Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 13.380
Filtrar
1.
Front Immunol ; 12: 635701, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34489923

RESUMO

Serological testing is a powerful tool in epidemiological studies for understanding viral circulation and assessing the effectiveness of virus control measures, as is the case of SARS-CoV-2, the pathogenic agent of COVID-19. Immunoassays can quantitatively reveal the concentration of antiviral antibodies. The assessment of antiviral antibody titers may provide information on virus exposure, and changes in IgG levels are also indicative of a reduction in viral circulation. In this work, we describe a serological study for the evaluation of antiviral IgG and IgM antibodies and their correlation with antiviral activity. The serological assay for IgG detection used two SARS-CoV-2 proteins as antigens, the nucleocapsid N protein and the 3CL protease. Cross-reactivity tests in animals have shown high selectivity for detection of antiviral antibodies, using both the N and 3CL antigens. Using samples of human serum from individuals previously diagnosed by PCR for COVID-19, we observed high sensitivity of the ELISA assay. Serological results with human samples also suggest that the combination of higher titers of antiviral IgG antibodies to different antigen targets may be associated with greater neutralization activity, which can be enhanced in the presence of antiviral IgM antibodies.


Assuntos
Anticorpos Antivirais/imunologia , Teste Sorológico para COVID-19/métodos , COVID-19/diagnóstico , COVID-19/prevenção & controle , Vigilância Imunológica , SARS-CoV-2/imunologia , Animais , Anticorpos Antivirais/sangue , Antígenos Virais/imunologia , COVID-19/epidemiologia , COVID-19/imunologia , Teste Sorológico para COVID-19/normas , Reações Cruzadas , Vírus da Dengue/imunologia , Ensaio de Imunoadsorção Enzimática/métodos , Ensaio de Imunoadsorção Enzimática/normas , Feminino , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Camundongos , Camundongos Endogâmicos BALB C , Sensibilidade e Especificidade , Zika virus/imunologia
2.
Front Immunol ; 12: 723585, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34489974

RESUMO

Objectives: Our objective was to determine the antibody and cytokine profiles in different COVID-19 patients. Methods: COVID-19 patients with different clinical classifications were enrolled in this study. The level of IgG antibodies, IgA, IgM, IgE, and IgG subclasses targeting N and S proteins were tested using ELISA. Neutralizing antibody titers were determined by using a toxin neutralization assay (TNA) with live SARS-CoV-2. The concentrations of 8 cytokines, including IL-2, IL-4, IL-6, IL-10, CCL2, CXCL10, IFN-γ, and TNF-α, were measured using the Protein Sample Ella-Simple ELISA system. The differences in antibodies and cytokines between severe and moderate patients were compared by t-tests or Mann-Whitney tests. Results: A total of 79 COVID-19 patients, including 49 moderate patients and 30 severe patients, were enrolled. Compared with those in moderate patients, neutralizing antibody and IgG-S antibody titers in severe patients were significantly higher. The concentration of IgG-N antibody was significantly higher than that of IgG-S antibody in COVID-19 patients. There was a significant difference in the distribution of IgG subclass antibodies between moderate patients and severe patients. The positive ratio of anti-S protein IgG3 is significantly more than anti-N protein IgG3, while the anti-S protein IgG4 positive rate is significantly less than the anti-N protein IgG4 positive rate. IL-2 was lower in COVID-19 patients than in healthy individuals, while IL-4, IL-6, CCL2, IFN-γ, and TNF-α were higher in COVID-19 patients than in healthy individuals. IL-6 was significantly higher in severe patients than in moderate patients. The antibody level of anti-S protein was positively correlated with the titer of neutralizing antibody, but there was no relationship between cytokines and neutralizing antibody. Conclusions: Our findings show the severe COVID-19 patients' antibody levels were stronger than those of moderate patients, and a cytokine storm is associated with COVID-19 severity. There was a difference in immunoglobulin type between anti-S protein antibodies and anti-N protein antibodies in COVID-19 patients. And clarified the value of the profile in critical prevention.


