Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 15 de 15
Filter
1.
Front Immunol ; 12: 767347, 2021.
Article in English | MEDLINE | ID: covidwho-1528823

ABSTRACT

Infection with SARS-CoV-2 triggers the simultaneous activation of innate inflammatory pathways including the complement system and the kallikrein-kinin system (KKS) generating in the process potent vasoactive peptides that contribute to severe acute respiratory syndrome (SARS) and multi-organ failure. The genome of SARS-CoV-2 encodes four major structural proteins - the spike (S) protein, nucleocapsid (N) protein, membrane (M) protein, and the envelope (E) protein. However, the role of these proteins in either binding to or activation of the complement system and/or the KKS is still incompletely understood. In these studies, we used: solid phase ELISA, hemolytic assay and surface plasmon resonance (SPR) techniques to examine if recombinant proteins corresponding to S1, N, M and E: (a) bind to C1q, gC1qR, FXII and high molecular weight kininogen (HK), and (b) activate complement and/or the KKS. Our data show that the viral proteins: (a) bind C1q and activate the classical pathway of complement, (b) bind FXII and HK, and activate the KKS in normal human plasma to generate bradykinin and (c) bind to gC1qR, the receptor for the globular heads of C1q (gC1q) which in turn could serve as a platform for the activation of both the complement system and KKS. Collectively, our data indicate that the SARS-CoV-2 viral particle can independently activate major innate inflammatory pathways for maximal damage and efficiency. Therefore, if efficient therapeutic modalities for the treatment of COVID-19 are to be designed, a strategy that includes blockade of the four major structural proteins may provide the best option.


Subject(s)
Antigens, Viral/immunology , COVID-19/immunology , Complement System Proteins/immunology , Kallikrein-Kinin System , SARS-CoV-2/immunology , Viral Structural Proteins/immunology , Carrier Proteins/genetics , Carrier Proteins/immunology , Hemolysis , Humans , Mitochondrial Proteins/genetics , Mitochondrial Proteins/immunology , Recombinant Proteins/immunology , Viral Structural Proteins/genetics
2.
PLoS One ; 16(11): e0258645, 2021.
Article in English | MEDLINE | ID: covidwho-1518355

ABSTRACT

All approved coronavirus disease 2019 (COVID-19) vaccines in current use are safe, effective, and reduce the risk of severe illness. Although data on the immunological presentation of patients with COVID-19 is limited, increasing experimental evidence supports the significant contribution of B and T cells towards the resolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Despite the availability of several COVID-19 vaccines with high efficacy, more effective vaccines are still needed to protect against the new variants of SARS-CoV-2. Employing a comprehensive immunoinformatic prediction algorithm and leveraging the genetic closeness with SARS-CoV, we have predicted potential immune epitopes in the structural proteins of SARS-CoV-2. The S and N proteins of SARS-CoV-2 and SARS-CoVs are main targets of antibody detection and have motivated us to design four multi-epitope vaccines which were based on our predicted B- and T-cell epitopes of SARS-CoV-2 structural proteins. The cardinal epitopes selected for the vaccine constructs are predicted to possess antigenic, non-allergenic, and cytokine-inducing properties. Additionally, some of the predicted epitopes have been experimentally validated in published papers. Furthermore, we used the C-ImmSim server to predict effective immune responses induced by the epitope-based vaccines. Taken together, the immune epitopes predicted in this study provide a platform for future experimental validations which may facilitate the development of effective vaccine candidates and epitope-based serological diagnostic assays.


Subject(s)
Computational Biology , Epitope Mapping , SARS-CoV-2/immunology , Viral Structural Proteins/immunology , Amino Acid Sequence , COVID-19 Vaccines/chemistry , COVID-19 Vaccines/immunology , Databases as Topic , Epitopes, B-Lymphocyte/chemistry , Epitopes, B-Lymphocyte/immunology , Epitopes, T-Lymphocyte/chemistry , Epitopes, T-Lymphocyte/immunology , Histocompatibility Antigens Class I/metabolism , Humans , Models, Molecular , Protein Conformation , Reproducibility of Results , Viral Structural Proteins/chemistry
3.
Front Immunol ; 12: 724763, 2021.
Article in English | MEDLINE | ID: covidwho-1399141

