Virus Attachment Research Articles

Production of recombinant lumpy skin disease virus A27L and L1R proteins for application in diagnostics and vaccine development

Vaccination using live attenuated vaccines (LAVs) is considered the most effective method for control of lumpy skin disease (LSD). However, this method is limited by safety concerns, with reports of adverse reactions following vaccination. This study evaluates A27L and L1R which are essential proteins for virus attachment and membrane fusion as recombinant sub-unit vaccines against LSD. These proteins were recombinantly expressed in Escherichia coli and purified using affinity chromatography. Purified proteins were formulated individually (A27L or L1R) and in combination (A27L and L1R) with 10% (w/w) Montanide™ Gel 01 PR adjuvant at a final antigen dose of 20 µg per protein. The safety and immunogenicity of these formulations were evaluated in rabbits in a 42-day clinical trial. Animals were vaccinated on day 0 and boost injection administered 21 days later. No reduced morbidity, increased temperature and any other clinical signs were recorded in vaccinated animals for all three vaccine formulations. The highest neutralizing antibody response was detected on day 42 post-primary vaccination for all formulations when using serum neutralising assay. The neutralisation data correlates with antibody titres quantified using a whole cell ELISA. Evaluating the combination of A27L and L1R as potential diagnostic reagents showed highest sensitivity for detection of antibodies against LSD when compared to individual proteins. This study reports the immunogenicity of recombinant A27L and L1R combination for successful application in LSD vaccine development. Furthermore, these proteins demonstrated the potential use in LSD diagnostics.

Chronic encephalomyelitis virus exhibits cellular tropism and evades pDCs by binding to sialylated integrins as the cell surface receptors.

Theiler's murine encephalomyelitis virus (TMEV) causes a chronic demyelinating disease similar to multiple sclerosis in mice. Although sialic acids have been shown to be essential for TMEV attachment to the host, the surface receptor has not been identified. While type I interferons play a pivotal role in the elimination of the chronic infectious Daniel (DA) strain, the role of plasmacytoid dendritic cells (pDCs) is controversial. We herein found that TMEV binds to conventional DCs but not to pDCs. A glycomics analysis showed that the sialylated N-glycan fractions were lower in pDCs than in conventional DCs, indicating that pDCs are not susceptible to TMEV infection due to the low levels of sialic acid. TMEV capsid proteins contain an integrin recognition motif, and dot blot assays showed that the integrin proteins bind to TMEV and that the viral binding was reduced in the desialylated αX β2 . αX β2 protein suppressed TMEV replication in vivo, and TMEV co-localized with integrin αM at the cell membrane and TLR 3 in the cytoplasm, suggesting that αM serves as the viral attachment and entry. These results show that the chronic encephalomyelitis virus utilizes sialylated integrins as cell surface receptors, leading to cellular tropism to evade pDC activation.

The CD46 ectodomain participates in human cytomegalovirus infection of epithelial cells.

Human cytomegalovirus (HCMV) primary infections are typically asymptomatic in healthy individuals yet can cause increased morbidity and mortality in organ transplant recipients, AIDS patients, neonates, and the elderly. The successful, widespread dissemination of this virus among the population can be attributed in part to its wide cellular tropism and ability to establish life-long latency. HCMV infection is a multi-step process that requires numerous cellular and viral factors. The viral envelope consists of envelope protein complexes that interact with cellular factors; such interactions dictate virus recognition and attachment to different cell types, followed by fusion either at the cell membrane or within an endocytic vesicle. Several HCMV entry factors, including neuropilin-2 (Nrp2), THBD, CD147, OR14I1, and CD46, are characterized as participating in HCMV pentamer-specific entry of non-fibroblast cells such as epithelial, trophoblast, and endothelial cells, respectively. This study focuses on characterizing the structural elements of CD46 that impact HCMV infection. Infectivity studies of wild-type and CD46 knockout epithelial cells demonstrated that levels of CD46 expressed on the cell surface were directly related to HCMV infectivity. Overexpression of CD46 isomers BC1, BC2, and C2 enhanced infection. Further, CD46 knockout epithelial cells expressing CD46 deletion and chimeric molecules identified that the intact ectodomain was critical for rescue of HCMV infection in CD46 knockout cells. Collectively, these data support a model that the extracellular domain of CD46 participates in HCMV infection due to its surface expression.