Assuntos
Anticorpos Antivirais/sangue , COVID-19/imunologia , Citocinas/sangue , SARS-CoV-2/imunologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Neutralizantes/sangue , COVID-19/classificação , Proteínas do Nucleocapsídeo de Coronavírus/imunologia , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Imunoglobulina A/sangue , Imunoglobulina E/sangue , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Masculino , Pessoa de Meia-Idade , Índice de Gravidade de Doença , Glicoproteína da Espícula de Coronavírus/imunologia
3.
PLoS One ; 16(9): e0257351, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34520491

RESUMO

COVID-19 is the name of the acute respiratory disease caused by the new coronavirus SARS-CoV-2, a close relative of those that caused the severe outbreaks of SARS and MERS several years ago. Since first appearance on December of 2019, the COVID-19 pandemic has cause extremely high levels of mortality, morbidity, global economic breakdown, and the consequent human suffering. The main diagnostic test for the confirmation of symptomatic individuals is the detection of viral RNA by reverse transcriptase-quantitative real time PCR (RT-PCR). Additionally, serology techniques, such as ELISA are useful to measure the antibodies produced in humans after contact with the virus, as well as the direct presence of viral antigens. In this study we aim to assemble and evaluate four ELISA assays to measure the presence of IgG or IgM specific for the viral Spike protein in COVID-19 patients, using either the full recombinant SARS-CoV-2 Spike protein or the fragment corresponding to the receptor binding domain. As a control, we analyzed a group of pre-pandemic serum samples obtained before 2017. Strong reactivity was observed against both antigens. A few pre-pandemic samples displayed high OD values, suggesting the possibility of some cross reactivity. All four assays show very good repeatability, both intra- and inter-assay. Receiver operating characteristic analysis allowed the definition of cutoffs and evaluation of performance for each ELISA by estimation of the area under the curve. This performance parameter was high for all tests (AUC range: 0.98-0.99). Multiple comparisons between tests revealed no significant difference between each other (P values: 0.24-0.95). Our results show that both antigens are effective to detect both specific IgG and IgM antibodies, with high sensitivity (range 0.92-0.99), specificity (range 0.93-0.97) and congruence with the RT-PCR test (Cohen´s Kappa range 0.87-0.93). These assays will allow health authorities to have a new tool to estimate seroprevalence, in order to manage and improve the severe sanitary situation caused by this virus.


Assuntos
Anticorpos Antivirais/sangue , COVID-19/diagnóstico , Ensaio de Imunoadsorção Enzimática/métodos , COVID-19/epidemiologia , COVID-19/virologia , Teste de Ácido Nucleico para COVID-19 , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Panamá/epidemiologia , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética
4.
Mil Med Res ; 8(1): 47, 2021 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-34465396

RESUMO

SARS-CoV-2 is a newly identified member of the coronavirus family that has caused the Coronavirus disease 2019 (COVID-19) pandemic. This rapidly evolving and unrelenting SARS-CoV-2 has disrupted the lives and livelihoods of millions worldwide. As of 23 August 2021, a total of 211,373,303 COVID-19 cases have been confirmed globally with a death toll of 4,424,341. A strong understanding of the infection pathway of SARS-CoV-2, and how our immune system responds to the virus is highly pertinent for guiding the development and improvement of effective treatments. In this review, we discuss the current understanding of neutralising antibodies (NAbs) and their implications in clinical practice. The aspects include the pathophysiology of the immune response, particularly humoral adaptive immunity and the roles of NAbs from B cells in infection clearance. We summarise the onset and persistence of IgA, IgM and IgG antibodies, and we explore their roles in neutralising SARS-CoV-2, their persistence in convalescent individuals, and in reinfection. Furthermore, we also review the applications of neutralising antibodies in the clinical setting-from predictors of disease severity to serological testing to vaccinations, and finally in therapeutics such as convalescent plasma infusion.


