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1.
Cell Rep ; 38(10): 110503, 2022 03 08.
Article in English | MEDLINE | ID: covidwho-1705992

ABSTRACT

Natural killer (NK) cells are innate immune cells that contribute to host defense against virus infections. NK cells respond to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in vitro and are activated in patients with acute coronavirus disease 2019 (COVID-19). However, by which mechanisms NK cells detect SARS-CoV-2-infected cells remains largely unknown. Here, we show that the Non-structural protein 13 of SARS-CoV-2 encodes for a peptide that is presented by human leukocyte antigen E (HLA-E). In contrast with self-peptides, the viral peptide prevents binding of HLA-E to the inhibitory receptor NKG2A, thereby rendering target cells susceptible to NK cell attack. In line with these observations, NKG2A-expressing NK cells are particularly activated in patients with COVID-19 and proficiently limit SARS-CoV-2 replication in infected lung epithelial cells in vitro. Thus, these data suggest that a viral peptide presented by HLA-E abrogates inhibition of NKG2A+ NK cells, resulting in missing self-recognition.


Subject(s)
COVID-19 , Histocompatibility Antigens Class I , Killer Cells, Natural , Methyltransferases , NK Cell Lectin-Like Receptor Subfamily C , RNA Helicases , SARS-CoV-2 , Viral Nonstructural Proteins , COVID-19/immunology , Histocompatibility Antigens Class I/immunology , Humans , Killer Cells, Natural/immunology , Methyltransferases/immunology , NK Cell Lectin-Like Receptor Subfamily C/immunology , NK Cell Lectin-Like Receptor Subfamily C/metabolism , Peptides/metabolism , RNA Helicases/immunology , Viral Nonstructural Proteins/immunology
2.
Sci Rep ; 11(1): 22164, 2021 11 12.
Article in English | MEDLINE | ID: covidwho-1514425

ABSTRACT

The influenza A non-structural protein 1 (NS1) is known for its ability to hinder the synthesis of type I interferon (IFN) during viral infection. Influenza viruses lacking NS1 (ΔNS1) are under clinical development as live attenuated human influenza virus vaccines and induce potent influenza virus-specific humoral and cellular adaptive immune responses. Attenuation of ΔNS1 influenza viruses is due to their high IFN inducing properties, that limit their replication in vivo. This study demonstrates that pre-treatment with a ΔNS1 virus results in an antiviral state which prevents subsequent replication of homologous and heterologous viruses, preventing disease from virus respiratory pathogens, including SARS-CoV-2. Our studies suggest that ΔNS1 influenza viruses could be used for the prophylaxis of influenza, SARS-CoV-2 and other human respiratory viral infections, and that an influenza virus vaccine based on ΔNS1 live attenuated viruses would confer broad protection against influenza virus infection from the moment of administration, first by non-specific innate immune induction, followed by specific adaptive immunity.


Subject(s)
Influenza A virus/immunology , Influenza Vaccines/therapeutic use , Interferon Type I/immunology , Orthomyxoviridae Infections/prevention & control , Vaccines, Attenuated/therapeutic use , Viral Nonstructural Proteins/immunology , Adaptive Immunity , Animals , COVID-19/immunology , COVID-19/prevention & control , Chickens , Gene Deletion , Humans , Influenza A virus/genetics , Influenza Vaccines/genetics , Influenza Vaccines/immunology , Influenza, Human/immunology , Influenza, Human/prevention & control , Mice , Mice, Inbred C57BL , Orthomyxoviridae Infections/immunology , Vaccines, Attenuated/genetics , Vaccines, Attenuated/immunology , Viral Nonstructural Proteins/genetics
4.
Sci Adv ; 6(28): eabb8097, 2020 07.
Article in English | MEDLINE | ID: covidwho-1388430

ABSTRACT

The prevalence of respiratory illness caused by the novel SARS-CoV-2 virus associated with multiple organ failures is spreading rapidly because of its contagious human-to-human transmission and inadequate globalhealth care systems. Pharmaceutical repurposing, an effective drug development technique using existing drugs, could shorten development time and reduce costs compared to those of de novo drug discovery. We carried out virtual screening of antiviral compounds targeting the spike glycoprotein (S), main protease (Mpro), and the SARS-CoV-2 receptor binding domain (RBD)-angiotensin-converting enzyme 2 (ACE2) complex of SARS-CoV-2. PC786, an antiviral polymerase inhibitor, showed enhanced binding affinity to all the targets. Furthermore, the postfusion conformation of the trimeric S protein RBD with ACE2 revealed conformational changes associated with PC786 drug binding. Exploiting immunoinformatics to identify T cell and B cell epitopes could guide future experimental studies with a higher probability of discovering appropriate vaccine candidates with fewer experiments and higher reliability.