Attachment, Entry, and Intracellular Trafficking of Classical Swine Fever Virus.

Classical swine fever virus (CSFV), which is a positive-sense, single-stranded RNA virus with an envelope, is a member of the Pestivirus genus in the Flaviviridae family. CSFV causes a severe and highly contagious disease in pigs and is prevalent worldwide, threatening the pig farming industry. The detailed mechanisms of the CSFV life cycle have been reported, but are still limited. Some receptors and attachment factors of CSFV, including heparan sulfate (HS), laminin receptor (LamR), complement regulatory protein (CD46), MER tyrosine kinase (MERTK), disintegrin, and metalloproteinase domain-containing protein 17 (ADAM17), were identified. After attachment, CSFV internalizes via clathrin-mediated endocytosis (CME) and/or caveolae/raft-dependent endocytosis (CavME). After internalization, CSFV moves to early and late endosomes before uncoating. During this period, intracellular trafficking of CSFV relies on components of the endosomal sorting complex required for transport (ESCRT) and Rab proteins in the endosome dynamics, with a dependence on the cytoskeleton network. This review summarizes the data on the mechanisms of CSFV attachment, internalization pathways, and intracellular trafficking, and provides a general view of the early events in the CSFV life cycle.

Tailoring multivalent nanomedicines for monkeypox

We have been through the largest monkeypox (Mpox) outbreak that has ever occurred globally. At present, the application of nanotechnology-based approaches to tackle Mpox has not been established. There are no US FDA-approved treatments for Mpox and it is plausible that, in forthcoming studies, researchers may investigate the use of multivalent nanomaterials to target the virus. In contrast to monovalent ligands, multi- and polyvalent ligands have strong affinity for the target molecules, thereby significantly facilitating the inhibition of viral attachment to host cells. Multivalent interactions are crucial in signal processing, adhesion, and recognition within biological systems. Based on the understanding of the development of multivalent nanomaterials (such as phage capsid nanoparticles, engineered bacteriophage T4 and self-assembled DNA nanobait) for SARS-CoV-2, influenza, and other viruses, this brief perspective gives insights into the development of next-generation multivalent nanomedicines targeting the entry-fusion complex of Mpox as a promising strategy for tackling emerging mutated strains.

Virulence and transmission characteristics of clade 2.3.4.4b H5N6 subtype avian influenza viruses possessing different internal gene constellations

ABSTRACT Clade 2.3.4.4 H5N6 avian influenza virus (AIV) has been predominant in poultry in China, and the circulating haemagglutinin (HA) gene has changed from clade 2.3.4.4h to clade 2.3.4.4b in recent years. In 2021, we isolated four H5N6 viruses from ducks during the routine surveillance of AIV in China. The whole-genome sequencing results demonstrated that the four isolates all belonged to the currently prevalent clade 2.3.4.4b but had different internal gene constellations, which could be divided into G1 and G2 genotypes. Specifically, G1 possessed H9-like PB2 and PB1 genes on the H5-like genetic backbone while G2 owned an H3-like PB1 gene and the H5-like remaining internal genes. By determining the characteristics of H5N6 viruses, including growth performance on different cells, plaque-formation ability, virus attachment ability, and pathogenicity and transmission in different animal models, we found that G1 strains were more conducive to replication in mammalian cells (MDCK and A549) and BALB/c mice than G2 strains. However, G2 strains were more advantageously replicated in avian cells (CEF and DF-1) and slightly more transmissible in waterfowls (mallards) than G1 strains. This study enriched the epidemiological data of H5 subtype AIV to further understand its dynamic evolution, and laid the foundation for further research on the mechanism of low pathogenic AIV internal genes in generating novel H5 subtype reassortants.

