three kinds of vaccines against largemouth bass virus, and DNA vaccines show great application prospects

Largemouth bass virus (LMBV) infections has resulted in high mortality and economic losses to the global largemouth bass industry and has seriously restricted the healthy development of the bass aquaculture industry. There are currently no antiviral therapies available for the control of this disease. In this study, we developed three types of vaccine against LMBV; whole virus inactivated vaccine (I), a subunit vaccine composed of the major viral capsid protein MCP (S) as well as an MCP DNA vaccine(D), These were employed using differing immunization and booster strategies spaced 2 weeks apart as follows: II, SS, DD and DS. We found that all vaccine groups induced humoral and cellular immune responses and protected largemouth bass from a lethal LMBV challenge to varying degrees and DD produced the best overall effect. Specifically, the levels of specific IgM in serum in all immunized groups were elevated and significantly higher than those in the control group. Moreover, the expression of humoral immunity (CD4 and IgM) and cellular immunity (MHCI-α) as well as cytokines (IL-1β) was increased, and the activity of immunity-related enzymes ACP, AKP, LZM, and T-SOD in the serum was significantly enhanced. In addition, the relative percent survival of fish following an LMBV lethal challenge 4 weeks after the initial immunizations were high for each group: DD(89.5 %),DS(63.2 %),SS(50 %) and II (44.7 %). These results indicated that the MCP DNA vaccine is the most suitable and promising vaccine candidate for the effective control of LMBV disease.

Computational Analysis of a Marine-Derived Drug From Rhizophora mucronata Against the Capsid Protein of Rubella Virus.

Background Rubella, commonly known as German measles, is caused by a single-stranded RNA genome. Vaccination is currently the most effective method for preventing rubella and its complications. Molecular docking, a computer-based technique used in drug discovery and development, is used to investigate the interactions between potential drug candidates and their target proteins. It predicts the binding interactions between small molecules (ligands) and the target protein. In this study, we examined a marine-derived drug from Rhizophora mucronata for its potential antiviral properties against the rubella capsid virus. Our objective was to identify the active inhibitory sites of the capsid virus. Materials and methods Protein and ligand molecules were retrieved from Protein Data Bank(PDB) and PubChem databases. The Lamarckian genetic algorithm was used to calculate molecular docking using Autodock Tools 1.5.7. The docking parameters used for each docked molecule were determined from 100 separate docking experiments with a maximum of 2.5×10-6 energy and a mutation rate of 2.0 and mass over ratio of 0.8. The results were recorded as docking parameter files (DPF). PyMOL was used to view and investigate the interactions between ligand fragments and rubella capsid protein. Results This approach plays a crucial role in the development of structure-based drugs. The results of the molecular docking suggest that Rhizophorin has the potential to bind with the rubella capsid protein. The strong binding affinity of -6.05 kcal/mol between the ligand and the protein further supports the potential of Rhizophorin as a therapeutic agent. The formation of hydrogen bonds between the ligand and amino acid residues Glu79, Arg82, and Thr118 indicates the significance of electrostatic interactions in the binding process. Furthermore, the hydrophobic interactions between the ligand and residues Ala81, Val84, Leu87, and Ile119 suggest the role of non-polar interactions in stabilizing the complex. The identified amino acid residues involved in these binding interactions could serve as potential targets for drug development. In future studies, experimental validation of the predicted interactions could provide further insights into the potential of Rhizophorin as an antiviral agent. Conclusion According to the findings of this study, the in silico investigation successfully identified a target for inhibiting the rubella virus (RuV) capsid receptor molecule. Future investigations on these compounds will require in vitro and in vivo studies using models that are more relevant to the medicinal potential of the capsid protein molecule.

The effect of pH on the structure of Bluetongue virus VP5.

The unenveloped Bluetongue virus capsid comprises several structural layers, the inner two comprising a core, which assembles before addition of the outer proteins, VP2 and VP5. Two symmetric trimers of VP5 fit like pegs into two distinct pits on the core and undergo pH conformational changes in the context of the virus, associated with cell entry. Here we show that in isolation VP5 alone undergoes essentially the same changes with pH and confirm a helical transition, indicating that VP5 is a motor during cell entry. In the absence of VP5 the two pits on the core differ from each other, presumably due to the asymmetric underlying structure of VP3, the innermost capsid protein. On insertion of VP5 these pits become closely similar and remain similar at low pH whilst VP5 is present. This natural asymmetry presumably destabilises the attachment of VP5, facilitating ejection upon low pH, membrane penetration and cell entry.

