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Scavenger receptor class F member 2 is an intracellular receptor for hepatitis B virus.

Hepatitis B virus (HBV) infects hepatocytes by specific binding to the cell-surface receptor-sodium taurocholate cotransporting polypeptide … orted to the cytoplasmic side of nuclear pore complexes within the SCARF2-containing endosomes. HBV nucleocapsid release from the endosomal vesicles is impaired by knockdown of SCARF2. These results suggest a model in which SCARF2 conveys HBV to the periphery of nuclear pore complexes (NPCs) and ultimately leads to viral nucleocapsid release for nuclear entry.

SARS-CoV-2 Spike Protein Binding of Glycated Serum Albumin-Its Potential Role in the Pathogenesis of the COVID-19 Clinical Syndromes and Bias towards Individuals with Pre-Diabetes/Type 2 Diabetes and Metabolic Diseases.

The immune response to SARS-CoV-2 infection requires antibody recognition of the spike protein. In a study designed to examine the molecular features of anti-spike and anti-nucleocapsid antibodies, patient plasma proteins binding to pre-fusion stabilised complete spike and nucleocapsid proteins were isolated and analysed by matrix-assisted laser desorption ionisation-time of flight (MALDI-ToF) mass spectrometry. Amongst the immunoglobulins, a high affinity for human serum albumin was evident in the anti-spike preparations. Careful mass comparison revealed the preferential capture of advanced g…

Circulating CD4 T Cells Elicited by Endemic Coronaviruses Display Vast Disparities in Abundance and Functional Potential Linked to Antigen Specificity and Age.

Repeated infections with endemic human coronaviruses (hCoV) are thought to reflect lack of long-lasting protective immunity. We evaluated ci … V-2) infection, we examined the subjects for cross-reactive recognition of epitopes from SARS-CoV-2 nucleocapsid, membrane/envelope, and spike. Functional potential of these cross-reactive CD4 T cells was highly variable; nucleocapsid-specific CD4 T cells but not spike-reactive cells showed exceptionally high levels of granzyme production upon stimulation. The …

Experimental subacute sclerosing panencephalitis: selective disappearance of measles virus matrix protein from the Central nervous system.

Subacute sclerosing panencephalitis (SSPE) is caused by a cell-associated or defective form of measles virus. The matrix protein of measles virus may be absent in patients with SSPE which could explain the defective nature of the virus in these patients. In an experimental model of SSPE in hamsters, measles virus in brain tissue is known to convert from a complete infectious form to a cell-associated or defective form eight to 12 days after intracerebral inoculation. Rabbit sera containing antibodies to two individual measles virus polypeptides, the nucleocapsid protein and matrix protein, wer…

Analyses of phosphorylation events in the rubella virus capsid protein: role in early replication events.

The Rubella virus capsid protein is phosphorylated prior to virus assembly. Our previous data are consistent with a model in which dynamic phosphorylation of the capsid regulates its RNA binding activity and, in turn, nucleocapsid assembly. In the present study, the process of capsid phosphorylation was examined in further detail. We show that phosphorylation of serine 46 in the RNA binding region of the capsid is required to trigger phosphorylation of additional amino acid residues that include threonine 47. This residue likely plays a direct role in regulating the binding of genomic RNA to t…

Measles virus panniculitis subsequent to vaccine administration.

A severe illness developed gradually in a healthy boy following administration of live measles vaccine at age 14 years. Killed measles vaccine had been given at age 2. Panniculitis began near the site of live vaccine injection, extended contiguously to involve the entire upper arm, and then began to appear in distant subcutaneous sites. He was febrile, leukopenic, anemic, and lost weight rapidly. Evidence of a cause-and-effect relationship between the lesions and the measles vaccine included biopsy findings of particles closely resembling measles nucleocapsids and complete virions by electron …

SARS-CoV-2 seeds IAPP aggregation and β-cell failure.

The global diabetes incidence has surged post-COVID-19, yet how SARS-CoV-2 drives long-term beta cell (β-cell) failure remains incompletely … ion, proximity ligation assays, and surface plasmon resonance experimentally confirmed direct spike/nucleocapsid-IAPP binding; interface-guided peptide mutagenesis further showed that five predicted IAPP contact residues are required for binding. Thioflavin-T kinetics and electron microscopy demonstrated that the spike/nucleocapsid markedly accelerated IAPP mo …

Expanding SARS-CoV-2 antigen targets beyond spike using a baculovirus expression system.