Novel CRISPR-Cas9 approach to combat with COVID-19

Background: The recent outbreak of Corona Virus has affected people all over the world so that WHO declared it a pandemic. This pandemic has become a major problem for people, health professionals, and research institutes that how to combat SARS-CoV-2. The objective of this review article is to provide a brief study that CRISPR/Cas9 can be used to combat SARS-CoV-2. Methods: The comparison of three genome editing techniques (ZNF, TALEN, and CRISPR/Cas9) is done. The mechanism of action of CRISPR/Cas9 is discussed. Results: The studies provided in this review article suggest that it is difficult to recognize this virus as they have their own metabolic machinery and they replicate their selves in the host cell and consume host cellular products to perform their own functions. The COVID-19 proteins may contain some specific areas that are suitable targets for therapy, such as tiny inhibitor molecules for viral polymerase, or impede the attachment of viruses to the receptor sites, for example, viral coat proteins can be used for vaccination purposes. Conclusion: CRISPR-Cas9 can be used to control the SARS-CoV-2 genome from replication and spread to other parts of the body as it can edit the genome quite efficiently. This proposed model will help in targeting the SARS-CoV-2 genome more precisely in the future.

Nano-Enabled Antivirals for Overcoming Antibody Escaped Mutations Based SARS-CoV-2 Waves.

This review discusses receptor-binding domain (RBD) mutations related to the emergence of various SARS-CoV-2 variants, which have been highlighted as a major cause of repetitive clinical waves of COVID-19. Our perusal of the literature reveals that most variants were able to escape neutralizing antibodies developed after immunization or natural exposure, pointing to the need for a sustainable technological solution to overcome this crisis. This review, therefore, focuses on nanotechnology and the development of antiviral nanomaterials with physical antagonistic features of viral replication checkpoints as such a solution. Our detailed discussion of SARS-CoV-2 replication and pathogenesis highlights four distinct checkpoints, the S protein (ACE2 receptor coupling), the RBD motif (ACE2 receptor coupling), ACE2 coupling, and the S protein cleavage site, as targets for the development of nano-enabled solutions that, for example, prevent viral attachment and fusion with the host cell by either blocking viral RBD/spike proteins or cellular ACE2 receptors. As proof of this concept, we highlight applications of several nanomaterials, such as metal and metal oxide nanoparticles, carbon-based nanoparticles, carbon nanotubes, fullerene, carbon dots, quantum dots, polymeric nanoparticles, lipid-based, polymer-based, lipid-polymer hybrid-based, surface-modified nanoparticles that have already been employed to control viral infections. These nanoparticles were developed to inhibit receptor-mediated host-virus attachments and cell fusion, the uncoating of the virus, viral gene expression, protein synthesis, the assembly of progeny viral particles, and the release of the virion. Moreover, nanomaterials have been used as antiviral drug carriers and vaccines, and nano-enabled sensors have already been shown to enable fast, sensitive, and label-free real-time diagnosis of viral infections. Nano-biosensors could, therefore, also be useful in the remote testing and tracking of patients, while nanocarriers probed with target tissue could facilitate the targeted delivery of antiviral drugs to infected cells, tissues, organs, or systems while avoiding unwanted exposure of non-target tissues. Antiviral nanoparticles can also be applied to sanitizers, clothing, facemasks, and other personal protective equipment to minimize horizontal spread. We believe that the nanotechnology-enabled solutions described in this review will enable us to control repeated SAR-CoV-2 waves caused by antibody escape mutations.

