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A safe, cost-effective, and high-throughput SARS-CoV-2 antigen capture ELISA suitable for large-scale screening in low-resource settings.

Diagnostics employing multiple modalities have been essential for controlling and managing COVID-19, caused by SARS-CoV-2. However, scaling up Reverse Transcription-Quantitative Polymerase Chain Reaction (RT-qPCR), the gold standard for SARS-CoV-2 detection, remains challenging in low and middle-income countries. Cost-effective and high-throughput alternatives like enzyme-linked immunosorbent assay (ELISA) could address this issue. We developed an in-house SARS-CoV-2 nucleocapsid capture ELISA, and validated on 271 nasopharyngeal swab samples from humans (n = 252), bovines (n = 10), and dogs (…

Symptomatology and IgG Levels before and after SARS-CoV-2 Omicron Breakthrough Infections in Vaccinated Individuals.

(1) Background: After the COVID-19 pandemic, there is concern regarding the immunity of the population to SARS-CoV-2 variants, particularly the Omicron variant and its sub-lineages. (2) Methods: The study involved analyzing the immune response and symptomatology of 27 vaccinated individuals who were subsequently infected by Omicron sub-lineages. Blood samples were collected for serological analysis, including the detection of IgG antibodies reactive to the Nucleocapsid (N) and Spike (S) antigens of SARS-CoV-2. Additionally, participants were interviewed to assess the intensity of symptoms duri…

Microarray-Based Detection of Antibodies against SARS-CoV-2 Proteins, Common Respiratory Viruses and Type I Interferons.

A microarray-based assay to detect IgG and IgM antibodies against betacoronaviruses (SARS-CoV-2, SARS, MERS, OC43, and HKU1), other respirat … bodies against more than two different viruses. Cross-reactivity between IgG against the SARS-CoV-2 nucleocapsid and IgG against the OC43 and HKU1 spike proteins was observed, resulting in positive signals for the SARS-CoV-2 nucleocapsid in prepandemic samples from patients with autoimmune endocrine disorders. The presence of IgG against the SARS-CoV-2 nucleoc …

UBE2O, a host ubiquitin-conjugating enzyme, is a key regulator of hepatitis B virus maturation and egress.

A critical step in Hepatitis B virus (HBV) maturation and egress is the ubiquitination of the capsid/core protein (HBc), which enables its recognition by the endosomal sorting complex required for transport (ESCRT) machinery and recruitment to multivesicular bodies (MVBs). This study investigates the role of UBE2O, an atypical E2 ubiquitin-conjugating enzyme with intrinsic E3 ligase activity, in nucleocapsid assembly and virion egress. Loss of UBE2O in HBV-infected primary human hepatocytes (PHH) and HepG2-NTCP cells led to a reduction in viral replication, as evidenced by decreased levels of …

VP40, the matrix protein of Marburg virus, is associated with membranes of the late endosomal compartment.

Localization of VP40 in Marburg virus (MBGV)-infected cells was studied by using immunofluorescence and immunoelectron microscopic analysis. VP40 was detected in association with nucleocapsid structures, present in viral inclusions and at sites of virus budding. Additionally, VP40 was identified in the foci of virus-induced membrane proliferation and in intracellular membrane clusters which had the appearance of multivesicular bodies (MVBs). VP40-containing MVBs were free of nucleocapsids. When analyzed by immunogold labeling, the concentration of VP40 in MVBs was six times higher than in nucl…

Vaccination and hybrid immunity is associated with SARS-CoV-2 protection but not shedding duration in rural Guatemalan households.

BACKGROUND: Essential agricultural workers in Central America and their households faced a high force of infection during the COVID-19 pande … ding. We selected 119 SARS-CoV-2 PCR-positive individuals and 101 month-matched controls to measure nucleocapsid IgG and Omicron neutralizing antibody (NAb) titers. RESULTS: Compared to uninfected controls, SARS-CoV-2 cases were more frequently female (60.5% vs 48.5%, p=0.08), had fewer vaccine doses (p=0.07), and were less likely to have hybrid immunity (p=0 …

Monitoring SARS CoV-2 antibodies positivity in healthcare workers after inactivated CoronaVac® vaccine.

INTRODUCTION: In this study, we aimed to monitor anti-spike and anti-nucleocapsid antibodies positivity in healthcare workers (HCWs) vaccinated with two doses of inactivated CoronaVac® (Sinovac, China) vaccine. METHODS: Overall, 242 volunteer HCWs were included. Of the participants, 193 were HCWs without history of prior documented COVID-19 (Group 1), while 49 had history of prior documented COVID-19 before vaccination (Group 2). The participants were followed up for SARS-CoV-2 antibodies positivity at four different blood sampling time points (immediately before the second vaccine dose and a…

COVID-19-Related Chronic Bilateral Dacryoadenitis: A Clinicopathological Study.