Subject(s)
Antiviral Agents/pharmacology , Betacoronavirus/immunology , Coronavirus Infections/prevention & control , Cysteine Endopeptidases/chemistry , Drug Design , Pandemics/prevention & control , Peptidyl-Dipeptidase A/chemistry , Pneumonia, Viral/prevention & control , Spike Glycoprotein, Coronavirus/chemistry , Viral Nonstructural Proteins/chemistry , Angiotensin-Converting Enzyme 2 , Benzamides , Benzazepines , Betacoronavirus/drug effects , Betacoronavirus/metabolism , Binding Sites , COVID-19 , Coronavirus 3C Proteases , Coronavirus Infections/immunology , Coronavirus Infections/virology , Cysteine Endopeptidases/immunology , Cysteine Endopeptidases/metabolism , Drug Evaluation, Preclinical , Epitopes, B-Lymphocyte/drug effects , Epitopes, B-Lymphocyte/immunology , Epitopes, T-Lymphocyte/drug effects , Epitopes, T-Lymphocyte/immunology , Humans , Molecular Docking Simulation , Peptidyl-Dipeptidase A/immunology , Peptidyl-Dipeptidase A/metabolism , Pneumonia, Viral/immunology , Pneumonia, Viral/virology , Protein Binding , Protein Conformation , Protein Domains , Protein Interaction Domains and Motifs , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/metabolism , Spiro Compounds/pharmacology , Viral Nonstructural Proteins/immunology , Viral Nonstructural Proteins/metabolism
5.
Signal Transduct Target Ther ; 5(1): 221, 2020 10 06.
Article in English | MEDLINE | ID: covidwho-1387195
7.
Signal Transduct Target Ther ; 6(1): 304, 2021 08 17.
Article in English | MEDLINE | ID: covidwho-1361622

ABSTRACT

A comprehensive analysis of the humoral immune response to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is essential in understanding COVID-19 pathogenesis and developing antibody-based diagnostics and therapy. In this work, we performed a longitudinal analysis of antibody responses to SARS-CoV-2 proteins in 104 serum samples from 49 critical COVID-19 patients using a peptide-based SARS-CoV-2 proteome microarray. Our data show that the binding epitopes of IgM and IgG antibodies differ across SARS-CoV-2 proteins and even within the same protein. Moreover, most IgM and IgG epitopes are located within nonstructural proteins (nsps), which are critical in inactivating the host's innate immune response and enabling SARS-CoV-2 replication, transcription, and polyprotein processing. IgM antibodies are associated with a good prognosis and target nsp3 and nsp5 proteases, whereas IgG antibodies are associated with high mortality and target structural proteins (Nucleocapsid, Spike, ORF3a). The epitopes targeted by antibodies in patients with a high mortality rate were further validated using an independent serum cohort (n = 56) and using global correlation mapping analysis with the clinical variables that are associated with COVID-19 severity. Our data provide fundamental insight into humoral immunity during SARS-CoV-2 infection. SARS-CoV-2 immunogenic epitopes identified in this work could also help direct antibody-based COVID-19 treatment and triage patients.


Subject(s)
Antibodies, Viral/immunology , COVID-19/immunology , Immunity, Humoral , SARS-CoV-2/immunology , Viral Nonstructural Proteins/immunology , COVID-19/mortality , Critical Illness , Disease-Free Survival , Epitopes/immunology , Female , Humans , Immunoglobulin G/immunology , Immunoglobulin M/immunology , Male , Protein Array Analysis , Survival Rate
8.
Emerg Microbes Infect ; 10(1): 1626-1637, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1348038