Realization of Higher Resolution Charge Detection Mass Spectrometry.

Charge detection mass spectrometry (CD-MS) allows mass distributions to be measured for heterogeneous samples that cannot be analyzed by conventional MS. With CD-MS, the m/z and charge are measured for individual ions using a detection cylinder embedded in an electrostatic linear ion trap (ELIT). Imprecision in both the m/z and charge measurements contribute to the mass resolution. However, if the charge can be measured with a precision of <0.2 e the charge state can be assigned with a low error rate and the mass resolving power only depends on the m/z resolution. Prior to this work, the best resolving power demonstrated experimentally for CD-MS was 700. Here we demonstrate a resolving power of >14,600, 20-times higher than the previous best. Trajectory simulations were used to optimize the geometry and electrostatic potentials of the ELIT. We found conditions where the energy dependence of the oscillation frequency becomes parabolic, and then operated with a nominal ion energy at the minimum of the parabola. The 14,600 resolving power was obtained with a beam collimator before the ELIT. With the collimator removed, the resolving power of the optimized ELIT is 7300, which is still an order of magnitude higher than the previous best. The resolving power was demonstrated by resolving the isotope distributions for peptides and proteins. High resolution CD-MS measurements were then used to resolve the glycans on a monoclonal antibody and applied to the analysis of hepatitis B virus capsids. The results indicate that procedures for adduct removal need to be improved for the full benefit of the higher resolving power to be realized for higher mass species. However, these results represent a key step toward using CD-MS to analyze very complex protein mixtures where charge states are not well resolved in the m/z spectrum because of congestion from numerous overlapping peaks.

Retraction for Shepardson et al., "Induction of Antiviral Immune Response through Recognition of the Repeating Subunit Pattern of Viral Capsids Is Toll-Like Receptor 2 Dependent".

Retraction for Shepardson et al., "Induction of Antiviral Immune Response through Recognition of the Repeating Subunit Pattern of Viral Capsids Is Toll-Like Receptor 2 Dependent".

Chemically Tagging Cargo for Specific Packaging inside and on the Surface of Virus-like Particles.

Virus-like particles (VLPs) have untapped potential for packaging and delivery of macromolecular cargo. To be a broadly useful platform, there needs to be a strategy for attaching macromolecules to the inside or the outside of the VLP with minimal modification of the platform or cargo. Here, we repurpose antiviral compounds that bind to hepatitis B virus (HBV) capsids to create a chemical tag to noncovalently attach cargo to the VLP. Our tag consists of a capsid assembly modulator, HAP13, connected to a linker terminating in maleimide. Our cargo is a green fluorescent protein (GFP) with a single addressable cysteine, a feature that can be engineered in many proteins. The HAP-GFP construct maintained HAP's intrinsic ability to bind HBV capsids and accelerate assembly. We investigated the capacity of HAP-GFP to coassemble with HBV capsid protein and bind to preassembled capsids. HAP-GFP binding was concentration-dependent, sensitive to capsid stability, and dependent on linker length. Long linkers had the greatest activity to bind capsids, while short linkers impeded assembly and damaged intact capsids. In coassembly reactions, >20 HAP-GFP molecules were presented on the outside and inside of the capsid, concentrating the cargo by more than 100-fold compared to bulk solution. We also tested an HAP-GFP with a cleavable linker so that external GFP molecules could be removed, resulting in exclusive internal packaging. These results demonstrate a generalizable strategy for attaching cargo to a VLP, supporting development of HBV as a modular VLP platform.

Evidence of aberrant anti-epstein-barr virus antibody response, though no viral reactivation, in people with post-stroke fatigue