Assuntos
Anticorpos Neutralizantes/uso terapêutico , COVID-19/terapia , Imunidade Humoral , SARS-CoV-2/imunologia , Anticorpos Neutralizantes/imunologia , COVID-19/epidemiologia , COVID-19/imunologia , Humanos , Imunização Passiva , Imunoglobulina A/sangue , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Pandemias , Glicoproteína da Espícula de Coronavírus/imunologia
5.
PLoS One ; 16(9): e0248444, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34473705

RESUMO

The pandemic of novel coronavirus disease COVID-19 is rapidly expanding across the world. A positive result of antibody tests suggests that the individual has potentially been exposed to SARS-CoV-2, thus allowing to identify asymptomatic infections and determine the seroprevalence in a given population. The aim of this study was to evaluate the performances of a newly developed high throughput immunoassay for anti-SARS-CoV-2 IgM antibody detection on the Luminex MAGPIX platform. Clinical agreement studies were performed in 42 COVID-19 patient serum samples and 162 negative donor serum/plasma samples. Positive percent agreement (PPA) was 42.86% (95% CI: 9.90% to 81.59%), 71.43% (95% CI: 29.04% to 96.33%), and 28.57% (95% CI: 13.22% to 48.67%) for samples collected on 0-7 days, 8-14 days, and 2-8 weeks from symptom onset, respectively. Negative Percent Agreement (NPA) was 97.53% (95% CI: 93.80% to 99.32%). There was no cross-reactivity with the SARS-CoV-2 IgG antibody. Hemoglobin (200 mg/dL), bilirubin (2 mg/dL), triglyceride (250 mg/dL) and EDTA (10 mM) showed no significant interfering effect on this assay. In conclusion, an anti-SARS-CoV-2 IgM antibody assay with high sensitivity and specificity has been developed. With the high throughput, this assay will speed up the anti-SARS-CoV-2 IgM testing.


Assuntos
Anticorpos Antivirais/imunologia , Teste Sorológico para COVID-19/métodos , Imunoensaio/métodos , Imunoglobulina M/imunologia , Microesferas , SARS-CoV-2/imunologia , Anticorpos Antivirais/sangue , Ensaios de Triagem em Larga Escala/métodos , Humanos , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Imunoglobulina M/sangue , Curva ROC , SARS-CoV-2/fisiologia
6.
Nat Commun ; 12(1): 4740, 2021 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-34362897

RESUMO

Unraveling the long-term kinetics of antibodies to SARS-CoV-2 and the individual characteristics influencing it, including the impact of pre-existing antibodies to human coronaviruses causing common cold (HCoVs), is essential to understand protective immunity to COVID-19 and devise effective surveillance strategies. IgM, IgA and IgG levels against six SARS-CoV-2 antigens and the nucleocapsid antigen of the four HCoV (229E, NL63, OC43 and HKU1) were quantified by Luminex, and antibody neutralization capacity was assessed by flow cytometry, in a cohort of health care workers followed up to 7 months (N = 578). Seroprevalence increases over time from 13.5% (month 0) and 15.6% (month 1) to 16.4% (month 6). Levels of antibodies, including those with neutralizing capacity, are stable over time, except IgG to nucleocapsid antigen and IgM levels that wane. After the peak response, anti-spike antibody levels increase from ~150 days post-symptom onset in all individuals (73% for IgG), in the absence of any evidence of re-exposure. IgG and IgA to HCoV are significantly higher in asymptomatic than symptomatic seropositive individuals. Thus, pre-existing cross-reactive HCoVs antibodies could have a protective effect against SARS-CoV-2 infection and COVID-19 disease.


Assuntos
Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Coronavirus Humano 229E/imunologia , Coronavirus Humano NL63/imunologia , SARS-CoV-2/imunologia , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Antígenos Virais/imunologia , COVID-19/imunologia , COVID-19/prevenção & controle , Resfriado Comum/imunologia , Resfriado Comum/virologia , Proteção Cruzada/imunologia , Humanos , Imunoglobulina A/sangue , Imunoglobulina G/sangue , Imunoglobulina M/sangue
7.
PLoS One ; 16(8): e0255796, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34375345