ABSTRACT

Characterizing the serologic features of asymptomatic SARS-CoV-2 infection is imperative to improve diagnostics and control of SARS-CoV-2 transmission. In this study, we evaluated the antibody profiles in 272 plasma samples collected from 59 COVID-19 patients, consisting of 18 asymptomatic patients, 33 mildly ill patients and 8 severely ill patients. We measured the IgG against five viral structural proteins, different isotypes of immunoglobulins against the Receptor Binding Domain (RBD) protein, and neutralizing antibodies. The results showed that the overall antibody response was lower in asymptomatic infections than in symptomatic infections throughout the disease course. In contrast to symptomatic patients, asymptomatic patients showed a dominant IgG-response towards the RBD protein, but not IgM and IgA. Neutralizing antibody titers had linear correlations with IgA/IgM/IgG levels against SARS-CoV-2-RBD, as well as with IgG levels against multiple SARS-CoV-2 structural proteins, especially with anti-RBD or anti-S2 IgG. In addition, the sensitivity of anti-S2-IgG is better in identifying asymptomatic infections at early time post infection compared to anti-RBD-IgG. These data suggest that asymptomatic infections elicit weaker antibody responses, and primarily induce IgG antibody responses rather than IgA or IgM antibody responses. Detection of IgG against the S2 protein could supplement nucleic acid testing to identify asymptomatic patients. This study provides an antibody detection scheme for asymptomatic infections, which may contribute to epidemic prevention and control.


Subject(s)
Antibodies, Viral/blood , Asymptomatic Infections , Immunoglobulin G/blood , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Viral Structural Proteins/immunology , Adolescent , Adult , Antibodies, Neutralizing/immunology , Antibodies, Viral/physiology , Binding Sites, Antibody , Female , Humans , Immunoglobulin G/classification , Immunoglobulin M/immunology , Kinetics , Male , Middle Aged , Neutralization Tests/statistics & numerical data , SARS-CoV-2/chemistry , Young Adult
5.
PLoS One ; 16(8): e0254605, 2021.
Article in English | MEDLINE | ID: covidwho-1367703

ABSTRACT

The re-emergence of virulent strains of the Infectious Bursal Disease Virus (IBDV) leads to significant economic losses of poultry industry in Pakistan during last few years. This disease causes the infection of bursa, which leads to major immune losses. A total number of 30 samples from five IBD outbreaks during the period of 2019-20 were collected from different areas of Faisalabad district, Pakistan and assayed by targeting the IBD virus VP2 region through RT-PCR. Among all the outbreaks, almost 80% of poultry birds were found positive for the IBDV. The bursa tissues were collected from the infected birds and histopathological examination of samples revealed severe lymphocytic depletion, infiltration of inflammatory cells, and necrosis of the bursa of Fabricius (BF). Positive samples were subjected to re-isolation and molecular characterization of IBDV. The Pakistan IBDV genes were subjected to DNA sequencing to determine the virus nucleotide sequences. The sequences of 100 Serotype-I IBDVs showing nearest homology were compared and identified with the study sequence. The construction of the phylogenetic tree for nucleotide sequences was accomplished by the neighbor-joining method in MEGA-6 with reference strains. The VP2 segment reassortment of IBDVs carrying segment A were identified as one important type of circulating strains in Pakistan. The findings indicated the molecular features of the Pakistan IBDV strains playing a role in the evolution of new strains of the virus, which will contribute to the vaccine selection and effective prevention of the disease.


Subject(s)
Birnaviridae Infections/epidemiology , Infectious bursal disease virus/pathogenicity , Poultry/virology , Vaccines/pharmacology , Animals , Birnaviridae Infections/veterinary , Birnaviridae Infections/virology , Bursa of Fabricius/pathology , Bursa of Fabricius/virology , Chickens/virology , Disease Outbreaks/veterinary , Humans , Infectious bursal disease virus/genetics , Pakistan/epidemiology , Phylogeny , Poultry Diseases/virology , Viral Structural Proteins/genetics , Viral Structural Proteins/immunology
6.
Front Immunol ; 12: 688436, 2021.
Article in English | MEDLINE | ID: covidwho-1259348