The antiviral activity of Thuja orientalis folium against Influenza A virus

Thuja orientalis Folium (TOF) has been prescribed traditionally as an expectorant for inflammatory airway disease. In this study, we evaluated the anti-influenza A virus (IAV) activity of TOF by detecting GFP expressed by influenza A virus (A/PR/8/34-GFP) infection. The fluorescence microscopy and fluorescence-activated cell sorting analysis showed that TOF potently inhibited IAV infection, dose-dependently. Consistently, immunofluorescence and Q-PCR analysis results confirmed TOF significantly represses IAV protein and RNA expression. TOF inhibited IAV infection at the binding and entry step upon viral infection and interferes with HA protein. Further, TOF exhibited a virucidal effect and inhibited the neuraminidase activity of IAV. Additionally, TOF prevented the cytopathic effect caused by H1N1 and H3N2 IAV infection. Amentoflavone among the constituents in TOF exerted the strongest anti-IAV effect. Myricetin, quercetin, and quercitrin also inhibited IAV infection. However, the potent anti-IAV effect of TOF may be related to the synergistic effect of constituents, not by a single specific compound. Our results suggest TOF exhibits a significant inhibitory effect against IAV infection at multi-stages via the blockage of viral attachment and entry, inhibition of neuraminidase, and induction of virucidal effects.

Genome-wide study of globally distributed respiratory syncytial virus (RSV) strains implicates diversification utilizing phylodynamics and mutational analysis

Respiratory syncytial virus (RSV) is a common respiratory pathogen that causes mild cold-like symptoms and severe lower respiratory tract infections, causing hospitalizations in children, the elderly and immunocompromised individuals. Due to genetic variability, this virus causes life-threatening pneumonia and bronchiolitis in young infants. Thus, we examined 3600 whole genome sequences submitted to GISAID by 31 December 2022 to examine the genetic variability of RSV. While RSVA and RSVB coexist throughout RSV seasons, RSVA is more prevalent, fatal, and epidemic-prone in several countries, including the United States, the United Kingdom, Australia, and China. Additionally, the virus's attachment glycoprotein and fusion protein were highly mutated, with RSVA having higher Shannon entropy than RSVB. The genetic makeup of these viruses contributes significantly to their prevalence and epidemic potential. Several strain-specific SNPs co-occurred with specific haplotypes of RSVA and RSVB, followed by different haplotypes of the viruses. RSVA and RSVB have the highest linkage probability at loci T12844A/T3483C and G13959T/C2198T, respectively. The results indicate that specific haplotypes and SNPs may significantly affect their spread. Overall, this analysis presents a promising strategy for tracking the evolving epidemic situation and genetic variants of RSV, which could aid in developing effective control, prophylactic, and treatment strategies.

In silico prediction of siRNA to silence the SARS-CoV-2 omicron variant targeting BA.4, BA.5, BQ.1, BQ1.1. and XBB: an alternative to traditional therapeutics

BackgroundAfter the first infection in December 2019, the mutating strains of SARS-CoV2 have already affected a lot of healthy people around the world. But situations have not been as devastating as before the first pandemic of the omicron strains of SARS-CoV2. As of January 2023, five more Omicron offshoots, BA.4, BA.5, B.Q.1, B.Q.1.1 and XBB are now proliferating worldwide. Perhaps there are more variants already dormant that require only minor changes to resurrect. So, this study was conducted with a view to halting the infection afterwards. The spike protein found on the virus outer membrane is essential for viral attachment to host cells, thus making it an attractive target for vaccine, drug, or any other therapeutic development. Small interfering RNAs (siRNAs) are now being used as a potential treatment for various genetic conditions or as antiviral or antibacterial therapeutics. Thus, in this study, we looked at spike protein to see if any potential siRNAs could be discovered from it.ResultsIn this study, by approaching several computational assays (e.g., GC content, free energy of binding, free energy of folding, RNA–RNA binding, heat capacity, concentration plot, validation, and finally molecular docking analysis), we concluded that two siRNAs could be effective to silence the spike protein of the omicron variant. So, these siRNAs could be a potential target for therapeutic development against the SARS-CoV2 virus by silencing the spike protein of this virus.ConclusionWe believe our research lays the groundwork for the development of effective therapies at the genome level and might be used to develop chemically produced siRNA molecules as an antiviral drug against SARS-CoV2 virus infection.Graphical abstract

The Effects of Herpes Virus Glycoprotein Glycosylation On Viral Infection and Pathogenesis

Herpes virus is an enveloped virus with many glycoproteins essential for viral infection and immune evasion. Several glycosylation sites exist on the glycoproteins of herpes viruses, including N- and O-glycosylation sites. Glycosylation affects herpes virus infection and pathogenesis in different ways, including the attachment and entry of the herpes virus into host cells, virus replication and the host's immune function. This article summarized the current knowledge on the glycosylation of herpes virus envelope glycoproteins and its impact on viral infection and demonstrated several applications of glycosylation inhibitors.

