Identification of Conserved Epitopes in SARS-CoV-2 Spike and Nucleocapsid Protein

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel virus that first occurred in Wuhan in December 2019. The spike glycoproteins and nucleocapsid proteins are the most common targets for the development of vaccines and antiviral drugs. Objective: We herein analyze the rate of evolution along with the sequences of spike and nucleocapsid proteins in relation to the spatial locations of their epitopes, previously suggested to contribute to the immune response caused by SARS-CoV-2 infections. Methods: We compare homologous proteins of seven human coronaviruses: HCoV-229E, HCoV-OC43, SARS-CoV, HCoV-NL63, HCoV-HKU1, MERS-CoV, and SARS-CoV-2. We then focus on the local, structural order-disorder propensity of the protein regions where the SARS-CoV-2 epitopes are located. Results : We show that most of nucleocapsid protein epitopes overlap the RNA-binding and dimerization domains, and some of them are characterized by a low rate of evolutions. Similarly, spike protein epitopes are preferentially located in regions that are predicted to be ordered and well-conserved, in correspondence of the heptad repeats 1 and 2. Interestingly, both the receptor-binding motif to ACE2 and the fusion peptide of spike protein are characterized by a high rate of evolution. Conclusion: Our results provide evidence for conserved epitopes that might help develop broad-spectrum SARS-CoV-2 vaccines.

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Identification of conserved epitopes in SARS-CoV-2 spike and nucleocapsid protein

10.1101/2020.05.14.095133 ◽

2020 ◽

Cited By ~ 2

Author(s):

Sergio Forcelloni ◽

Anna Benedetti ◽

Maddalena Dilucca ◽

Andrea Giansanti

Keyword(s):

Nucleocapsid Protein ◽

Rna Binding ◽

Spike Protein ◽

Disease Spread ◽

Binding Motif ◽

T Cell Epitopes ◽

Nucleocapsid Proteins ◽

Structural Order ◽

Rates Of Evolution ◽

Human Coronaviruses

AbstractSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which first occurred in Wuhan (China) in December 2019, is a novel virus that causes a severe acute respiratory disease. The virus spike glycoproteins and nucleocapsid proteins are the main targets for the development of vaccines and antiviral drugs, to control the disease spread. We herein study the structural order-disorder propensity and the rates of evolution of these two proteins to characterize their B cell and T cell epitopes, previously suggested to contribute to immune response caused by SARS-CoV-2 infections. We first analyzed the rates of evolution along the sequences of spike and nucleocapsid proteins in relation to the spatial locations of their epitopes. For this purpose, we compared orthologs from seven human coronaviruses: SARS-CoV-2, SARS-CoV, MERS-CoV, HCoV-229E, HCoV-OC43, HCoV-NL63, and HCoV-HKU1. We then focus on the local, structural order-disorder propensities of the protein regions where the SARS-CoV-2 epitopes are located. We show that the vast majority of nucleocapsid protein epitopes overlap the RNA-binding and dimerization domains and some of them are characterized by low rates of evolutions. Similarly, spike protein epitopes are preferentially located in regions that are predicted to be ordered and well-conserved, in correspondence of the heptad repeats 1 and 2. Interestingly, both the receptor-binding motif to ACE2 and the fusion peptide of spike protein are characterized by high rates of evolution, probably to overcome host immunity. In conclusion, our results provide evidence for conserved epitopes that may help to develop long-lasting, broad-spectrum SARS-CoV-2 vaccines.

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Immunological imprinting of the antibody response in COVID-19 patients

Nature Communications ◽

10.1038/s41467-021-23977-1 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Teresa Aydillo ◽

Alexander Rombauts ◽

Daniel Stadlbauer ◽

Sadaf Aslam ◽

Gabriela Abelenda-Alonso ◽

...