RESUMO

Serological assays to detect antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) might contribute to confirming the suspected coronavirus disease 2019 (COVID-19) in patients not detected with molecular assays. Human antibodies that target the host angiotensin-converting enzyme 2-binding domain of the viral spike protein are a target for serodiagnosis and therapeutics. This study aimed to characterize the classes and subclasses of antibody responses to a recombinant receptor-binding protein (RBD) of SARS-CoV-2 in COVID-19 patients and investigated the reactivity of these antibodies in patients with other tropical infections and healthy individuals in Thailand. ELISAs for IgM, IgA, IgG and IgG subclasses based on RBD antigen were developed and tested with time series of 27 serum samples from 15 patients with COVID-19 and 60 samples from pre-COVID-19 outbreaks including acute dengue fever, murine typhus, influenza, leptospirosis and healthy individuals. Both RBD-specific IgA and IgG were detected in only 21% of the COVID-19 patients in the acute phase. The median IgA and IgG levels were significantly higher in the convalescent serum sample compared to the acute serum sample (P < 0.05). We observed the highest correlation between levels of IgG and IgA (rho = 0. 92). IgG1 and IgG3 were the major IgG subclasses detected in SARS-CoV-2 infection. Only acute IgG3 level was negatively associated with viral detection based on RT-PCR of ORF1ab gene (rho = -0.57). The median IgA and IgG levels in convalescence sera of COVID-19 patients were significantly higher than healthy individuals and convalescent sera of other febrile infectious patients. The analyses of antibody classes and subclasses provide insights into human immune responses against SARS-CoV-2 during natural infection and interpretation of antibody assays.


Assuntos
Anticorpos Antivirais/sangue , Formação de Anticorpos , COVID-19/patologia , Isotipos de Imunoglobulinas/sangue , Glicoproteína da Espícula de Coronavírus/imunologia , Adulto , Idoso , COVID-19/sangue , COVID-19/virologia , Feminino , Humanos , Imunoglobulina A/sangue , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Domínios Proteicos/imunologia , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/imunologia , SARS-CoV-2/isolamento & purificação , SARS-CoV-2/metabolismo , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/metabolismo , Tailândia , Adulto Jovem
8.
BMC Infect Dis ; 21(1): 835, 2021 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-34412620

RESUMO

BACKGROUND: Seroprevalence of anti-SARS-CoV-2 antibodies is now available in several world regions to better estimate transmission dynamics. However, to date, there is no epidemiological data regarding anti-SARS-CoV-2 prevalence in Mexico. Therefore, we aimed to determine the prevalence of anti-SARS-CoV-2 antibodies and define the clinical and demographic characteristics associated with seroprevalence. METHODS: We conducted a cross-sectional serological survey in Ciudad Guadalupe, NL, Mexico. City government employees voluntarily participated during July 2020. Demographic and clinical characteristics were collected at the time of blood sampling to analyze the associated characteristics. IgM/IgG antibodies were determined using a qualitative chemiluminescent immunoassay. Descriptive statistics were used for categorical and continuous variables. Statistical significance was tested using the Chi-squared test, Student's t-test and the Mann-Whitney. Logistic regression models and the odds ratios (adjusted and unadjusted) were used to estimate the association of demographic and clinical characteristics. RESULTS: Of the 3,268 participants included, 193 (5.9%, 95% CI 5.1-6.8) tested positive for IgM/IgG against SARS-CoV-2. Sex, city of residence, and comorbidities did not show any association with having IgM/IgG antibodies. A total of 114 out of 193 (59.1%) subjects with a positive test were asymptomatic, and the odds of being positive were higher in those who reported symptoms of COVID-19 in the previous four weeks to the survey (OR 4.1, 95% CI 2.9-5.5). CONCLUSIONS: There is a low rate of SARS-CoV-2 infection among government employees that have continuously been working during the pandemic. Six in ten infections were asymptomatic, and seroprevalence is low and still far from herd immunity. Epidemiological surveillance and preventive measures should be mandatory.