Mechanistic Understanding of the Antiviral Properties of Pistachios and Zeaxanthin against HSV-1.

The search for alternative clinical treatments to fight resistance and find alternative antiviral treatments for the herpes simplex virus (HSV) is of great interest. Plants are rich sources of novel antiviral, pharmacologically active agents that provide several advantages, including reduced side effects, less resistance, low toxicity, and different mechanisms of action. In the present work, the antiviral activity of Californian natural raw (NRRE) and roasted unsalted (RURE) pistachio polyphenols-rich extracts was evaluated against HSV-1 using VERO cells. Two different extraction methods, with or without n-hexane, were used. Results showed that n-hexane-extracted NRRE and RURE exerted an antiviral effect against HSV-1, blocking virus binding on the cell surface, affecting viral DNA synthesis as well as accumulation of ICP0, UL42, and Us11 viral proteins. Additionally, the identification and quantification of phenolic compounds by RP-HPLC-DAD confirmed that extraction with n-hexane exclusively accumulated tocopherols, carotenoids, and xanthophylls. Amongst these, zeaxanthin exhibited strong antiviral activity against HSV-1 (CC50: 16.1 µM, EC50 4.08 µM, SI 3.96), affecting both the viral attachment and penetration and viral DNA synthesis. Zeaxanthin is a dietary carotenoid that accumulates in the retina as a macular pigment. The use of pistachio extracts and derivates should be encouraged for the topical treatment of ocular herpetic infections.

Comparison of Sequencing and Phylogenetic Analysis of SARS-CoV-2 Spike Proteins Extracted from Patients and Travelers in Duhok-Iraq

Background: SARS-CoV-2 is a single-stranded RNA virus and a member of a large family of Coronaviruses that are important human pathogens. This virus caused severe acute respiratory syndrome and was initially identified to be transmitted between humans on November 17, 2019. Objectives: To investigate the lineage, mutational patterns, variants, and serotypes of SARS-CoV-2 viruses circulating in the Duhok governorate population and to compare them with those identified in travelers crossing the border from Turkey in order to trace the epidemiological patterns. Methods: Nasopharyngeal swabs were collected from 700 individuals living in Duhok and 700 travelers crossing the border to Duhok-Iraq from Turkey. The subjects were recruited by random sampling and questioned about demographic features and symptoms of upper or lower respiratory tract infections. Exclusion criteria included vaccination with COVID-19 vaccines of any approved previous infection. Samples were subjected to RT-PCR, and 30 positive samples with the highest viral load (lowest Ct values) were chosen for sequencing of the complete S gene by next-generation sequencing (NGS). Three platforms of Nextstrain, GISAID, and PANGO were used to identify variants, clades, and lineages and analyze sequences. Results: Out of 1400 participants, 353 (25.21%) positive samples were identified by RT-PCR, of which 30 representative positive samples (15 from each group: Patients and travelers) were sent for complete sequencing of the S spike gene using NGS. Nineteen samples were successfully sequenced and retrieved, including nine samples from Duhok residents and ten samples from travelers. Nextclade results revealed that 12 samples belonged to the delta strain (Pango lineages: B1.617.2.78, B1.617.2, B1.617.126, and B.1.617.121) distributed among the two groups while 5 omicron (BA.1.1) and 2 alpha (B.1.1.7) strains were found among travelers. A total of 76 mutations, including 52 non-synonymous, 16 synonymous, and 8 deletions, were detected without identifying a unique mutation. Sequencing results were submitted to GISAID, and accession numbers were obtained. A phylogenetic tree was constructed using the sequences obtained from Iraqi and non-Iraqi variants from GISAID. Conclusions: The present research presents a description and observation of the genetic and epigenetic status of SARS-CoV-2 in Iraq based on sequencing results. The study revealed the impact of travels in introducing new variants to the country, including those with mutations in the S1 domain of the spike protein that can enhance viral attachment to receptors.