ABSTRACT

Coronaviruses (CoVs) can infect a variety of hosts, including humans, livestock and companion animals, and pose a serious threat to human health and the economy. The current COVID-19 pandemic, which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has killed millions of people. Unfortunately, effective treatments for CoVs infection are still lacking, suggesting the importance of coronavirus vaccines. Our previous work showed that CoV nonstuctural protein 14 (nsp14) functions as (guanine-N7)-methyltransferase (N7-MTase), which is involved in RNA cap formation. Moreover, we found that N7-MTase is well conserved among different CoVs and is a universal target for developing antivirals against CoVs. Here, we show that N7-MTase of CoVs can be an ideal target for designing live attenuated vaccines. Using murine hepatitis virus strain A59 (MHV-A59), a representative and well-studied model of coronaviruses, we constructed N7-MTase-deficient recombinant MHV D330A and Y414A. These two mutants are highly attenuated in mice and exhibit similar replication efficiency to the wild-type (WT) virus in the cell culture. Furthermore, a single dose immunization of D330A or Y414A can induce long-term humoral immune responses and robust CD4+ and CD8+ T cell responses, which can provide full protection against the challenge of a lethal-dose of MHV-A59. Collectively, this study provides an ideal strategy to design live attenuated vaccines for coronavirus by abolishing viral RNA N7-MTase activity. This approach may apply to other RNA viruses that encode their own conservative viral N7-methyltransferase.


Subject(s)
COVID-19 Vaccines/immunology , COVID-19/prevention & control , SARS-CoV-2/immunology , Vaccines, Attenuated/immunology , Animals , COVID-19 Vaccines/administration & dosage , Cytokines/biosynthesis , Humans , Immunity, Cellular , Immunity, Humoral , Immunogenicity, Vaccine , Interferon Type I/biosynthesis , Male , Mice , Mutation , Vaccines, Attenuated/administration & dosage , Viral Nonstructural Proteins/genetics , Viral Nonstructural Proteins/immunology
9.
PLoS One ; 16(7): e0253364, 2021.
Article in English | MEDLINE | ID: covidwho-1315884

ABSTRACT

Of the 16 non-structural proteins (Nsps) encoded by SARS CoV-2, Nsp3 is the largest and plays important roles in the viral life cycle. Being a large, multidomain, transmembrane protein, Nsp3 has been the most challenging Nsp to characterize. Encoded within Nsp3 is the papain-like protease domain (PLpro) that cleaves not only the viral polypeptide but also K48-linked polyubiquitin and the ubiquitin-like modifier, ISG15, from host cell proteins. We here compare the interactors of PLpro and Nsp3 and find a largely overlapping interactome. Intriguingly, we find that near full length Nsp3 is a more active protease compared to the minimal catalytic domain of PLpro. Using a MALDI-TOF based assay, we screen 1971 approved clinical compounds and identify five compounds that inhibit PLpro with IC50s in the low micromolar range but showed cross reactivity with other human deubiquitinases and had no significant antiviral activity in cellular SARS-CoV-2 infection assays. We therefore looked for alternative methods to block PLpro activity and engineered competitive nanobodies that bind to PLpro at the substrate binding site with nanomolar affinity thus inhibiting the enzyme. Our work highlights the importance of studying Nsp3 and provides tools and valuable insights to investigate Nsp3 biology during the viral infection cycle.


Subject(s)
Antiviral Agents/pharmacology , Protease Inhibitors/pharmacology , RNA-Dependent RNA Polymerase/antagonists & inhibitors , Single-Chain Antibodies/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , A549 Cells , Antigen-Antibody Complex , Humans , Inhibitory Concentration 50 , RNA-Dependent RNA Polymerase/immunology , RNA-Dependent RNA Polymerase/metabolism , Single-Chain Antibodies/immunology , Viral Nonstructural Proteins/immunology , Viral Nonstructural Proteins/metabolism
10.
Int J Mol Sci ; 22(13)2021 Jun 26.
Article in English | MEDLINE | ID: covidwho-1304664

ABSTRACT

Hepatitis C virus (HCV) is one of the main triggers of chronic liver disease. Despite tremendous progress in the HCV field, there is still no vaccine against this virus. Potential vaccines can be based on its recombinant proteins. To increase the humoral and, especially, cellular immune response to them, more effective adjuvants are needed. Here, we evaluated a panel of compounds as potential adjuvants using the HCV NS5B protein as an immunogen. These compounds included inhibitors of polyamine biosynthesis and urea cycle, the mTOR pathway, antioxidants, and cellular receptors. A pronounced stimulation of cell proliferation and interferon-γ (IFN-γ) secretion in response to concanavalin A was shown for antioxidant N-acetylcysteine (NAC), polyamine biosynthesis inhibitor 2-difluoromethylornithine (DFMO), and TLR9 agonist CpG ODN 1826 (CpG). Their usage during the immunization of mice with the recombinant NS5B protein significantly increased antibody titers, enhanced lymphocyte proliferation and IFN-γ production. NAC and CpG decreased relative Treg numbers; CpG increased the number of myeloid-derived suppressor cells (MDSCs), whereas neither NAC nor DFMO affected MDSC counts. NAC and DFMO suppressed NO and interleukin 10 (IL-10) production by splenocytes, while DFMO increased the levels of IL-12. This is the first evidence of immunomodulatory activity of NAC and DFMO during prophylactic immunization against infectious diseases.