The ongoing antigenic evolution of SARS-CoV-2, particularly within the spike glycoprotein, threatens the long-term efficacy of spike-focused vaccines and serodiagnostics. While most authorized COVID-19 vaccines exclusively target the spike protein, growing evidence underscores multivalent strategies incorporating conserved viral antigens. Here, we employed a baculovirus expression vector system (BEVS) to co-express all four structural proteins, including spike, nucleocapsid, membrane, and envelope, in Sf9 insect cells. Surface-displayed antigens were used in a cell-based ELISA to profile IgG r…

Anti-SARS-CoV-2 antibodies from severe COVID-19 individuals or S2 immunizations do not worsen disease in hamsters.

Severe COVID-19 associates with humoral immune response dysregulation. While antibodies confer protection against SARS-CoV-2, evidence also support their putative contribution to disease severity. Our study demonstrates that higher levels of S2-IgG, and S2-, RBD-, and Nucleocapsid-IgA differentiate severe and non-severe cases. However, no major antibody functional differences are found between both COVID-19 manifestations. Enhanced Fc-dependent functions in severe cases are primarily driven by increased antibody titers. No differences in antibody avidity are found between severe and non-severe…

Capsid Assembly Modulators as Antiviral Agents against HBV: Molecular Mechanisms and Clinical Perspectives.

Despite a preventive vaccine being available, more than 250 million people suffer from chronic hepatitis B virus (HBV) infection, a major cause of liver disease and HCC. HBV infects human hepatocytes where it establishes its genome, the cccDNA with chromosomal features. Therapies controlling HBV replication exist; however, they are not sufficient to eradicate HBV cccDNA, the main cause for HBV persistence in patients. Core protein is the building block of HBV nucleocapsid. This viral protein modulates almost every step of the HBV life cycle; hence, it represents an attractive target for the de…

The Ebola Virus Interferon Antagonist VP24 Undergoes Active Nucleocytoplasmic Trafficking.

Viral interferon (IFN) antagonist proteins mediate evasion of IFN-mediated innate immunity and are often multifunctional, with distinct roles in viral replication. The Ebola virus IFN antagonist VP24 mediates nucleocapsid assembly, and inhibits IFN-activated signaling by preventing nuclear import of STAT1 via competitive binding to nuclear import receptors (karyopherins). Proteins of many viruses, including viruses with cytoplasmic replication cycles, interact with nuclear trafficking machinery to undergo nucleocytoplasmic transport, with key roles in pathogenesis; however, despite established…

Cryo EM structure of the rabies virus ribonucleoprotein complex.

Rabies virus is an important zoonotic pathogen. Its bullet shaped particle contains a helical nucleocapsid. We used cryo-electron tomography and subsequent subtomogram averaging to determine the structure of its ribonucleoprotein. The resulting electron density map allowed for confident fitting of the N-protein crystal structure, indicating that interactions between neighbouring N-proteins are only mediated by N- and C-terminal protruding subdomains (aa 1-27 and aa 355-372). Additional connecting densities, likely stabilizing the ribonucleoprotein complex, are present between neighbouring M-pr…

Ebola Virus Uses Tunneling Nanotubes as an Alternate Route of Dissemination.

Ebola virus (EBOV) disease is marked by rapid virus replication and spread. EBOV enters the cell by macropinocytosis and replicates in the c … at EBOV infection of primary human cells results in the enhanced formation of TNTs containing viral nucleocapsids. TNTs promote the intercellular transfer of nucleocapsids in the absence of live virus, and virus could replicate in cells devoid of entry factors after initial stall. Our studies suggest an alternate model of EBOV dissemination within the host, la …

Reflections on COVID-19: A Literature Review of SARS-CoV-2 Testing.

Although the Coronavirus disease 2019 (COVID-19) pandemic has ended, there are still many important lessons we can learn, as the pandemic pr … valuations were performed both in the earlier and later periods of the pandemic. They included both nucleocapsid/spike antibodies and automated antigen assays. Early in the pandemic, it was generally agreed that the initial nucleocapsid antibody assays had poor sensitivity when used before 14 days of disease onset, with total or IgG antibodies being preferred …

Evaluation of response to different COVID-19 vaccines in vaccinated healthcare workers in a single center in Iran.