Nipah virus attachment glycoprotein ectodomain delivered by type 5 adenovirus vector elicits broad immune response against NiV and HeV.

Nipah virus (NiV) and Hendra virus (HeV) are newly emerging dangerous zoonotic pathogens of the Henipavirus genus of the Paramyxoviridae family. NiV and HeV (HNVs) which are transmitted by bats cause acute respiratory disease and fatal encephalitis in humans. To date, as there is a lack of antiviral drugs or effective antiviral therapies, the development of vaccines against those two viruses is of primary importance, and the immunogen design is crucial to the success of vaccines. In this study, the full-length protein (G), the ectodomain (Ge) and the head domain (Gs) of NiV attachment glycoprotein were delivered by the replication-defective type 5 adenovirus vector (Ad5) respectively, and the recombinant Ad5-NiV vaccine candidates (Ad5-NiVG, Ad5-NiVGe and Ad5-NiVGs) were constructed and their immunogenicity were evaluated in mice. The results showed that all the vaccine candidates stimulated specific humoral and cellular immune responses efficiently and rapidly against both NiV and HeV, and the Ad5-NiVGe elicited the strongest immune responses after a single-dose immunization. Furthermore, the potent conserved T-cell epitope DTLYFPAVGFL shared by NiV and HeV was identified in the study, which may provide valid information on the mechanism of HNVs-specific cellular immunity. In summary, this study demonstrates that the Ad5-NiVGe could be a potent vaccine candidate against HNVs by inducing robust humoral and cellular immune responses.

Computational peptide engineering approach for selection of the new C05 antibody-driven peptide with potency to blocking influenza a virus attachment; from in silico to in vivo

Antiviral drugs are currently used to prevent or treat viral infections like influenza A Virus (IAV). Nonetheless, annual genetic mutations of influenza viruses make them resistant to efficient treatment by current medications. Antiviral peptides have recently attracted researchers’ attention and can potentially supplant the current medications. This study aimed to design peptides against IAV propagation. For this purpose, P2 and P3 peptides were computationally designed based on the HCDR3 region of the C05 antibody (a monoclonal antibody that neutralizes influenza HA protein and inhibits the virus attachment). The synthesized peptides were tested against the influenza A virus (A/Puerto Rico/8/34 (H1N1)) in vitro, and the most efficient peptide was selected for in vivo experiments. It was shown that the designed peptide shows much more prophylactic and therapeutic effects against the virus. These findings demonstrated that the designed peptide can control the virus infection without any cytotoxicity effect. Antiviral peptide design is acknowledged as a critical tactic to manage viral infections by preventing viral binding to the host cells. Communicated by Ramaswamy H. Sarma

Identifying and profiling structural similarities between Spike of SARS-CoV-2 and other viral or host proteins with Machaon

Using protein structure to predict function, interactions, and evolutionary history is still an open challenge, with existing approaches relying extensively on protein homology and families. Here, we present Machaon, a data-driven method combining orientation invariant metrics on phi-psi angles, inter-residue contacts and surface complexity. It can be readily applied on whole structures or segments—such as domains and binding sites. Machaon was applied on SARS-CoV-2 Spike monomers of native, Delta and Omicron variants and identified correlations with a wide range of viral proteins from close to distant taxonomy ranks, as well as host proteins, such as ACE2 receptor. Machaon’s meta-analysis of the results highlights structural, chemical and transcriptional similarities between the Spike monomer and human proteins, indicating a multi-level viral mimicry. This extended analysis also revealed relationships of the Spike protein with biological processes such as ubiquitination and angiogenesis and highlighted different patterns in virus attachment among the studied variants. Available at: https://machaonweb.com.