IMPORTANCE: Pathological features of ophthalmic aftereffects of COVID-19 are important for new insight in treating patients. OBJECTIVE: To examine the expression of SARS-CoV-2 nucleocapsid protein and angiotensin-converting enzyme 2 (ACE2) in lacrimal gland tissues of a patient with COVID-19 and a patient without COVID-19. DESIGN, SETTING, AND PARTICIPANTS: In this retrospective case-control study, the case of a 35-year-old woman with positive test results for SARS-CoV-2 who had had lacrimal gland enlargements for 6 months was analyzed. A 43-year-old woman without COVID-19 who had idiopathic…

Emergence of SARS-CoV-2 subgenomic RNAs that enhance viral fitness and immune evasion.

Coronaviruses express their structural and accessory genes via a set of subgenomic RNAs, whose synthesis is directed by transcription regula … ved convergently in multiple lineages. The most frequent neo-TRS is within the coding region of the Nucleocapsid gene, and is present in virtually all viruses from the B.1.1 lineage, including the variants of concern Alpha, Gamma, Omicron and descendants thereof. Here, we demonstrate that this TRS leads to the expression of a novel subgenomic mRNA encoding a t …

Understanding the Omicron Variant Impact in Healthcare Workers: Insights from the Prospective COVID-19 Post-Immunization Serological Cohort in Munich (KoCo-Impf) on Risk Factors for Breakthrough and Reinfections.

This study analyzes immune responses to SARS-CoV-2 vaccination and infection, including asymptomatic cases, focusing on infection risks during the Omicron wave, particularly among high-risk healthcare workers. In the KoCo-Impf study, we monitored 6088 vaccinated participants in Munich aged 18 and above. From 13 May to 31 July 2022, 2351 participants were follow-uped. Logistic regression models evaluated primary, secondary, and breakthrough infections (BTIs). Roche Elecsys® Anti-SARS-CoV-2 assays detected prior infections (via anti-Nucleocapsid antibodies) and assessed vaccination/infection imp…

Effect of Neutralizing Monoclonal Antibody Treatment on Early Trajectories of Virologic and Immunologic Biomarkers in Patients Hospitalized With COVID-19.

BACKGROUND: Neutralizing monoclonal antibodies (nmAbs) failed to show clear benefit for hospitalized patients with coronavirus disease 2019 (COVID-19). Dynamics of virologic and immunologic biomarkers remain poorly understood. METHODS: Participants enrolled in the Therapeutics for Inpatients with COVID-19 trials were randomized to nmAb versus placebo. Longitudinal differences between treatment and placebo groups in levels of plasma nucleocapsid antigen (N-Ag), anti-nucleocapsid antibody, C-reactive protein, interleukin-6, and D-dimer at enrollment, day 1, 3, and 5 were estimated using linear …

Архитектурная организация и белковая структура внутриполосного синтеза вируса лимфоцита.

UNLABELELED: Аренавирусы существуют во всем мире и могут вызывать геморрагическую лихорадку и неврологические заболевания, примером чему служит зоонотические патогенные лимфоциты (LCMV). Сообщалось о структурах отдельных белков LCMV или их фрагментов, однако архитектурная организация и механизм сборки нуклеокапсида по-прежнему остаются неуловимыми. Важно отметить, что не была продемонстрирована структура белкового комплекса аренывирусного синтеза (гликопротеиновый комплекс, ГПК), которая присутствует на вирионе до синтеза, особенно с его интегральным устойчивым сигнальным пептидом (SSP), что п

Совпадение в аннотации оригинала
UNLABELLED: Arenaviruses exist globally and can cause hemorrhagic fever and neurological diseases, exemplified by the zoonotic pathogen lymphocytic choriomeningitis virus (LCMV). The structures of individual LCMV proteins or their fragments have been reported, but the architectural organization and the nucleocapsid assembly mechanism remain elusive. Importan…

Production of antigens expressed in Nicotiana benthamiana plant and Escherichia coli for the SARS-CoV-2 IgG antibody detection by ELISA.

The recent COVID-19 pandemic disclosed a critical shortage of diagnostic kits worldwide, emphasizing the urgency of utilizing all resources … teins included the truncated S1-N protein (spike protein N-terminus residues 12-316) and antigen N (nucleocapsid residues 37-402). Two other distinct SARS-CoV-2 antigens expressed in Escherichia coli were evaluated: QCoV9 chimeric antigen protein (spike protein residues 449-711 and nucleocapsid protein residues 160-406) and QCoV7 truncated antigen (nucleocapsi …

Characterization and in vitro assembly of tick-borne encephalitis virus C protein.