Subject(s)
Acetylcysteine/pharmacology , Adjuvants, Immunologic/pharmacology , Eflornithine/pharmacology , Hepatitis C/immunology , Immunity, Active/drug effects , Viral Nonstructural Proteins/immunology , Animals , Cell Proliferation , Cells, Cultured , Female , Immunogenicity, Vaccine/drug effects , Interferon-gamma/metabolism , Interleukin-10/metabolism , Interleukin-12/metabolism , Mice , Mice, Inbred DBA , Myeloid-Derived Suppressor Cells/drug effects , Myeloid-Derived Suppressor Cells/immunology , Nitric Oxide/metabolism , Oligodeoxyribonucleotides/pharmacology , T-Lymphocytes, Regulatory/drug effects , T-Lymphocytes, Regulatory/immunology , Viral Hepatitis Vaccines/immunology
11.
Cell Rep ; 36(2): 109391, 2021 07 13.
Article in English | MEDLINE | ID: covidwho-1303454

ABSTRACT

The immunogenicity of the SARS-CoV-2 proteome is largely unknown, especially for non-structural proteins and accessory proteins. In this study, we collect 2,360 COVID-19 sera and 601 control sera. We analyze these sera on a protein microarray with 20 proteins of SARS-CoV-2, building an antibody response landscape for immunoglobulin (Ig)G and IgM. Non-structural proteins and accessory proteins NSP1, NSP7, NSP8, RdRp, ORF3b, and ORF9b elicit prevalent IgG responses. The IgG patterns and dynamics of non-structural/accessory proteins are different from those of the S and N proteins. The IgG responses against these six proteins are associated with disease severity and clinical outcome, and they decline sharply about 20 days after symptom onset. In non-survivors, a sharp decrease of IgG antibodies against S1 and N proteins before death is observed. The global antibody responses to non-structural/accessory proteins revealed here may facilitate a deeper understanding of SARS-CoV-2 immunology.


Subject(s)
COVID-19/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Viral Nonstructural Proteins/immunology , Viral Regulatory and Accessory Proteins/immunology , Adult , Aged , Antibodies, Viral/immunology , Antibody Formation , Humans , Immunoglobulin G/immunology , Immunoglobulin M/immunology , Male , Middle Aged , Protein Array Analysis
12.
PLoS One ; 16(6): e0253089, 2021.
Article in English | MEDLINE | ID: covidwho-1282298

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a devastating global pandemic, infecting over 43 million people and claiming over 1 million lives, with these numbers increasing daily. Therefore, there is urgent need to understand the molecular mechanisms governing SARS-CoV-2 pathogenesis, immune evasion, and disease progression. Here, we show that SARS-CoV-2 can block IRF3 and NF-κB activation early during virus infection. We also identify that the SARS-CoV-2 viral proteins NSP1 and NSP13 can block interferon activation via distinct mechanisms. NSP1 antagonizes interferon signaling by suppressing host mRNA translation, while NSP13 downregulates interferon and NF-κB promoter signaling by limiting TBK1 and IRF3 activation, as phospho-TBK1 and phospho-IRF3 protein levels are reduced with increasing levels of NSP13 protein expression. NSP13 can also reduce NF-κB activation by both limiting NF-κB phosphorylation and nuclear translocation. Last, we also show that NSP13 binds to TBK1 and downregulates IFIT1 protein expression. Collectively, these data illustrate that SARS-CoV-2 bypasses multiple innate immune activation pathways through distinct mechanisms.