Due to the recent coronavirus disease 2019 (COVID-19) pandemic and emergent administration of various vaccines worldwide, comprehensive stud … ds, including anti-SARS-CoV-2 neutralizing antibody by DiaZist and Pishtazteb kits, anti-SARS-CoV-2-nucleocapsid by Pishtazteb kit, and anti-SARS-CoV-2-Spike by Razi kit. The cutoff for the tests' results was calculated according to the instructions of each kit. Totally, 174 individuals with an average age of 40 ± 9 years participated in this study, the propor …

Evolution of a fuzzy ribonucleoprotein complex in viral assembly.

Previously, we showed that the genetic diversity of SARS-CoV-2 nucleocapsid (N) protein explores a wide range of biophysical properties facilitated by non-local impact of point mutations to its intrinsically disordered regions (Nguyen et al., 2024). This includes modulation of self-association, such as the creation of a de novo binding interface through the P13L mutation characteristic of Omicron variants. In the present work, we focus on the key function of N condensing viral RNA into ribonucleoprotein particles (RNPs) for viral assembly. Lacking high-resolution structural information, bioche…

Targeting the multifunctional HBV core protein as a potential cure for chronic hepatitis B.

The core (capsid) protein of hepatitis B virus (HBV) is the building block of nucleocapsids where viral DNA reverse transcriptional replication takes place and mediates virus-host cell interaction important for the persistence of HBV infection. The pleiotropic role of core protein (Cp) in HBV replication makes it an attractive target for antiviral therapies of chronic hepatitis B, a disease that affects more than 257 million people worldwide without a cure. Recent clinical studies indicate that core protein allosteric modulators (CpAMs) have a great promise as a key component of hepatitis B cu…

Multiple capsid protein binding sites mediate selective packaging of the alphavirus genomic RNA.

The alphavirus capsid protein (Cp) selectively packages genomic RNA (gRNA) into the viral nucleocapsid to produce infectious virus. Using photoactivatable ribonucleoside crosslinking and an innovative biotinylated Cp retrieval method, here we comprehensively define binding sites for Semliki Forest virus (SFV) Cp on the gRNA. While data in infected cells demonstrate Cp binding to the proposed genome packaging signal (PS), mutagenesis experiments show that PS is not required for production of infectious SFV or Chikungunya virus. Instead, we identify multiple Cp binding sites that are enriched on…

Maturation defect of a temperature-sensitive mutant of western equine encephalitis virus.

The defective step of a temperature-sensitive mutant of western equine encephalitis virus, which synthesize viral RNA but not mature virus at the restrictive temperature, was studied. Cells infected with the mutant virus at the restrictive temperature synthesized the same intracellular viral RNA as that in wild type infection. Cells infected with the mutant at the restrictive temperature formed three proteins (E1, E2 and C) which migrated to positions identical with those of purified virions and a precursor protein of E2 (PE2). The mutant virus was also able to form cytoplasmic nucleocapsids s…

Взаимосвязь между деятельностью по борьбе с вирусом кори и олигоклональным игГ в центральной нервной системе пациентов с субактным склерозом панэнцефалита и множественным склерозом.

После отделения электрофоретики была изучена связь между олигокланом и антителами вируса кори, присутствующими в образцах цереброспинной жидкости, или выдержками из материалов головного мозга у 9 пациентов с подводным склерозом панэнцефалита. Во всех образцах существует хорошая корреляция между присутствием групп ИГГ и конкретными видами антителной деятельности. Доминирующая группа олигоклана во всех случаях представляла антитела против антигена нуклеокапсида. Банды олигоклона с определенной антителной активностью продемонстрировали склонность занимать преференциальное положение в электроферог

Совпадение в аннотации оригинала
The association between oligoclonal IgG and measles virus antibodies present in cerebrospinal fluid samples or extracts of brain materials f … s. The dominating band of oligoclonal IgG appeared in all cases to represent antibodies against the nucleocapsid antigen. Bands of oligoclonal IgG with a certain antibody activity displayed a tendency to occupy a preferential position in the electropherogram. Antibodies against the hemolysin and the nucleocapsids had a relatively more cathodic position than an …