ABSTRACT

Background: Adaptive immune responses to structural proteins of the virion play a crucial role in protection against coronavirus disease 2019 (COVID-19). We therefore studied T cell responses against multiple SARS-CoV-2 structural proteins in a large cohort using a simple, fast, and high-throughput approach. Methods: An automated interferon gamma release assay (IGRA) for the Nucleocapsid (NC)-, Membrane (M)-, Spike-C-terminus (SCT)-, and N-terminus-protein (SNT)-specific T cell responses was performed using fresh whole blood from study subjects with convalescent, confirmed COVID-19 (n = 177, more than 200 days post infection), exposed household members (n = 145), and unexposed controls (n = 85). SARS-CoV-2-specific antibodies were assessed using Elecsys® Anti-SARS-CoV-2 (Ro-N-Ig) and Anti-SARS-CoV-2-ELISA (IgG) (EI-S1-IgG). Results: 156 of 177 (88%) previously PCR confirmed cases were still positive by Ro-N-Ig more than 200 days after infection. In T cells, most frequently the M-protein was targeted by 88% seropositive, PCR confirmed cases, followed by SCT (85%), NC (82%), and SNT (73%), whereas each of these antigens was recognized by less than 14% of non-exposed control subjects. Broad targeting of these structural virion proteins was characteristic of convalescent SARS-CoV-2 infection; 68% of all seropositive individuals targeted all four tested antigens. Indeed, anti-NC antibody titer correlated loosely, but significantly with the magnitude and breadth of the SARS-CoV-2-specific T cell response. Age, sex, and body mass index were comparable between the different groups. Conclusion: SARS-CoV-2 seropositivity correlates with broad T cell reactivity of the structural virus proteins at 200 days after infection and beyond. The SARS-CoV-2-IGRA can facilitate large scale determination of SARS-CoV-2-specific T cell responses with high accuracy against multiple targets.


Subject(s)
COVID-19/immunology , Interferon-gamma/immunology , SARS-CoV-2/immunology , T-Lymphocytes/immunology , Viral Structural Proteins/immunology , Adolescent , Adult , Aged , Aged, 80 and over , Antibodies, Viral/blood , COVID-19/blood , Female , Humans , Interferon-gamma Release Tests , Male , Middle Aged , Young Adult
7.
Clin Microbiol Infect ; 27(6): 916.e1-916.e4, 2021 Jun.
Article in English | MEDLINE | ID: covidwho-1155451

ABSTRACT

OBJECTIVE: T-cell responses against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are observed in unexposed individuals. We evaluated the impact of this pre-existing cellular response on incident SARS-CoV-2 infections. METHODS: This was a follow-up study of 38 seronegative healthcare workers (HCWs) with previous evaluation of CD8+ and CD4+ T-cell responses after stimulation with SARS-CoV-2 structural proteins. Infection was considered in the presence of a positive RT-PCR test and/or confirmed seroconversion. RESULTS: Twenty of the 38 HCWs included (53%) had a previous specific CD8+ T-cell response to peptides encompassing the spike protein (S) in 13 (34%), the membrane (M) in 17 (45%), or/and the nucleocapsid (N) in three (8%). During a follow-up of 189 days (interquartile range (IQR) 172-195), 11 HCWs (29%) had an RT-PCR-positive test (n = 9) or seroconverted (n = 2). Median duration of symptoms was 2 days (IQR 0-7), and time to negative RT-PCR was 9 days (IQR 4-10). Notably, six incident infections (55%) occurred in HCWs with a pre-existing T-cell response (30% of those with a cellular response), who showed a significantly lower duration of symptoms (three were asymptomatic). Three of the six HCWs having a previous T-cell response continued to test seronegative. All the infected patients developed a robust T-cell response to different structural SARS-CoV-2 proteins, especially to protein S (91%). CONCLUSION: A pre-existing T-cell response does not seem to reduce incident SARS-CoV-2 infections, but it may contribute to asymptomatic or mild disease, rapid viral clearance and differences in seroconversion.