Antiviral Lectins of the Plant Family Amaryllidaceae

AbstractPlants have long served as a first line of defence against viral-borne diseases. Their chemical constituents have also afforded a sound basis for antiviral drug discovery. The plant family Amaryllidaceae is distinguished for its isoquinoline alkaloids, some of which have proved to be interesting antiviral drug leads. Its lectin (or agglutinin) principles have likewise attracted considerable attention as potential antiviral drugs. This review focuses on the antiviral activities that have been described for the lectins of the Amaryllidaceae. Of the thirty lectins known in the family, fourteen have been screened against nearly seventy pathogens belonging to thirteen viral families. Whilst good activities were reported in most cases, the lectins from Galanthus nivalis, Narcissus pseudonarcissus and Hippeastrum hybrid were identified with the best overall activities. They displayed potent inhibitory effects against the human immunodeficiency virus HIV-1(IIIB) proliferation in CEM lymphoblastic cells (EC50s 0.005, 0.009 and 0.004 μM, respectively). Although significant effort was dedicated to the Retroviridae, noteworthy effects were also observed against members of other viral families (such as hepatitis C virus of the Flaviviridae). Furthermore, the lectins were shown to be highly selective antiviral agents, devoid of significant toxicities towards the nearly forty cells employed as hosts. Almost all of the details of their modes of operation have emerged from studies carried out on HIV. They were shown to inhibit viral attachment, fusion and adsorption to a variety of host cells. Modulation of viral entry was shown to occur via interference with the virus envelope glycoprotein. These observations fit into the key biological characteristic of lectins, that of sugar-binding proteins. Graphical Abstract

Selective inhibition of hepatitis B virus internalization by oxysterol derivatives

Given that the current approved anti-hepatitis B virus (HBV) drugs suppress virus replication and improve hepatitis but cannot eliminate HBV from infected patients, new anti-HBV agents with different mode of action are urgently needed. In this study, we identified a semi-synthetic oxysterol, Oxy185, that can prevent HBV infection in a HepG2-based cell line and primary human hepatocytes. Mechanistically, Oxy185 inhibited the internalization of HBV into cells without affecting virus attachment or replication. We also found that Oxy185 interacted with an HBV entry receptor, sodium taurocholate cotransporting polypeptide (NTCP), and inhibited the oligomerization of NTCP to reduce the efficiency of HBV internalization. Consistent with this mechanism, Oxy185 also inhibited the hepatitis D virus infection, which relies on NTCP-dependent internalization, but not hepatitis A virus infection, and displayed pan-genotypic anti-HBV activity. Following oral administration in mice, Oxy185 showed sustained accumulation in the livers of the mice, along with a favorable liver-to-plasma ratio. Thus, Oxy185 is expected to serve as a useful tool compound in proof-of-principle studies for HBV entry inhibitors with this novel mode of action.

Mpox virus mRNA-lipid nanoparticle vaccine candidates evoke antibody responses and drive protection against the Vaccinia virus challenge in mice

In response to the human Mpox (hMPX) epidemic that began in 2022, there is an urgent need for a monkeypox vaccine. Here, we have developed a series of mRNA-lipid nanoparticle (mRNA-LNP)-based vaccine candidates that encode a collection of four highly conserved Mpox virus (MPXV) surface proteins involved in virus attachment, entry, and transmission, namely A29L, A35R, B6R, and M1R, which are homologs to Vaccinia virus (VACV) A27, A33, B5, and L1, respectively. Despite possible differences in immunogenicity among the four antigenic mRNA-LNPs, administering these antigenic mRNA-LNPs individually (5 μg each) or an average mixture of these mRNA-LNPs at a low dose (0.5 μg each) twice elicited MPXV-specific IgG antibodies and potent VACV-specific neutralizing antibodies. Furthermore, two doses of 5 μg of A27, B5, and L1 mRNA-LNPs or a 2 μg average mixture of the four antigenic mRNA-LNPs protected mice against weight loss and death after the VACV challenge. Overall, our data suggest that these antigenic mRNA-LNP vaccine candidates are both safe and efficacious against MPXV, as well as diseases caused by other orthopoxviruses.