Assuntos
Teste Sorológico para COVID-19/métodos , COVID-19/epidemiologia , Imunoglobulina G/sangue , Imunoglobulina M/sangue , SARS-CoV-2/isolamento & purificação , Anticorpos Antivirais/sangue , COVID-19/imunologia , Estudos Transversais , Humanos , México/epidemiologia , Pandemias , Prevalência , SARS-CoV-2/imunologia , Estudos Soroepidemiológicos
9.
Iran J Allergy Asthma Immunol ; 20(4): 394-401, 2021 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-34418893

RESUMO

Considering the increasing prevalence and burden of coronavirus disease 2019 (COVID-19) disease and false-negative results in routine reverse transcription-polymerase chain reaction (RT-PCR) tests, additional diagnostic methods are needed to diagnose active cases of this disease. This prospective study was conducted on patients, in whom clinical and radiological symptoms/signs were in favor of COVID-19 while their first PCR test was negative. Later on, a second RT-PCR was performed and serological evaluation was carried out and results were compared with each other. Out of 707 patients who had been referred to the hospital and were clinically and radiologically suspicious of disease, 137 patients with negative RT-PCR tests entered the study. RT-PCR assay became positive for the second time in 45 (32.8%). Anti-COVID-19 IgM and IgG antibodies were positive in 83 (60.6%) and 86 (62.8%) patients, respectively. Finally, it was determined that serological test was diagnostic in 73% of patients and the diagnostic yield of serology was significantly higher after the first week of illness (54.8% in the first week and 88% after that). Taking advantage of both serological tests and RT-PCR helps in diagnosing 83.9% of cases. Based on the present study, the serology may be useful as a complementary test and in parallel to RT-PCR assay for diagnosis of COVID-19 among admitted symptomatic cases.


Assuntos
Teste para COVID-19 , COVID-19/diagnóstico , Hospitalização , Adulto , Idoso , Anticorpos Antivirais/sangue , Feminino , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , RNA Viral/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa , SARS-CoV-2/genética , SARS-CoV-2/imunologia , SARS-CoV-2/isolamento & purificação , Sensibilidade e Especificidade
10.
Ann Clin Lab Sci ; 51(4): 540-545, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34452893

RESUMO

OBJECTIVE: Mycoplasma pneumoniae (M. pneumoniae), an extracellular pathogen lacking a cell wall, causes respiratory infection in adults and children and has been implicated in asthma exacerbation; immunoglobulin (Ig) E may be involved in these exacerbations. Specific IgM and IgG immune response to M. pneumoniae has been reported, but less is known about IgE M. pneumoniae antibody (Ab) responses in asthma. Previous studies in our laboratory demonstrated that asthmatic children have increased IgM M. pneumoniae levels, but not IgE. Thus, we sought to investigate whether past M. pneumoniae infection triggers production of M. pneumoniae-specific IgE Abs in adult subjects with/without asthma. METHODS: M. pneumoniae- IgE and -IgM Ab responses were studied in adult asthmatic (N=22) and non-asthmatic (N=22) subjects (ELISA). Data are reported as antibody index. Threshold detection levels: IgE, IgM: 0.2, 0.9, respectively. RESULTS: M. pneumoniae-IgE Ab levels were low and below the threshold of detection in both asthmatic and non-asthmatics (0.002±0.008 vs. 0.02±0.03; P=0.021). However, specific-IgM levels were slightly higher in non-asthmatics compared with asthmatics (0.96±0.37 vs. 0.79±0.31; P=0.054). M. pneumoniae-IgM Ab positivity was similar in both groups (P=1.0). CONCLUSION: IgM M. pneumoniae Abs may play an important role in non-asthma and persist for months after acute infection. IgE M. pneumoniae Abs may play a less important role in both groups.