Subject(s)
COVID-19/immunology , T-Lymphocytes/immunology , Viral Structural Proteins/immunology , Adult , Antibodies, Viral , COVID-19 Nucleic Acid Testing , Female , Follow-Up Studies , Health Personnel , Humans , Immunity , Male , Middle Aged , Prospective Studies , Seroconversion , Young Adult
8.
Int J Mol Sci ; 22(5)2021 Mar 05.
Article in English | MEDLINE | ID: covidwho-1129735

ABSTRACT

We observed substantial differences in predicted Major Histocompatibility Complex II (MHCII) epitope presentation of SARS-CoV-2 proteins for different populations but only minor differences in predicted MHCI epitope presentation. A comparison of this predicted epitope MHC-coverage revealed for the early phase of infection spread (till day 15 after reaching 128 observed infection cases) highly significant negative correlations with the case fatality rate. Specifically, this was observed in different populations for MHC class II presentation of the viral spike protein (p-value: 0.0733 for linear regression), the envelope protein (p-value: 0.023), and the membrane protein (p-value: 0.00053), indicating that the high case fatality rates of COVID-19 observed in some countries seem to be related with poor MHC class II presentation and hence weak adaptive immune response against these viral envelope proteins. Our results highlight the general importance of the SARS-CoV-2 structural proteins in immunological control in early infection spread looking at a global census in various countries and taking case fatality rate into account. Other factors such as health system and control measures become more important after the early spread. Our study should encourage further studies on MHCII alleles as potential risk factors in COVID-19 including assessment of local populations and specific allele distributions.


Subject(s)
COVID-19/mortality , Histocompatibility Antigens Class II/genetics , Histocompatibility Antigens Class II/immunology , SARS-CoV-2/chemistry , Viral Structural Proteins/chemistry , Adaptive Immunity , Alleles , COVID-19/immunology , COVID-19/transmission , Computational Biology/methods , Correlation of Data , Epitopes, B-Lymphocyte/genetics , Epitopes, B-Lymphocyte/immunology , Epitopes, T-Lymphocyte/genetics , Epitopes, T-Lymphocyte/immunology , HLA Antigens/genetics , Histocompatibility Antigens Class I/genetics , Histocompatibility Antigens Class I/immunology , Humans , Mortality , SARS-CoV-2/immunology , Viral Structural Proteins/immunology
9.
J Clin Microbiol ; 59(2)2021 01 21.
Article in English | MEDLINE | ID: covidwho-1041778

ABSTRACT

Reliable serological tests are required to determine the prevalence of antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and to characterize immunity to the disease in order to address key knowledge gaps in the coronavirus disease 2019 (COVID-19) pandemic. Quantitative suspension array technology (qSAT) assays based on the xMAP Luminex platform overcome the limitations of rapid diagnostic tests and enzyme-linked immunosorbent assays (ELISAs) with their higher precision, dynamic range, throughput, miniaturization, cost-efficiency, and multiplexing capacity. We developed three qSAT assays for IgM, IgA, and IgG against a panel of eight SARS-CoV-2 antigens, including spike protein (S), nucleocapsid protein (N), and membrane protein (M) constructs. The assays were optimized to minimize the processing time and maximize the signal-to-noise ratio. We evaluated their performances using 128 prepandemic plasma samples (negative controls) and 104 plasma samples from individuals with SARS-CoV-2 diagnosis (positive controls), of whom 5 were asymptomatic, 51 had mild symptoms, and 48 were hospitalized. Preexisting IgG antibodies recognizing N, M, and S proteins were detected in negative controls, which is suggestive of cross-reactivity to common-cold coronaviruses. The best-performing antibody/antigen signatures had specificities of 100% and sensitivities of 95.78% at ≥14 days and 95.65% at ≥21 days since the onset of symptoms, with areas under the curve (AUCs) of 0.977 and 0.999, respectively. Combining multiple markers as assessed by qSAT assays has the highest efficiency, breadth, and versatility to accurately detect low-level antibody responses for obtaining reliable data on the prevalence of exposure to novel pathogens in a population. Our assays will allow gaining insights into antibody correlates of immunity and their kinetics, required for vaccine development to combat the COVID-19 pandemic.