Subject(s)
Adaptor Proteins, Signal Transducing/immunology , COVID-19/immunology , Cell Nucleus/immunology , Interferon Regulatory Factor-3/immunology , RNA-Binding Proteins/immunology , SARS-CoV-2/immunology , Signal Transduction/immunology , Viral Nonstructural Proteins/immunology , Active Transport, Cell Nucleus/genetics , Active Transport, Cell Nucleus/immunology , Adaptor Proteins, Signal Transducing/genetics , COVID-19/genetics , Cell Nucleus/genetics , HeLa Cells , Humans , Interferon Regulatory Factor-3/genetics , NF-kappa B/genetics , NF-kappa B/immunology , Phosphorylation/genetics , Phosphorylation/immunology , /immunology , RNA-Binding Proteins/genetics , SARS-CoV-2/genetics , Signal Transduction/genetics , Viral Nonstructural Proteins/genetics
13.
Proc Natl Acad Sci U S A ; 118(24)2021 06 15.
Article in English | MEDLINE | ID: covidwho-1246477

ABSTRACT

The ongoing COVID-19 pandemic has caused an unprecedented global health crisis. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of COVID-19. Subversion of host protein synthesis is a common strategy that pathogenic viruses use to replicate and propagate in their host. In this study, we show that SARS-CoV-2 is able to shut down host protein synthesis and that SARS-CoV-2 nonstructural protein NSP14 exerts this activity. We show that the translation inhibition activity of NSP14 is conserved in human coronaviruses. NSP14 is required for virus replication through contribution of its exoribonuclease (ExoN) and N7-methyltransferase (N7-MTase) activities. Mutations in the ExoN or N7-MTase active sites of SARS-CoV-2 NSP14 abolish its translation inhibition activity. In addition, we show that the formation of NSP14-NSP10 complex enhances translation inhibition executed by NSP14. Consequently, the translational shutdown by NSP14 abolishes the type I interferon (IFN-I)-dependent induction of interferon-stimulated genes (ISGs). Together, we find that SARS-CoV-2 shuts down host innate immune responses via a translation inhibitor, providing insights into the pathogenesis of SARS-CoV-2.


Subject(s)
COVID-19/immunology , Exoribonucleases/immunology , Immune Evasion , Immunity, Innate , Protein Biosynthesis/immunology , SARS-CoV-2/immunology , Viral Nonstructural Proteins/immunology , Animals , Chlorocebus aethiops , Humans , Vero Cells
14.
Cell Rep ; 35(7): 109126, 2021 05 18.
Article in English | MEDLINE | ID: covidwho-1222854

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) evades most innate immune responses but may still be vulnerable to some. Here, we systematically analyze the impact of SARS-CoV-2 proteins on interferon (IFN) responses and autophagy. We show that SARS-CoV-2 proteins synergize to counteract anti-viral immune responses. For example, Nsp14 targets the type I IFN receptor for lysosomal degradation, ORF3a prevents fusion of autophagosomes and lysosomes, and ORF7a interferes with autophagosome acidification. Most activities are evolutionarily conserved. However, SARS-CoV-2 Nsp15 antagonizes IFN signaling less efficiently than the orthologs of closely related RaTG13-CoV and SARS-CoV-1. Overall, SARS-CoV-2 proteins counteract autophagy and type I IFN more efficiently than type II or III IFN signaling, and infection experiments confirm potent inhibition by IFN-γ and -λ1. Our results define the repertoire and selected mechanisms of SARS-CoV-2 innate immune antagonists but also reveal vulnerability to type II and III IFN that may help to develop safe and effective anti-viral approaches.


Subject(s)
COVID-19/virology , SARS-CoV-2/immunology , Viral Proteins/immunology , Animals , Antiviral Agents/pharmacology , Autophagosomes/immunology , Autophagy/immunology , COVID-19/immunology , Cell Line , Chlorocebus aethiops , Exoribonucleases/immunology , HEK293 Cells , HeLa Cells , Humans , Immune Evasion , Immunity, Innate , Interferon Type I/metabolism , Interferons/metabolism , Receptor, Interferon alpha-beta/antagonists & inhibitors , Receptor, Interferon alpha-beta/immunology , SARS-CoV-2/pathogenicity , Vero Cells , Viral Nonstructural Proteins/immunology
15.
BMC Bioinformatics ; 22(1): 182, 2021 Apr 08.
Article in English | MEDLINE | ID: covidwho-1175288