Keyword(s):

Immune Response ◽

Severe Acute Respiratory Syndrome ◽

Antibody Response ◽

Humoral Immune Response ◽

Nucleocapsid Protein ◽

Spike Protein ◽

Ongoing Research ◽

Variable Regions ◽

Humoral Immune ◽

Human Coronaviruses

AbstractIn addition to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), humans are also susceptible to six other coronaviruses, for which consecutive exposures to antigenically related and divergent seasonal coronaviruses are frequent. Despite the prevalence of COVID-19 pandemic and ongoing research, the nature of the antibody response against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is unclear. Here we longitudinally profile the early humoral immune response against SARS-CoV-2 in hospitalized coronavirus disease 2019 (COVID-19) patients and quantify levels of pre-existing immunity to OC43, HKU1 and 229E seasonal coronaviruses, and find a strong back-boosting effect to conserved but not variable regions of OC43 and HKU1 betacoronaviruses spike protein. However, such antibody memory boost to human coronaviruses negatively correlates with the induction of IgG and IgM against SARS-CoV-2 spike and nucleocapsid protein. Our findings thus provide evidence of immunological imprinting by previous seasonal coronavirus infections that can potentially modulate the antibody profile to SARS-CoV-2 infection.

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Serological profiles of pan-coronavirus-specific responses in COVID-19 patients using a multiplexed electro-chemiluminescence-based testing platform

10.1101/2021.03.23.21253460 ◽

2021 ◽

Author(s):

Sidhartha Chaudhury ◽

Jack Hutter ◽

Jessica S Bolton ◽

Shilpa Hakre ◽

Evelyn Mose ◽

...

Keyword(s):

Nucleocapsid Protein ◽

Cross Reactivity ◽

Multiplex Assay ◽

Spike Protein ◽

Contact Tracing ◽

Epitope Specificity ◽

Army Hospital ◽

Protein Receptor ◽

Healthcare Administrators ◽

Human Coronaviruses

AbstractSerological assessment of SARS-CoV-2 specific responses are an essential tool for determining the prevalence of past SARS-CoV-2 infections in the population especially when testing occurs after symptoms have developed and limited contact tracing is in place. The goal of our study was to test a new 10-plex electro-chemiluminescence-based assay to measure IgM and IgG responses to the spike proteins from multiple human coronaviruses including SARS-CoV-2, assess the epitope specificity of the SARS-CoV-2 antibody response against full-length spike protein, receptor-binding domain and N-terminal domain of the spike protein, and the nucleocapsid protein. We carried out the assay on samples collected from three sample groups: subjects diagnosed with COVID-19 from the U.S. Army hospital at Camp Humphreys in Pyeongtaek, South Korea; healthcare administrators from the same hospital but with no reported diagnosis of COVID-19; and pre-pandemic samples. We found that the new CoV-specific multiplex assay was highly sensitive allowing plasma samples to be diluted 1:30,000 with a robust signal. The reactivity of IgG responses to SARS-CoV-2 nucleocapsid protein and IgM responses to SARS-CoV-2 spike protein could distinguish COVID-19 samples from non-COVID-19 and pre-pandemic samples. The data from the three sample groups also revealed a unique pattern of cross-reactivity between SARS-CoV-2 and SARS-CoV-1, MERS-CoV, and seasonal coronaviruses HKU1 and OC43. Our findings show that the CoV-2 IgM response is highly specific while the CoV-2 IgG response is more cross-reactive across a range of human CoVs and also showed that IgM and IgG responses show distinct patterns of epitope specificity. In summary, this multiplex assay was able to distinguish samples by COVID-19 status and characterize distinct trends in terms of cross-reactivity and fine-specificity in antibody responses, underscoring its potential value in diagnostic or serosurveillance efforts.

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Phylogenomics and population genomics of SARS-CoV-2 in Mexico reveals variants of interest (VOI) and a mutation in the Nucleocapsid protein associated with symptomatic versus asymptomatic carriers

10.1101/2021.05.18.21256128 ◽

2021 ◽

Author(s):

Francisco Barona-Gomez ◽

Luis Delaye ◽

Erik Diaz-Valenzuela ◽

Fabien Plisson ◽

Arely Cruz-Perez ◽

...

