RESUMO
Numerous commercial tests for the serological diagnosis of COVID-19 have been produced in recent years. However, it is important to note that these tests exhibit significant variability in their sensitivity, specificity, and accuracy of results. Therefore, the objective of this study was to utilize bioinformatics tools to map SARS-CoV-2 peptides, with the goal of developing a new serological diagnostic test for COVID-19. Two peptides from the S protein and one from the N protein were selected and characterized in silico, chemically synthesized, and used as a serological diagnostic tool to detect IgM, IgG, and IgA anti-SARS-CoV-2 antibodies through the ELISA technique, confirmed as positive and negative samples by RT-qPCR or serology by ELISA. The results showed a sensitivity, specificity, Positive Predictive Value and Negative Predictive Value of 100% (p < 00001, 95% CI) for the proposed test. Although preliminary, this study brings proof-of-concept results that are consistent with the high-performance rates of the ELISA test when compared to other well-established methods for diagnosing COVID-19.
Assuntos
Anticorpos Antivirais , Teste Sorológico para COVID-19 , COVID-19 , Proteínas do Nucleocapsídeo de Coronavírus , Ensaio de Imunoadsorção Enzimática , SARS-CoV-2 , Sensibilidade e Especificidade , Glicoproteína da Espícula de Coronavírus , Humanos , COVID-19/diagnóstico , SARS-CoV-2/imunologia , SARS-CoV-2/isolamento & purificação , SARS-CoV-2/genética , Anticorpos Antivirais/sangue , Glicoproteína da Espícula de Coronavírus/imunologia , Teste Sorológico para COVID-19/métodos , Ensaio de Imunoadsorção Enzimática/métodos , Proteínas do Nucleocapsídeo de Coronavírus/imunologia , Fosfoproteínas/imunologia , Imunoglobulina M/sangue , Peptídeos/imunologia , Peptídeos/química , Imunoglobulina G/sangue , Biologia Computacional/métodosRESUMO
COVID-19, caused by the SARS-COV-2 virus, induces numerous immunological reactions linked to the severity of the clinical condition of those infected. The surface Spike protein (S protein) present in Sars-CoV-2 is responsible for the infection of host cells. This protein presents a high rate of mutations, which can increase virus transmissibility, infectivity, and immune evasion. Therefore, we propose to evaluate, using immunoinformatic techniques, the predicted epitopes for the S protein of seven variants of Sars-CoV-2. MHC class I and II epitopes were predicted and further assessed for their immunogenicity, interferon-gamma (IFN-γ) inducing capacity, and antigenicity. For B cells, linear and structural epitopes were predicted. For class I MHC epitopes, 40 epitopes were found for the clades of Wuhan, Clade 2, Clade 3, and 20AEU.1, Gamma, and Delta, in addition to 38 epitopes for Alpha and 44 for Omicron. For MHC II, there were differentially predicted epitopes for all variants and eight equally predicted epitopes. These were evaluated for differences in the MHC II alleles to which they would bind. Regarding B cell epitopes, 16 were found in the Wuhan variant, 14 in 22AEU.1 and in Clade 3, 15 in Clade 2, 11 in Alpha and Delta, 13 in Gamma, and 9 in Omicron. When compared, there was a reduction in the number of predicted epitopes concerning the Spike protein, mainly in the Delta and Omicron variants. These findings corroborate the need for updates seen today in bivalent mRNA vaccines against COVID-19 to promote a targeted immune response to the main circulating variant, Omicron, leading to more robust protection against this virus and avoiding cases of reinfection. When analyzing the specific epitopes for the RBD region of the spike protein, the Omicron variant did not present a B lymphocyte epitope from position 390, whereas the epitope at position 493 for MHC was predicted only for the Alpha, Gamma, and Omicron variants.
Assuntos
COVID-19 , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , SARS-CoV-2/imunologia , SARS-CoV-2/genética , Humanos , Glicoproteína da Espícula de Coronavírus/imunologia , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/química , COVID-19/imunologia , COVID-19/virologia , COVID-19/prevenção & controle , Brasil , Epitopos de Linfócito B/imunologia , Epitopos de Linfócito B/química , Epitopos/imunologia , Epitopos/química , Interferon gama/imunologia , Antígenos de Histocompatibilidade Classe II/imunologia , Antígenos de Histocompatibilidade Classe II/genéticaRESUMO
Abstract Covid-19 is a respiratory disease caused by the SARS-CoV-2 virus. The high rate of contagion and the spread of the virus in the population make the early detection of the pathogen the means for the adequate targeting of infection control measures. WHO directs sample collection on upper respiratory specimens, including nasopharyngeal and oropharyngeal swab or wash in ambulatory patients, as well as lower respiratory specimens: sputum and/or endotracheal aspirate or bronchoalveolar lavage, in addition to citing blood and feces. Among the various sample collection methods, saliva has been investigated and reported as a potential source for diagnosis. Thus, we propose to evaluate the current scenario, based on recent publications on the perspective of detecting SARS-CoV-2 in saliva as a diagnostic method for Covid-19. The detection of SARS-CoV-2 through saliva seems to be very promising, although obstacles such as the technique and the location of the collection and the sample size of the research carried out so far may present a limitation for its use. The current scenario presents saliva as a reliable method for the detection of SARS-CoV-2, due to the ease of obtaining the samples, the possibility of self-collection, low cost because there is no need to use specific equipment, in addition to reducing the risk of transmission for health professionals.