ABSTRACT

BACKGROUND: The rapid spread of the COVID-19 demands immediate response from the scientific communities. Appropriate countermeasures mean thoughtful and educated choice of viral targets (epitopes). There are several articles that discuss such choices in the SARS-CoV-2 proteome, other focus on phylogenetic traits and history of the Coronaviridae genome/proteome. However none consider viral protein low complexity regions (LCRs). Recently we created the first methods that are able to compare such fragments. RESULTS: We show that five low complexity regions (LCRs) in three proteins (nsp3, S and N) encoded by the SARS-CoV-2 genome are highly similar to regions from human proteome. As many as 21 predicted T-cell epitopes and 27 predicted B-cell epitopes overlap with the five SARS-CoV-2 LCRs similar to human proteins. Interestingly, replication proteins encoded in the central part of viral RNA are devoid of LCRs. CONCLUSIONS: Similarity of SARS-CoV-2 LCRs to human proteins may have implications on the ability of the virus to counteract immune defenses. The vaccine targeted LCRs may potentially be ineffective or alternatively lead to autoimmune diseases development. These findings are crucial to the process of selection of new epitopes for drugs or vaccines which should omit such regions.


Subject(s)
Proteome , SARS-CoV-2/genetics , Sequence Homology , COVID-19 Vaccines , Coronavirus Nucleocapsid Proteins/immunology , Epitopes, B-Lymphocyte/immunology , Epitopes, T-Lymphocyte/immunology , Humans , Phosphoproteins/immunology , Phylogeny , RNA-Dependent RNA Polymerase/immunology , Risk Factors , Spike Glycoprotein, Coronavirus/immunology , Viral Nonstructural Proteins/immunology
16.
Virol J ; 18(1): 54, 2021 03 11.
Article in English | MEDLINE | ID: covidwho-1133601

ABSTRACT

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic remains ongoing around the world, including in areas where dengue is endemic. Dengue and COVID-19, to some extent, have similar clinical and laboratory features, which can lead to misdiagnosis, delayed treatment and patient's isolation. The use of rapid diagnostic tests (RDT) is easy and convenient for fast diagnosis, however there may be issues with cross-reactivity with antibodies for other pathogens. METHODS: We assessed the possibility of cross-reactivity between SARS-CoV-2 and dengue antibodies by: (1) testing five brands of COVID-19 IgG / IgM RDTs on 60 RT-PCR-confirmed dengue samples; (2) testing 95 RT-PCR-confirmed COVID-19 samples on dengue RDT; and (3) testing samples positive for COVID-19 IgG and/or IgM on dengue RDT. RESULTS: We observed a high specificity across all five brands of COVID-19 RDTs, ranging from 98.3 to 100%. Out of the confirmed COVID-19 samples, one patient tested positive for dengue IgM only, another tested positive for dengue IgG only. One patient tested positive for dengue IgG, IgM, and NS1, suggesting a co-infection. In COVID-19 IgG and/or IgM samples, 6.3% of COVID-19 IgG-positive samples also tested positive for dengue IgG, while 21.1% of COVID-19 IgM-positive samples also tested positive for dengue IgG. CONCLUSION: Despite the high specificity of the COVID-19 RDT, we observed cross-reactions and false-positive results between dengue and COVID-19. Dengue and COVID-19 co-infection was also found. Health practitioners in dengue endemic areas should be careful when using antibody RDT for the diagnosis of dengue during the COVID-19 pandemic to avoid misdiagnosis.


Subject(s)
Antibodies, Viral/immunology , COVID-19/diagnosis , Cross Reactions/immunology , Dengue Virus/immunology , Dengue/diagnosis , SARS-CoV-2/immunology , Adolescent , Adult , Child , Diagnosis, Differential , Diagnostic Tests, Routine , False Positive Reactions , Female , Humans , Immunoglobulin A/immunology , Immunoglobulin G/immunology , Immunoglobulin M/immunology , Indonesia , Male , Middle Aged , Sensitivity and Specificity , Viral Nonstructural Proteins/immunology , Young Adult
17.
PLoS Pathog ; 17(2): e1008690, 2021 02.
Article in English | MEDLINE | ID: covidwho-1105832