Keyword(s):

Nucleocapsid Protein ◽

Population Genomics ◽

Bimodal Distribution ◽

Central Mexico ◽

Binding Motif ◽

Single Nucleotide Variants ◽

Nucleocapsid Proteins ◽

Asymptomatic Carriers ◽

Genetic Patterns

Understanding the evolution of SARS-CoV-2 virus in various regions of the world during the Covid19 pandemic is of the utmost importance to help mitigate the effects of this devastating disease. We describe the phylogenomic and population genetic patterns of the virus in Mexico during the pre-vaccination stage, including asymptomatic carriers. Our RT-qPCR screening and phylogenomics directed a sequence/structure analysis of the Spike glycoprotein, revealing mutation of concern E484K in genomes from central Mexico, in addition to the nationwide prevalence of the imported variant 20C/S:452R (B.1.427/9). Overall, the detected variants in Mexico show mutations in the N-terminal domain (i.e., R190M), in the receptor-binding motif (i.e., T478K, E484K), within the S1-S2 subdomains (i.e., P681R/H, T732A), and at the basis of the protein, V1176F, raising concerns about the lack of phenotypic and clinical data available for the postulated variants of interest (VOIs) 20B/478K.V1 and P.3. Moreover, the population patterns of Single Nucleotide Variants (SNVs) from symptomatic and asymptomatic carriers sampled with a self-sampling scheme, revealed a bimodal distribution of polymorphisms in all three sampled localities from central Mexico, and confirmed the presence of several fixed variants, mostly from the 241T-3037T-14408T-23403G haplotype common in Asia. Despite gene flow among Mexican localities, we found differences in both the allelic frequencies among localities and the allelic imbalance of the mutation S194L of the nucleocapsid protein between symptomatic and asymptomatic carriers. Our results highlight the dual role of Spike and Nucleocapsid proteins in adaptive evolution of SARS-CoV-2 to their hosts and provide a baseline for specific follow-up of mutations of concern during the vaccination stage in Mexico.

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M-X-I Motif of Semliki Forest Virus Capsid Protein Affects Nucleocapsid Assembly

Journal of Virology ◽

10.1128/jvi.75.10.4625-4632.2001 ◽

2001 ◽

Vol 75 (10) ◽

pp. 4625-4632 ◽

Cited By ~ 17

Author(s):

Ulrica Skoging-Nyberg ◽

Peter Liljeström

Keyword(s):

Plasma Membrane ◽

Capsid Protein ◽

Semliki Forest Virus ◽

Spike Protein ◽

Spherical Particles ◽

Binding Motif ◽

Wild Type ◽

Nucleocapsid Proteins ◽

Binding Cavity ◽

Virus Capsid Protein

ABSTRACT Alphavirus budding is driven by interactions between spike and nucleocapsid proteins at the plasma membrane. The binding motif, Y-X-L, on the spike protein E2 and the corresponding hydrophobic cavity on the capsid protein were described earlier. The spike-binding cavity has also been suggested to bind an internal hydrophobic motif, M113-X-I115, of the capsid protein. In this study we found that replacement of amino acids M113 and I115 with alanines, as single or double mutations, abolished formation of intracellular nucleocapsids. The mutants could still bud efficiently, but the NCs in the released virions were not stable after removal of the membrane and spike protein layer. In addition to wild-type spherical particles, elongated multicored particles were found at the plasma membrane and released from the host cell. We conclude that the internal capsid motif has a biological function in the viral life cycle, especially in assembly of nucleocapsids. We also provide further evidence that alphaviruses may assemble and bud from the plasma membrane in the absence of preformed nucleocapsids.

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A COVID-19 antibody curbs SARS-CoV-2 nucleocapsid protein-induced complement hyper-activation

10.1101/2020.09.10.292318 ◽

2020 ◽

Author(s):

Sisi Kang ◽

Mei Yang ◽

Suhua He ◽

Yueming Wang ◽

Xiaoxue Chen ◽

...

Keyword(s):

Nucleocapsid Protein ◽

Distress Syndrome ◽

Rna Binding ◽

Complex Structure ◽

Antibody Responses ◽

Spike Protein ◽

Structural Determination ◽

N Protein ◽

Human Antibodies ◽

Quick Recovery

AbstractAlthough human antibodies elicited by severe acute respiratory distress syndrome coronavirus-2 (SARS-CoV-2) nucleocapsid (N) protein are profoundly boosted upon infection, little is known about the function of N-directed antibodies. Herein, we isolated and profiled a panel of 32 N protein-specific monoclonal antibodies (mAb) from a quick recovery coronavirus disease-19 (COVID-19) convalescent, who had dominant antibody responses to SARS-CoV-2 N protein rather than to Spike protein. The complex structure of N protein RNA binding domain with the highest binding affinity mAb nCoV396 reveals the epitopes and antigen’s allosteric changes. Functionally, a virus-free complement hyper-activation analysis demonstrates that nCoV396 specifically compromises N protein-induced complement hyper-activation, a risk factor for morbidity and mortality in COVID-19, thus paving the way for functional anti-N mAbs identification.One Sentence SummaryB cell profiling, structural determination, and protease activity assays identify a functional antibody to N protein.