BackgroundFatigue is a common complication of stroke that has a significant impact on quality of life. The biological mechanisms that underly post-stroke fatigue are currently unclear, however, reactivation of latent viruses and their impact on systemic immune function have been increasingly reported in other conditions where fatigue is a predominant symptom. Epstein-Barr virus (EBV) in particular has been associated with fatigue, including in long-COVID and myalgic encephalomyelitis/chronic fatigue syndrome, but has not yet been explored within the context of stroke.AimsWe performed an exploratory analysis to determine if there is evidence of a relationship between EBV reactivation and post-stroke fatigue.MethodsIn a chronic ischemic stroke cohort (> 5 months post-stroke), we assayed circulating EBV by qPCR and measured the titres of anti-EBV antibodies by ELISA in patients with high fatigue (FACIT-F < 40) and low fatigue (FACIT-F > 41). Statistical analysis between two-groups were performed by t-test when normally distributed according to the Shapiro-Wilk test, by Mann-Whitney test when the data was not normally distributed, and by Fisher’s exact test for categorical data.ResultsWe observed a similar incidence of viral reactivation between people with low versus high levels of post-stroke fatigue (5 of 22 participants (24%) versus 6 of 22 participants (27%)). Although the amount of circulating EBV was similar, we observed an altered circulating anti-EBV antibody profile in participants with high fatigue, with reduced IgM against the Viral Capsid Antigen (2.244 ± 0.926 vs. 3.334 ± 2.68; P = 0.031). Total IgM levels were not different between groups indicating this effect was specific to anti-EBV antibodies (3.23 × 105 ± 4.44 × 104 high fatigue versus 4.60 × 105 ± 9.28 × 104 low fatigue; P = 0.288).ConclusionsThese data indicate that EBV is not more prone to reactivation during chronic stroke recovery in those with post-stroke fatigue. However, the dysregulated antibody response to EBV may be suggestive of viral reactivation at an earlier stage after stroke.

Association between Epstein-Barr virus reactivation and severe malaria in pregnant women living in a malaria-endemic region of Cameroon.

Malaria kills nearly 619,000 people each year. Despite the natural immunity acquired to malaria, pregnant women and children under five die from severe forms of the disease in sub-Saharan Africa. Co-infection with acute Epstein-Barr Virus (EBV) infection has been shown to suppress the anti-malarial humoral responses, but little is known about the impact of EBV reactivation on malaria-associated morbidity. This study investigated the association between EBV reactivation and malaria severity in pregnant women living in a malaria-endemic region in Cameroon. A cross-sectional study was conducted on 220 pregnant women attending antenatal consultations in three health facilities in the West region of Cameroon. Malaria was diagnosed by microscopy, and Plasmodium species were identified by Nested PCR. Plasma samples were analyzed by ELISA for the presence of EBV nuclear antigen, EBV viral capsid antigen, and EBV early antigen to determine EBV reactivation. All statistics were performed using GraphPad Prism and SPSS software. The prevalence of malaria among pregnant women was 23.2%, of which 18.6% were P. falciparum mono-infections and 4.5% mixed infections (3.6% P. falciparum and P. malariae; 0.9% P. falciparum and P. ovale). 99.5% of the women were EBV seropositive, and 13.2% had EBV reactivation. Pregnant women with reactivated EBV were more likely to develop severe malaria than pregnant women with latent EBV (OR 4.33, 95% CI 1.08-17.25, p = 0.03). The median parasitemia in pregnant women with latent EBV was lower than in those with EBV reactivation (2816 vs. 19002 parasites/μL, p = 0.02). Our study revealed that lytic reactivation of EBV may be associated with the severity of malaria in pregnant women. Suggesting that, like acute infection, EBV reactivation should be considered a risk factor for severe malaria in pregnant women in malaria-endemic regions or could serve as a hallmark of malaria severity during pregnancy. Further detailed studies are needed.

Cholesterol-Dependent Membrane Deformation by Metastable Viral Capsids Facilitates Entry.

Nonenveloped viruses employ unique entry mechanisms to breach and infect host cells. Understanding these mechanisms is crucial for developing antiviral strategies. Prevailing perspective suggests that nonenveloped viruses release membrane pore-forming peptides to breach host membranes. However, the precise involvement of the viral capsid in this entry remains elusive. Our study presents direct observations elucidating the dynamically distinctive steps through which metastable reovirus capsids disrupt host lipid membranes as they uncoat into partially hydrophobic intermediate particles. Using both live cells and model membrane systems, our key finding is that reovirus capsids actively deform and permeabilize lipid membranes in a cholesterol-dependent process. Unlike membrane pore-forming peptides, these metastable viral capsids induce more extensive membrane perturbations, including budding, bridging between adjacent membranes, and complete rupture. Notably, cholesterol enhances subviral particle adsorption, resulting in the formation of pores equivalent to the capsid size. This cholesterol dependence is attributed to the lipid condensing effect, particularly prominent at an intermediate cholesterol level. Furthermore, our results reveal a positive correlation between membrane disruption extent and efficiency of viral variants in establishing infection. This study unveils the crucial role of capsid-lipid interaction in nonenveloped virus entry, providing new insights into how cholesterol homeostasis influences virus infection dynamics.