ABSTRACT

Cytoplasmic stress granules (SGs) are generally triggered by stress-induced translation arrest for storing mRNAs. Recently, it has been shown that SGs exert anti-viral functions due to their involvement in protein synthesis shut off and recruitment of innate immune signaling intermediates. The largest RNA viruses, coronaviruses, impose great threat to public safety and animal health; however, the significance of SGs in coronavirus infection is largely unknown. Infectious Bronchitis Virus (IBV) is the first identified coronavirus in 1930s and has been prevalent in poultry farm for many years. In this study, we provided evidence that IBV overcomes the host antiviral response by inhibiting SGs formation via the virus-encoded endoribonuclease nsp15. By immunofluorescence analysis, we observed that IBV infection not only did not trigger SGs formation in approximately 80% of the infected cells, but also impaired the formation of SGs triggered by heat shock, sodium arsenite, or NaCl stimuli. We further demonstrated that the intrinsic endoribonuclease activity of nsp15 was responsible for the interference of SGs formation. In fact, nsp15-defective recombinant IBV (rIBV-nsp15-H238A) greatly induced the formation of SGs, along with accumulation of dsRNA and activation of PKR, whereas wild type IBV failed to do so. Consequently, infection with rIBV-nsp15-H238A strongly triggered transcription of IFN-ß which in turn greatly affected rIBV-nsp15-H238A replication. Further analysis showed that SGs function as an antiviral hub, as demonstrated by the attenuated IRF3-IFN response and increased production of IBV in SG-defective cells. Additional evidence includes the aggregation of pattern recognition receptors (PRRs) and signaling intermediates to the IBV-induced SGs. Collectively, our data demonstrate that the endoribonuclease nsp15 of IBV interferes with the formation of antiviral hub SGs by regulating the accumulation of viral dsRNA and by antagonizing the activation of PKR, eventually ensuring productive virus replication. We further demonstrated that nsp15s from PEDV, TGEV, SARS-CoV, and SARS-CoV-2 harbor the conserved function to interfere with the formation of chemically-induced SGs. Thus, we speculate that coronaviruses employ similar nsp15-mediated mechanisms to antagonize the host anti-viral SGs formation to ensure efficient virus replication.


Subject(s)
COVID-19/virology , Cytoplasmic Granules/metabolism , Endoribonucleases/immunology , Endoribonucleases/metabolism , SARS-CoV-2/physiology , Viral Nonstructural Proteins/immunology , Viral Nonstructural Proteins/metabolism , COVID-19/metabolism , Cell Line , Coronavirus/immunology , Cytoplasmic Granules/immunology , Cytoplasmic Granules/virology , Humans , Interferon-beta/immunology , Interferon-beta/metabolism , SARS-CoV-2/metabolism , Signal Transduction , Virus Replication/physiology
18.
Curr Mol Med ; 22(1): 50-66, 2022.
Article in English | MEDLINE | ID: covidwho-1099962

ABSTRACT

The proteins of coronavirus are classified as non-structural, structural, and accessory. There are 16 non-structural viral proteins besides their precursors (1a and 1ab polyproteins). The non-structural proteins are named nsp1 to nsp16, and they act as enzymes, coenzymes, and binding proteins to facilitate the replication, transcription, and translation of the virus. The structural proteins are bound to the RNA in the nucleocapsid (N- protein) or to the lipid bilayer membrane of the viral envelope. The lipid bilayer proteins include the membrane protein (M), an envelope protein (E), and spike protein (S). Besides their role as structural proteins, they are essential for the host cells' binding and invasion. The SARS-CoV-2 contains six accessory proteins which participate in the viral replication, assembly and virus-host interactions. The SARS-CoV-2 accessory proteins are orf3a, orf6, orf7a, orf7b, orf8, and orf10. The functions of the SARS-CoV-2 are not well known, while the functions of their corresponding proteins in SARS-CoV are either well known or poorly studied. Recently, the Oxford University and Astrazeneca, Pfizer and BioNTech have made SARS-CoV-2 vaccines by targeting the spike protein gene. The US Food and Drug Administration (FDA) and the health authorities of the United Kingdom have approved and started conducting vaccinations using the Pfizer and BioNTech mRNA vaccine. Also, The FDA of the USA has approved the use of two monoclonal antibodies produced by Regeneron pharmaceuticals to target the spike protein for treating COVID-19. The SARS-CoV-2 proteins can be used for the diagnosis, as drug targets and in vaccination trials for COVID-19. In future COVID-19 research, more efforts should be made to elaborate the functions and structure of the SARS-CoV- 2 proteins so as to use them as targets for COVID-19 drugs and vaccines. Special attention should be paid to extensive research on the SARS-CoV-2 nsp3, orf8, and orf10.