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Serological profiles of pan-coronavirus-specific responses in COVID-19 patients using a multiplexed electro-chemiluminescence-based testing platform

PLoS ONE ◽

10.1371/journal.pone.0252628 ◽

2021 ◽

Vol 16 (6) ◽

pp. e0252628

Author(s):

Sidhartha Chaudhury ◽

Jack Hutter ◽

Jessica S. Bolton ◽

Shilpa Hakre ◽

Evelyn Mose ◽

...

Keyword(s):

Nucleocapsid Protein ◽

Cross Reactivity ◽

Multiplex Assay ◽

Spike Protein ◽

Contact Tracing ◽

Epitope Specificity ◽

Army Hospital ◽

Protein Receptor ◽

Healthcare Administrators ◽

Human Coronaviruses

Serological assessment of SARS-CoV-2 specific responses are an essential tool for determining the prevalence of past SARS-CoV-2 infections in the population especially when testing occurs after symptoms have developed and limited contact tracing is in place. The goal of our study was to test a new 10-plex electro-chemiluminescence-based assay to measure IgM and IgG responses to the spike proteins from multiple human coronaviruses including SARS-CoV-2, assess the epitope specificity of the SARS-CoV-2 antibody response against full-length spike protein, receptor-binding domain and N-terminal domain of the spike protein, and the nucleocapsid protein. We carried out the assay on samples collected from three sample groups: subjects diagnosed with COVID-19 from the U.S. Army hospital at Camp Humphreys in Pyeongtaek, South Korea; healthcare administrators from the same hospital but with no reported diagnosis of COVID-19; and pre-pandemic samples. We found that the new CoV-specific multiplex assay was highly sensitive allowing plasma samples to be diluted 1:30,000 with a robust signal. The reactivity of IgG responses to SARS-CoV-2 nucleocapsid protein and IgM responses to SARS-CoV-2 spike protein could distinguish COVID-19 samples from non-COVID-19 and pre-pandemic samples. The data from the three sample groups also revealed a unique pattern of cross-reactivity between SARS-CoV-2 and SARS-CoV-1, MERS-CoV, and seasonal coronaviruses HKU1 and OC43. Our findings show that the CoV-2 IgM response is highly specific while the CoV-2 IgG response is more cross-reactive across a range of human CoVs and also showed that IgM and IgG responses show distinct patterns of epitope specificity. In summary, this multiplex assay was able to distinguish samples by COVID-19 status and characterize distinct trends in terms of cross-reactivity and fine-specificity in antibody responses, underscoring its potential value in diagnostic or serosurveillance efforts.

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The Combined Human Genotype of Truncating TTN and RBM20 Mutations Is Associated with Severe and Early Onset of Dilated Cardiomyopathy

Genes ◽

10.3390/genes12060883 ◽

2021 ◽

Vol 12 (6) ◽

pp. 883

Author(s):

Anna Gaertner ◽

Julia Bloebaum ◽

Andreas Brodehl ◽

Baerbel Klauke ◽

Katharina Sielemann ◽

...

Keyword(s):

Heart Failure ◽

Dilated Cardiomyopathy ◽

Early Onset ◽

Target Genes ◽

Frameshift Mutation ◽

Rna Binding ◽

Splicing Factor ◽

Binding Motif ◽

Rich Domain ◽

Generation Sequencing

A major cause of heart failure is cardiomyopathies, with dilated cardiomyopathy (DCM) as the most common form. Over 40 genes are linked to DCM, among them TTN and RBM20. Next Generation Sequencing in clinical DCM cohorts revealed truncating variants in TTN (TTNtv), accounting for up to 25% of familial DCM cases. Mutations in the cardiac splicing factor RNA binding motif protein 20 (RBM20) are also known to be associated with severe cardiomyopathies. TTN is one of the major RBM20 splicing targets. Most of the pathogenic RBM20 mutations are localized in the highly conserved arginine serine rich domain (RS), leading to a cytoplasmic mislocalization of mutant RBM20. Here, we present a patient with an early onset DCM carrying a combination of (likely) pathogenic TTN and RBM20 mutations. We show that the splicing of RBM20 target genes is affected in the mutation carrier. Furthermore, we reveal RBM20 haploinsufficiency presumably caused by the frameshift mutation in RBM20.