Assuntos
Doenças Respiratórias/patologia , Saliva/microbiologia , Infecções por Coronavirus/patologia , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave , Diagnóstico , Brasil/epidemiologia , Controle de Infecções , Tecnologia de Baixo Custo , BetacoronavirusAssuntos
Anticorpos Facilitadores/imunologia , Imunidade Coletiva/imunologia , Vacinas Virais/imunologia , Infecção por Zika virus , Zika virus/imunologia , Brasil/epidemiologia , Surtos de Doenças , Humanos , Fatores de Tempo , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/prevenção & controle , Infecção por Zika virus/virologiaRESUMO
BACKGROUND: DENV infection can induce different clinical manifestations varying from mild forms to dengue fever (DF) or the severe hemorrhagic fever (DHF). Several factors are involved in the progression from DF to DHF. No marker is available to predict this progression. Such biomarker could allow a suitable medical care at the beginning of the infection, improving patient prognosis. OBJECTIVES: The aim of this study was to compare the serum expression levels of acute phase proteins in a well-established cohort of dengue fever (DF) and dengue hemorrhagic fever (DHF) patients, in order to individuate a prognostic marker of diseases severity. STUDY DESIGN: The serum levels of 36 cytokines, chemokines and acute phase proteins were determined in DF and DHF patients and compared to healthy volunteers using a multiplex protein array and near-infrared (NIR) fluorescence detection. Serum levels of IL-1ra, IL-23, MIF, sCD40 ligand, IP-10 and GRO-α were also determined by ELISA. RESULTS: At the early stages of infection, GRO-α and IP-10 expression levels were different in DF compared to DHF patients. Besides, GRO-α was positively correlated with platelet counts and IP-10 was negatively correlated with total protein levels. CONCLUSIONS: These findings suggest that high levels of GRO-α during acute DENV infection may be associated with a good prognosis, while high levels of IP-10 may be a warning sign of infection severity.
Assuntos
Biomarcadores/sangue , Citocinas/sangue , Dengue/patologia , Análise Serial de Proteínas , Adolescente , Adulto , Feminino , Humanos , Masculino , Prognóstico , Soro/química , Voluntários , Adulto JovemAssuntos
Humanos , Anticorpos Facilitadores/imunologia , Imunidade Coletiva/imunologia , Vacinas Virais/imunologia , Zika virus/imunologia , Brasil/epidemiologia , Surtos de Doenças , Fatores de Tempo , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/prevenção & controle , Infecção por Zika virus/virologiaRESUMO
Dengue is an acute febrile disease caused by the mosquito-borne dengue virus (DENV) that according to clinical manifestations can be classified as asymptomatic, mild or severe dengue. Severe dengue cases have been associated with an unbalanced immune response characterised by an over secretion of inflammatory cytokines. In the present study we measured type I interferon (IFN-I) transcript and circulating levels in primary and secondary DENV infected patients. We observed that dengue fever (DF) and dengue haemorrhagic fever (DHF) patients express IFN-I differently. While DF and DHF patients express interferon-α similarly (52,71 ± 7,40 and 49,05 ± 7,70, respectively), IFN- β were associated with primary DHF patients. On the other hand, secondary DHF patients were not able to secrete large amounts of IFN- β which in turn may have influenced the high-level of viraemia. Our results suggest that, in patients from our cohort, infection by DENV serotype 3 elicits an innate response characterised by higher levels of IFN- β in the DHF patients with primary infection, which could contribute to control infection evidenced by the low-level of viraemia in these patients. The present findings may contribute to shed light in the role of innate immune response in dengue pathogenesis.
Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto , Adulto Jovem , Interferon beta/sangue , Dengue Grave/sangue , Doença Aguda , Brasil , Dengue Grave/imunologiaRESUMO
Dengue is an acute febrile disease caused by the mosquito-borne dengue virus (DENV) that according to clinical manifestations can be classified as asymptomatic, mild or severe dengue. Severe dengue cases have been associated with an unbalanced immune response characterised by an over secretion of inflammatory cytokines. In the present study we measured type I interferon (IFN-I) transcript and circulating levels in primary and secondary DENV infected patients. We observed that dengue fever (DF) and dengue haemorrhagic fever (DHF) patients express IFN-I differently. While DF and DHF patients express interferon-α similarly (52,71 ± 7,40 and 49,05 ± 7,70, respectively), IFN- ß were associated with primary DHF patients. On the other hand, secondary DHF patients were not able to secrete large amounts of IFN- ß which in turn may have influenced the high-level of viraemia. Our results suggest that, in patients from our cohort, infection by DENV serotype 3 elicits an innate response characterised by higher levels of IFN- ß in the DHF patients with primary infection, which could contribute to control infection evidenced by the low-level of viraemia in these patients. The present findings may contribute to shed light in the role of innate immune response in dengue pathogenesis.