Subject(s)
Antiviral Agents/pharmacology , COVID-19 Vaccines , COVID-19/prevention & control , SARS-CoV-2/chemistry , Viral Proteins/drug effects , Viral Proteins/immunology , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/therapeutic use , Antibodies, Viral/immunology , Antibodies, Viral/therapeutic use , Antigens, Viral/immunology , COVID-19/drug therapy , COVID-19/immunology , Drug Design , Humans , Immunotherapy , SARS-CoV-2/drug effects , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Viral Nonstructural Proteins/drug effects , Viral Nonstructural Proteins/immunology , Viral Nonstructural Proteins/physiology , Viral Proteins/physiology , Viral Regulatory and Accessory Proteins/drug effects , Viral Regulatory and Accessory Proteins/immunology , Viral Regulatory and Accessory Proteins/physiology , Viral Structural Proteins/drug effects , Viral Structural Proteins/immunology , Viral Structural Proteins/physiology
19.
Cell Host Microbe ; 29(3): 489-502.e8, 2021 03 10.
Article in English | MEDLINE | ID: covidwho-1064930

ABSTRACT

The SARS-CoV-2 virus, the causative agent of COVID-19, is undergoing constant mutation. Here, we utilized an integrative approach combining epidemiology, virus genome sequencing, clinical phenotyping, and experimental validation to locate mutations of clinical importance. We identified 35 recurrent variants, some of which are associated with clinical phenotypes related to severity. One variant, containing a deletion in the Nsp1-coding region (Δ500-532), was found in more than 20% of our sequenced samples and associates with higher RT-PCR cycle thresholds and lower serum IFN-ß levels of infected patients. Deletion variants in this locus were found in 37 countries worldwide, and viruses isolated from clinical samples or engineered by reverse genetics with related deletions in Nsp1 also induce lower IFN-ß responses in infected Calu-3 cells. Taken together, our virologic surveillance characterizes recurrent genetic diversity and identified mutations in Nsp1 of biological and clinical importance, which collectively may aid molecular diagnostics and drug design.


Subject(s)
COVID-19/immunology , COVID-19/virology , Interferon Type I/immunology , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Viral Nonstructural Proteins/genetics , A549 Cells , Adolescent , Adult , Aged , Aged, 80 and over , Animals , Base Sequence , COVID-19/blood , Cell Line , Child , Child, Preschool , Chlorocebus aethiops , Female , Gene Deletion , Genomics , HEK293 Cells , Humans , Infant , Interferon Type I/blood , Interferon-beta/blood , Interferon-beta/metabolism , Male , Middle Aged , Molecular Epidemiology , Reverse Genetics , Vero Cells , Viral Nonstructural Proteins/immunology , Young Adult
20.
Virology ; 556: 73-78, 2021 04.
Article in English | MEDLINE | ID: covidwho-1049897

ABSTRACT

The need to stem the current outbreak of SARS-CoV-2 responsible for COVID-19 is driving the search for inhibitors that will block coronavirus replication and pathogenesis. The coronavirus 3C-like protease (3CLpro) encoded in the replicase polyprotein is an attractive target for antiviral drug development because protease activity is required for generating a functional replication complex. Reagents that can be used to screen for protease inhibitors and for identifying the replicase products of SARS-CoV-2 are urgently needed. Here we describe a luminescence-based biosensor assay for evaluating small molecule inhibitors of SARS-CoV-2 3CLpro/main protease. We also document that a polyclonal rabbit antiserum developed against SARS-CoV 3CLpro cross reacts with the highly conserved 3CLpro of SARS-CoV-2. These reagents will facilitate the pre-clinical evaluation of SARS-CoV-2 protease inhibitors.


Subject(s)
Biosensing Techniques/methods , Coronavirus 3C Proteases/metabolism , Immune Sera/immunology , Luciferases/metabolism , SARS-CoV-2/metabolism , Animals , Antiviral Agents/pharmacology , Coronavirus 3C Proteases/antagonists & inhibitors , Coronavirus 3C Proteases/genetics , Coronavirus 3C Proteases/immunology , Cross Reactions , Luciferases/genetics , Protease Inhibitors/pharmacology , Rabbits , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/metabolism , SARS Virus/immunology , SARS Virus/metabolism , SARS-CoV-2/drug effects , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Viral Nonstructural Proteins/genetics , Viral Nonstructural Proteins/immunology , Viral Nonstructural Proteins/metabolism , Virus Replication/drug effects
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