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Immunization with RBD-P2 and N protects against SARS-CoV-2 in nonhuman primates

Science Advances ◽

10.1126/sciadv.abg7156 ◽

2021 ◽

Vol 7 (22) ◽

pp. eabg7156

Author(s):

So-Hee Hong ◽

Hanseul Oh ◽

Yong Wook Park ◽

Hye Won Kwak ◽

Eun Young Oh ◽

...

Keyword(s):

Nucleocapsid Protein ◽

Nonhuman Primates ◽

Vaccine Candidate ◽

Statistical Significance ◽

Neutralizing Antibody ◽

Spike Protein ◽

Vaccine Candidates ◽

Cell Responses ◽

Antibody Levels ◽

Further Development

Since the emergence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), various vaccines are being developed, with most vaccine candidates focusing on the viral spike protein. Here, we developed a previously unknown subunit vaccine comprising the receptor binding domain (RBD) of the spike protein fused with the tetanus toxoid epitope P2 (RBD-P2) and tested its efficacy in rodents and nonhuman primates (NHPs). We also investigated whether the SARS-CoV-2 nucleocapsid protein (N) could increase vaccine efficacy. Immunization with N and RBD-P2 (RBDP2/N) + alum increased T cell responses in mice and neutralizing antibody levels in rats compared with those obtained using RBD-P2 + alum. Furthermore, in NHPs, RBD-P2/N + alum induced slightly faster SARS-CoV-2 clearance than that induced by RBD-P2 + alum, albeit without statistical significance. Our study supports further development of RBD-P2 as a vaccine candidate against SARS-CoV-2. Also, it provides insights regarding the use of N in protein-based vaccines against SARS-CoV-2.

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Design of a companion bioinformatic tool to detect the emergence and geographical distribution of SARS-CoV-2 Spike protein genetic variants

Journal of Translational Medicine ◽

10.1186/s12967-020-02675-4 ◽

2020 ◽

Vol 18 (1) ◽

Author(s):

Alice Massacci ◽

Eleonora Sperandio ◽

Lorenzo D’Ambrosio ◽

Mariano Maffei ◽

Fabio Palombo ◽

...

Keyword(s):

Receptor Binding ◽

Consensus Sequence ◽

Cell Epitope ◽

Vaccine Design ◽

Binding Domain ◽

Spike Protein ◽

Antibody Activity ◽

Binding Motif ◽

Receptor Binding Domain ◽

The Impact

Abstract Background Tracking the genetic variability of Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2) is a crucial challenge. Mainly to identify target sequences in order to generate robust vaccines and neutralizing monoclonal antibodies, but also to track viral genetic temporal and geographic evolution and to mine for variants associated with reduced or increased disease severity. Several online tools and bioinformatic phylogenetic analyses have been released, but the main interest lies in the Spike protein, which is the pivotal element of current vaccine design, and in the Receptor Binding Domain, that accounts for most of the neutralizing the antibody activity. Methods Here, we present an open-source bioinformatic protocol, and a web portal focused on SARS-CoV-2 single mutations and minimal consensus sequence building as a companion vaccine design tool. Furthermore, we provide immunogenomic analyses to understand the impact of the most frequent RBD variations. Results Results on the whole GISAID sequence dataset at the time of the writing (October 2020) reveals an emerging mutation, S477N, located on the central part of the Spike protein Receptor Binding Domain, the Receptor Binding Motif. Immunogenomic analyses revealed some variation in mutated epitope MHC compatibility, T-cell recognition, and B-cell epitope probability for most frequent human HLAs. Conclusions This work provides a framework able to track down SARS-CoV-2 genomic variability.

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