Subject(s)
Antigens, Viral/immunology , COVID-19 Serological Testing/methods , COVID-19/diagnosis , Immunoglobulin Isotypes/blood , SARS-CoV-2/immunology , Adult , Antibodies, Viral/blood , COVID-19/blood , Cross Reactions , Female , Humans , Immunoassay , Male , Middle Aged , Reproducibility of Results , Sensitivity and Specificity , Viral Structural Proteins/immunology
10.
Theranostics ; 11(4): 1690-1702, 2021.
Article in English | MEDLINE | ID: covidwho-1013521

ABSTRACT

The global outbreak of a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) highlighted a requirement for two pronged clinical interventions such as development of effective vaccines and acute therapeutic options for medium-to-severe stages of "coronavirus disease 2019" (COVID-19). Effective vaccines, if successfully developed, have been emphasized to become the most effective strategy in the global fight against the COVID-19 pandemic. Basic research advances in biotechnology and genetic engineering have already provided excellent progress and groundbreaking new discoveries in the field of the coronavirus biology and its epidemiology. In particular, for the vaccine development the advances in characterization of a capsid structure and identification of its antigens that can become targets for new vaccines. The development of the experimental vaccines requires a plethora of molecular techniques as well as strict compliance with safety procedures. The research and clinical data integrity, cross-validation of the results, and appropriated studies from the perspective of efficacy and potently side effects have recently become a hotly discussed topic. In this review, we present an update on latest advances and progress in an ongoing race to develop 52 different vaccines against SARS-CoV-2. Our analysis is focused on registered clinical trials (current as of November 04, 2020) that fulfill the international safety and efficacy criteria in the vaccine development. The requirements as well as benefits and risks of diverse types of SARS-CoV-2 vaccines are discussed including those containing whole-virus and live-attenuated vaccines, subunit vaccines, mRNA vaccines, DNA vaccines, live vector vaccines, and also plant-based vaccine formulation containing coronavirus-like particle (VLP). The challenges associated with the vaccine development as well as its distribution, safety and long-term effectiveness have also been highlighted and discussed.


Subject(s)
COVID-19 Vaccines , COVID-19/epidemiology , Drug Development/trends , Pandemics/prevention & control , SARS-CoV-2/immunology , Antigens, Viral/genetics , Antigens, Viral/immunology , COVID-19/prevention & control , COVID-19/transmission , COVID-19/virology , Clinical Trials as Topic/statistics & numerical data , Drug Approval , Drug Development/statistics & numerical data , Humans , Patient Safety , SARS-CoV-2/genetics , Time Factors , Treatment Outcome , Viral Structural Proteins/genetics , Viral Structural Proteins/immunology
11.
Emerg Microbes Infect ; 9(1): 2653-2662, 2020 Dec.
Article in English | MEDLINE | ID: covidwho-977352

ABSTRACT

In the face of COVID-19 pandemic caused by the newly emerged SARS-CoV-2, an inactivated, Vero cell-based, whole virion vaccine candidate has been developed and entered into phase III clinical trials within six months. Biochemical and immunogenic characterization of structural proteins and their post-translational modifications in virions, the end-products of the vaccine candidate, would be essential for the quality control and process development of vaccine products and for studying the immunogenicity and pathogenesis of SARS-CoV-2. By using a panel of rabbit antisera against virions and five structural proteins together with a convalescent serum, the spike (S) glycoprotein was shown to be N-linked glycosylated, PNGase F-sensitive, endoglycosidase H-resistant and cleaved by Furin-like proteases into S1 and S2 subunits. The full-length S and S1/S2 subunits could form homodimers/trimers. The membrane (M) protein was partially N-linked glycosylated; the accessory protein 3a existed in three different forms, indicative of cleavage and dimerization. Furthermore, analysis of the antigenicity of these proteins and their post-translationally modified forms demonstrated that S protein induced the strongest antibody response in both convalescent and immunized animal sera. Interestingly, immunization with the inactivated vaccine did not elicit antibody response against the S2 subunit, whereas strong antibody response against both S1 and S2 subunits was detected in the convalescent serum. Moreover, vaccination stimulated stronger antibody response against S multimers than did the natural infection. This study revealed that the native S glycoprotein stimulated neutralizing antibodies, while bacterially-expressed S fragments did not. The study on S modifications would facilitate design of S-based anti-SARS-CoV-2 vaccines.