Tick-borne encephalitis virus (TBEV), a member of flaviviruses, represents a serious health threat by causing human encephalitis mainly in central and eastern Europe, Russia, and northeastern Asia. As no specific therapy is available, there is an urgent need to understand all steps of the TBEV replication cycle at the molecular level. One of the critical events is the packaging of flaviviral genomic RNA by TBEV C protein to form a nucleocapsid. We purified recombinant TBEV C protein and used a combination of physical-chemical approaches, such as size-exclusion chromatography, circular dichrois…

Generation and characterization of monoclonal antibodies against Rift Valley fever virus nucleoprotein.

Due to the unpredictable and explosive nature of Rift Valley fever (RVF) outbreaks, rapid and accurate diagnostic assays for low-resource settings are urgently needed. To improve existing diagnostic assays, monoclonal antibodies (MAbs) specific for the nucleocapsid protein of RVF virus (RVFV) were produced and characterized. Four IgG2a MAbs showed specific binding to denatured nucleocapsid protein, both from a recombinant source and from inactivated RVFV, in Western blot analysis and in an enzyme-linked immunosorbent assay (ELISA). Cross-reactivity with genetically related and non-related arbo…

Crystal structure of the rabies virus nucleoprotein-RNA complex.

Negative-strand RNA viruses condense their genome into a helical nucleoprotein-RNA complex, the nucleocapsid, which is packed into virions and serves as a template for the RNA-dependent RNA polymerase complex. The crystal structure of a recombinant rabies virus nucleoprotein-RNA complex, organized in an undecameric ring, has been determined at 3.5 angstrom resolution. Polymerization of the nucleoprotein is achieved by domain exchange between protomers, with flexible hinges allowing nucleocapsid formation. The two core domains of the nucleoprotein clamp around the RNA at their interface and shi…

Inclusion body myositis and paramyxoviruses.

Inclusion body myositis (IBM) is a distinct type of muscle disease. The characteristic electron microscopic findings, intranuclear or intracytoplasmic inclusions composed of microtubular filaments, morphologically resemble paramyxovirus nucleocapsids. These findings and the reported immunoreactivity of the inclusions with mumps virus antibodies have suggested that inclusion body myositis is a chronic virus infection. We analyzed skeletal muscle specimens from three patients with characteristic light microscopic features and electron microscopically verified inclusions of IBM by immunocytochemi…

Characterization of a mumps virus nucleocapsidlike particle.

The nucleocapsid protein (NP) of mumps virus (MuV), a paramyxovirus, was coexpressed with the phosphoprotein (P) in Escherichia coli. The NP and P proteins form a soluble complex containing RNA. Under a transmission electron microscope, the NP-RNA complex appears as a nucleocapsidlike ring that has a diameter of approximately 20 nm with 13 subunits. There is a piece of single-stranded RNA with a length of 78 nucleotides in the NP-RNA ring. Shorter RNA pieces are also visible. The MuV NP protein may provide weaker protection of the RNA than the NP protein of some other negative-strand RNA virus…

The Meaning of SARS-CoV-2 Antibodies in a Patient with a Systemic Reaction to the mRNA-1273 SARS-CoV-2 Vaccine after Previous Natural Immunization.

OBJECTIVES: There is limited experience regarding the meaning of SARS-CoV-2 antibodies after vaccination in patients with naturally acquired immunity. METHODS: We describe the case of a patient who received the first dose of the mRNA-1273 SARS-CoV-2 vaccine 6 months after his recovery from moderately severe COVID-19. RESULTS: Our patient had a positive nucleocapsid SARS-CoV-2 IgG/IgM titre with 78.7 multiple of cut-off indicating persistent humoral immune response 6 months after infection. After vaccination, he developed prolonged systemic symptoms (fever, fatigue, nausea, diarrhoea and myal…

Investigation about the surface structure of some viruses by the freeze-etching and freeze-drying methods.

An electronmicroscopic study of a suspension of Venezuelan equine encephalomyelitis (VEE) virus by freeze-drying and freeze-etching methods showed that glycoprotein peplomers are located on the surface of the lipoprotein shell. These peplomers are trimeric in shape and form a regular icosahedral surface lattice corresponding to T = 4. The modes of glycoproteins clustering for the two clones of VEE are different. Venezuelan equine encephalomyelitis (VEE) virus belongs to the alpha-viruses of the toga-virus family. Virions of VEE virus have the icosahedral nucleocapsid surrounded by a lipoprotei…