Assuntos
Anticorpos Antibacterianos/sangue , Asma/imunologia , Imunoglobulina E/imunologia , Imunoglobulina M/sangue , Mycoplasma pneumoniae/imunologia , Pneumonia por Mycoplasma/imunologia , Adulto , Anticorpos Antibacterianos/imunologia , Asma/sangue , Asma/complicações , Asma/epidemiologia , Estudos de Casos e Controles , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , New York/epidemiologia , Pneumonia por Mycoplasma/sangue , Pneumonia por Mycoplasma/epidemiologia , Pneumonia por Mycoplasma/etiologia , Prognóstico
11.
Clin Immunol ; 230: 108814, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34343708

RESUMO

Better understanding of antibody responses against SARS-CoV-2 after natural infection might provide valuable insights into the future implementation of vaccination policies. Longitudinal analysis of IgG antibody titers was carried out in 32 recovered COVID-19 patients based in the Umbria region of Italy for 14 months after Mild and Moderately-Severe infection.Two FDA-approved immunoassays against SARS-CoV-2 Nucleocapsid protein (NCP) and anti-spike-receptor binding domain (S-RBD) were used for sequential serological tests at different time points. The demographics,clinical history and symptom profile associated with the magnitude and longevity of antibody responses were also analyzed. Anti-S-RBD IgG persisted in 96.8% (31 of 32) subjects at 14 months. Patients reporting loss of smell and taste during the clinical course of the disease developed significantly higher antibody titers. Anti-NCP IgG seronegative patients(n=7) at 10 months, tested positive for anti-S-RBD IgG at 12,13 and 14 months emphasizing on a higher false-negative rate for NCP protein-based antibody assays. This study also highlights the importance of adopting specific immunoassays for routine estimation of antibody titers and the decreased rate of re-infections in recovered patients.


Assuntos
Anticorpos Antivirais/sangue , Vacinas contra COVID-19/imunologia , COVID-19/imunologia , COVID-19/virologia , Imunoglobulina G/sangue , SARS-CoV-2/imunologia , Adulto , COVID-19/sangue , COVID-19/prevenção & controle , Vacinas contra COVID-19/administração & dosagem , Comorbidade , Feminino , Humanos , Imunoglobulina M/sangue , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Fatores de Tempo
12.
Front Immunol ; 12: 696370, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34386006

RESUMO

The COVID-19 pandemic is caused by SARS-CoV-2, a novel zoonotic coronavirus. Emerging evidence indicates that preexisting humoral immunity against other seasonal human coronaviruses (HCoVs) plays a critical role in the specific antibody response to SARS-CoV-2. However, current work to assess the effects of preexisting and cross-reactive anti-HCoVs antibodies has been limited. To address this issue, we have adapted our previously reported multiplex assay to simultaneously and quantitatively measure anti-HCoV antibodies. The full mPlex-CoV panel covers the spike (S) and nucleocapsid (N) proteins of three highly pathogenic HCoVs (SARS-CoV-1, SARS-CoV-2, MERS) and four human seasonal strains (OC43, HKU1, NL63, 229E). Combining this assay with volumetric absorptive microsampling (VAMS), we measured the anti-HCoV IgG, IgA, and IgM antibodies in fingerstick blood samples. The results demonstrate that the mPlex-CoV assay has high specificity and sensitivity. It can detect strain-specific anti-HCoV antibodies down to 0.1 ng/ml with 4 log assay range and with low intra- and inter-assay coefficients of variation (%CV). We also estimate multiple strain HCoVs IgG, IgA and IgM concentration in VAMS samples in three categories of subjects: pre-COVID-19 (n=21), post-COVID-19 convalescents (n=19), and COVID-19 vaccine recipients (n=14). Using metric multidimensional scaling (MDS) analysis, HCoVs IgG concentrations in fingerstick blood samples were well separated between the pre-COVID-19, post-COVID-19 convalescents, and COVID-19 vaccine recipients. In addition, we demonstrate how multi-dimensional scaling analysis can be used to visualize IgG mediated antibody immunity against multiple human coronaviruses. We conclude that the combination of VAMS and the mPlex-Cov assay is well suited to performing remote study sample collection under pandemic conditions to monitor HCoVs antibody responses in population studies.