Subject(s)
COVID-19 Vaccines , Protein Processing, Post-Translational , SARS-CoV-2/isolation & purification , Viral Structural Proteins , Virion , Animals , Antigens, Viral/analysis , Antigens, Viral/metabolism , COVID-19 Vaccines/chemistry , COVID-19 Vaccines/immunology , Cattle , Chlorocebus aethiops , Humans , Rabbits , SARS-CoV-2/immunology , Vaccines, Inactivated/chemistry , Vaccines, Inactivated/immunology , Vero Cells , Viral Structural Proteins/chemistry , Viral Structural Proteins/immunology , Viral Structural Proteins/isolation & purification , Virion/chemistry , Virion/immunology , Virion/isolation & purification
12.
Sci Rep ; 10(1): 20864, 2020 11 30.
Article in English | MEDLINE | ID: covidwho-951878

ABSTRACT

Coronavirus disease 2019 (COVID-19) is an acute pneumonic disease, with no prophylactic or specific therapeutical solution. Effective and rapid countermeasure against the spread of the disease's associated virus, SARS-CoV-2, requires to incorporate the computational approach. In this study, we employed various immunoinformatics tools to design a multi-epitope vaccine polypeptide with the highest potential for activating the human immune system against SARS-CoV-2. The initial epitope set was extracted from the whole set of viral structural proteins. Potential non-toxic and non-allergenic T-cell and B-cell binding and cytokine inducing epitopes were then identified through a priori prediction. Selected epitopes were bound to each other with appropriate linkers, followed by appending a suitable adjuvant to increase the immunogenicity of the vaccine polypeptide. Molecular modelling of the 3D structure of the vaccine construct, docking, molecular dynamics simulations and free energy calculations confirmed that the vaccine peptide had high affinity for Toll-like receptor 3 binding, and that the vaccine-receptor complex was highly stable. As our vaccine polypeptide design captures the advantages of structural epitopes and simultaneously integrates precautions to avoid relevant side effects, it is suggested to be promising for elicitation of an effective and safe immune response against SARS-CoV-2 in vivo.


Subject(s)
COVID-19 Vaccines/immunology , COVID-19/prevention & control , SARS-CoV-2/immunology , Vaccines, Subunit/immunology , Viral Structural Proteins/immunology , Computational Biology , Epitopes, B-Lymphocyte/immunology , Epitopes, T-Lymphocyte/immunology , Humans , Immunogenicity, Vaccine , Models, Molecular , Molecular Docking Simulation , Molecular Dynamics Simulation , Toll-Like Receptor 3/metabolism
13.
Sci Rep ; 10(1): 18995, 2020 11 04.
Article in English | MEDLINE | ID: covidwho-910353

ABSTRACT

The current pandemic is caused by the SARS-CoV-2 virus and large progress in understanding the pathology of the virus has been made since its emergence in late 2019. Several reports indicate short lasting immunity against endemic coronaviruses, which contrasts studies showing that biobanked venous blood contains T cells reactive to SARS-CoV-2 S-protein even before the outbreak in Wuhan. This suggests a preformed T cell memory towards structural proteins in individuals not exposed to SARS-CoV-2. Given the similarity of SARS-CoV-2 to other members of the Coronaviridae family, the endemic coronaviruses appear likely candidates to generate this T cell memory. However, given the apparent poor immunological memory created by the endemic coronaviruses, immunity against other common pathogens might offer an alternative explanation. Here, we utilize a combination of epitope prediction and similarity to common human pathogens to identify potential sources of the SARS-CoV-2 T cell memory. Although beta-coronaviruses are the most likely candidates to explain the pre-existing SARS-CoV-2 reactive T cells in uninfected individuals, the SARS-CoV-2 epitopes with the highest similarity to those from beta-coronaviruses are confined to replication associated proteins-not the host interacting S-protein. Thus, our study suggests that the observed SARS-CoV-2 pre-formed immunity to structural proteins is not driven by near-identical epitopes.


Subject(s)
Coronavirus Infections/immunology , Epitopes/immunology , Immunologic Memory , Pneumonia, Viral/immunology , T-Lymphocytes/immunology , Viral Structural Proteins/immunology , Antigens, Viral/chemistry , Antigens, Viral/immunology , Betacoronavirus/immunology , COVID-19 , Epitopes/chemistry , Humans , Pandemics , SARS-CoV-2 , Viral Structural Proteins/chemistry
14.
Infect Genet Evol ; 85: 104517, 2020 11.
Article in English | MEDLINE | ID: covidwho-737519