Assuntos
Anticorpos Antivirais/sangue , Coronavirus/imunologia , Reações Cruzadas/imunologia , Imunoensaio/métodos , Anticorpos Antivirais/imunologia , Betacoronavirus/imunologia , COVID-19/imunologia , Coronavirus Humano 229E/imunologia , Coronavirus Humano NL63/imunologia , Proteínas do Nucleocapsídeo de Coronavírus/imunologia , Coronavirus Humano OC43/imunologia , Humanos , Imunoglobulina A/sangue , Imunoglobulina A/imunologia , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Imunoglobulina M/sangue , Imunoglobulina M/imunologia , Vírus da SARS/imunologia , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia
13.
J Infect Dev Ctries ; 15(7): 913-917, 2021 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-34343115

RESUMO

Early diagnosis is among the crucial measures to control the spread of SARS-CoV-2 infection. To date, reverse transcription polymerase chain reaction (RT-PCR) is the gold standard for COVID-19 testing, but various factors can affect its performance leading to false negative results. Hereby we present a patient with a high clinical suspicion for COVID-19 and had multiple negative RT-PCR results over 5 days. A 22-year-old woman presented with fever, dry cough, nausea, myalgia, headache, and mild dyspnea. Eleven days before, she was in close contact with her father who had tested positive for COVID-19. RT-PCR on nasopharyngeal and oropharyngeal swabs were performed on day 8, 9, and 12 of illness which all came back negative even after she started having a worsening dyspnea and showing an increased lung opacity from radiographic findings on day 11 of illness. Interestingly, her rapid antibody test (VivaDiag™ COVID-19 IgM/IgG rapid test by VivaChek Biotech (HangZhou,China) was positive for anti-SARS-CoV-2 Ig M and Ig G. Due to the worsening condition, she was referred to a tertiary hospital where her RT PCR result was positive on day 13 of illness. After 28 days from her first symptom, she was discharged from the hospital with improved symptoms and chest X-ray. As conclusions, in patients with high suspicion of COVID-19, repeat swab tests are mandatory if previous tests were negative. The diagnosis and treatment plan of COVID-19 should not solely be based on RT-PCR, but also consider the patient's history, symptoms, laboratory result, and radiographic findings.


Assuntos
Teste de Ácido Nucleico para COVID-19/normas , COVID-19/diagnóstico , Reação em Cadeia da Polimerase Via Transcriptase Reversa/normas , SARS-CoV-2/genética , Anticorpos Antivirais/sangue , COVID-19/virologia , Reações Falso-Negativas , Feminino , Humanos , Imunoglobulina M/sangue , Nasofaringe/virologia , Sensibilidade e Especificidade , Manejo de Espécimes , Fatores de Tempo , Adulto Jovem
14.
mBio ; 12(4): e0097421, 2021 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-34253053

RESUMO

In the coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), more severe outcomes are reported in males than in females, including hospitalizations and deaths. Animal models can provide an opportunity to mechanistically interrogate causes of sex differences in the pathogenesis of SARS-CoV-2. Adult male and female golden Syrian hamsters (8 to 10 weeks of age) were inoculated intranasally with 105 50% tissue culture infective dose (TCID50) of SARS-CoV-2/USA-WA1/2020 and euthanized at several time points during the acute (i.e., virus actively replicating) and recovery (i.e., after the infectious virus has been cleared) phases of infection. There was no mortality, but infected male hamsters experienced greater morbidity, losing a greater percentage of body mass, developed more extensive pneumonia as noted on chest computed tomography, and recovered more slowly than females. Treatment of male hamsters with estradiol did not alter pulmonary damage. Virus titers in respiratory tissues, including nasal turbinates, trachea, and lungs, and pulmonary cytokine concentrations, including interferon-ß (IFN-ß) and tumor necrosis factor-α (TNF-α), were comparable between the sexes. However, during the recovery phase of infection, females mounted 2-fold greater IgM, IgG, and IgA responses against the receptor-binding domain of the spike protein (S-RBD) in both plasma and respiratory tissues. Female hamsters also had significantly greater IgG antibodies against whole-inactivated SARS-CoV-2 and mutant S-RBDs as well as virus-neutralizing antibodies in plasma. The development of an animal model to study COVID-19 sex differences will allow for a greater mechanistic understanding of the SARS-CoV-2-associated sex differences seen in the human population. IMPORTANCE Men experience more severe outcomes from coronavirus disease 2019 (COVID-19) than women. Golden Syrian hamsters were used to explore sex differences in the pathogenesis of a human isolate of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). After inoculation, male hamsters experienced greater sickness, developed more severe lung pathology, and recovered more slowly than females. Sex differences in disease could not be reversed by estradiol treatment in males and were not explained by either virus replication kinetics or the concentrations of inflammatory cytokines in the lungs. During the recovery period, antiviral antibody responses in the respiratory tract and plasma, including to newly emerging SARS-CoV-2 variants, were greater in female than in male hamsters. Greater lung pathology during the acute phase combined with lower antiviral antibody responses during the recovery phase of infection in males than in females illustrate the utility of golden Syrian hamsters as a model to explore sex differences in the pathogenesis of SARS-CoV-2 and vaccine-induced immunity and protection.