ABSTRACT

The present study aimed to predict a novel chimeric vaccine by simultaneously targeting four major structural proteins via the establishment of ancestral relationship among different strains of coronaviruses. Conserved regions from the homologous protein sets of spike glycoprotein, membrane protein, envelope protein and nucleocapsid protein were identified through multiple sequence alignment. The phylogeny analyses of whole genome stated that four proteins reflected the close ancestral relation of SARS-CoV-2 to SARS-COV-1 and bat coronavirus. Numerous immunogenic epitopes (both T cell and B cell) were generated from the common fragments which were further ranked on the basis of antigenicity, transmembrane topology, conservancy level, toxicity and allergenicity pattern and population coverage analysis. Top putative epitopes were combined with appropriate adjuvants and linkers to construct a novel multiepitope subunit vaccine against COVID-19. The designed constructs were characterized based on physicochemical properties, allergenicity, antigenicity and solubility which revealed the superiority of construct V3 in terms safety and efficacy. Essential molecular dynamics and normal mode analysis confirmed minimal deformability of the refined model at molecular level. In addition, disulfide engineering was investigated to accelerate the stability of the protein. Molecular docking study ensured high binding affinity between construct V3 and HLA cells, as well as with different host receptors. Microbial expression and translational efficacy of the constructs were checked using pET28a(+) vector of E. coli strain K12. However, the in vivo and in vitro validation of suggested vaccine molecule might be ensured with wet lab trials using model animals for the implementation of the presented data.


Subject(s)
Epitopes, B-Lymphocyte/genetics , Epitopes, T-Lymphocyte/genetics , SARS-CoV-2/classification , Vaccines, Subunit/genetics , Viral Structural Proteins/genetics , Epitopes, B-Lymphocyte/immunology , Epitopes, T-Lymphocyte/immunology , Escherichia coli/genetics , Escherichia coli/growth & development , Evolution, Molecular , Genome, Viral , Humans , Models, Molecular , Molecular Docking Simulation , Molecular Dynamics Simulation , Phylogeny , Protein Conformation , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Vaccines, Subunit/chemistry , Vaccines, Subunit/metabolism , Viral Structural Proteins/chemistry , Viral Structural Proteins/immunology , Viral Vaccines/chemistry , Viral Vaccines/genetics , Viral Vaccines/metabolism
15.
J Clin Virol ; 129: 104544, 2020 08.
Article in English | MEDLINE | ID: covidwho-634673

ABSTRACT

The emergence of the severe acute respiratory syndrome coronavirus-2 (SARS CoV-2) has been followed by the rapid development of antibody tests. To assess the utility of the tests for clinical use and seroepidemiologic studies, we examined the sensitivity of commercial antibody tests from Roche, Abbott, Novatec, Virotech Siemens, Euroimmun, and Mediagnost in a prospective diagnostic study. The tests were evaluated with 73 sera from SARS CoV-2 RNA positive individuals with mild to moderate disease or asymptomatic infection. Sera were obtained at 2-3 weeks (N = 25) or > 4 weeks (N = 48) after symptom onset and viral RNA test. The overall sensitivity of the tests ranged from 64.4-93.2%. The most sensitive assays recognized 95.8-100 % of the sera obtained after 4 weeks or later. Sera drawn at 2-3 weeks were recognized with lower sensitivity indicating that the optimal time point for serologic testing is later than 3 weeks after onset of the disease. Nucleoprotein- and glycoproteinbased assays had similar sensitivity indicating that tests with both antigens are suitable for serological diagnostics. Breakdown of the test results showed that nucleoprotein- and glycoprotein-based tests of comparable sensitivity reacted with different sets of sera. The observation indicates that a combination of nucleoprotein- and glycoprotein-based tests would increase the percentage of positive results.


Subject(s)
Antibodies, Viral/blood , Antigens, Viral/immunology , Betacoronavirus/isolation & purification , Clinical Laboratory Techniques/methods , Coronavirus Infections/diagnosis , Pneumonia, Viral/diagnosis , Serologic Tests/methods , Viral Structural Proteins/immunology , Betacoronavirus/immunology , COVID-19 , COVID-19 Testing , Glycoproteins/immunology , Humans , Nucleoproteins/immunology , Pandemics , Prospective Studies , SARS-CoV-2 , Sensitivity and Specificity , Time Factors
SELECTION OF CITATIONS
SEARCH DETAIL
...