Assuntos
Anticorpos Antivirais/sangue , COVID-19/imunologia , Pulmão/patologia , SARS-CoV-2/imunologia , Índice de Gravidade de Doença , Animais , Formação de Anticorpos/imunologia , Cricetinae , Modelos Animais de Doenças , Estradiol/farmacologia , Feminino , Imunoglobulina A/sangue , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Interferon beta/análise , Pulmão/diagnóstico por imagem , Pulmão/virologia , Masculino , Fatores Sexuais , Glicoproteína da Espícula de Coronavírus/imunologia , Fator de Necrose Tumoral alfa/análise , Carga Viral
15.
Sci Rep ; 11(1): 14926, 2021 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-34290350

RESUMO

Infection with SARS-CoV-2, the Betacoronavirus, caused a pandemic that affected the globe negatively. The gold method, RT-PCR, can detect SARS-CoV-2 but it is time-consuming and needs sophisticated equipment and professional personnel. On the other hand, rapid tests offer fast results and can detect anti-SARS-CoV-2 antibodies (Abs). The aim of this study is to develop a new rapid and cost-effective method for the detection of anti-SARS-CoV-2 IgG/IgM Abs. A new top-loading detection device was developed and composed of a small piece of plastic (25 × 25 × 0.5 mm) with an opening in the center, a piece of nitrocellulose (NC) membrane enough to block the opening from one side and adhesive tape to affix the NC to the plastic piece. The NC is blotted with anti-human IgG/IgM and rabbit serum. The device was evaluated against a commercially available IgG/IgM ELISA detection kit using normal, Covid-19-positive, HCV, HBV, and Cytomegalovirus-positive sera. Outcomes demonstrated simplicity, reproducibility, and accuracy of the new device and results can be obtained in less than 5 min. We anticipate our developed assay method to be used widely in point of care before deciding on the use of expensive nucleic acid assays.


Assuntos
COVID-19/diagnóstico , Imunoensaio/métodos , SARS-CoV-2/imunologia , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , COVID-19/sangue , COVID-19/imunologia , Análise Custo-Benefício , Ensaio de Imunoadsorção Enzimática , Humanos , Imunoensaio/instrumentação , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Imunoglobulina M/sangue , Imunoglobulina M/imunologia , Testes Imediatos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
16.
Occup Environ Med ; 78(9): 648-653, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34193594

RESUMO

OBJECTIVES: To assess the prevalence of SARS-CoV-2-specific IgM and IgG antibodies among workers of the three public higher education institutions of Porto, Portugal, up to July 2020. METHODS: A rapid point-of-care test for specific IgM and IgG antibodies of SARS-CoV-2 was offered to all workers (SD Biosensor STANDARD Q COVID-19 IgM/IgG Duo and STANDARD Q COVID-19 IgM/IgG Combo). Testing was performed and a questionnaire was completed by 4592 workers on a voluntary basis from 21 May to 31 July 2020. We computed the apparent IgM, IgG, and combined IgM or IgG prevalence, along with the true prevalence and 95% credible intervals (95% CrI) using Bayesian inference. RESULTS: We found an apparent prevalence of 3.1% for IgM, 1.0% for IgG and 3.9% for either. The estimated true prevalence was 2.0% (95% CrI 0.1% to 4.3%) for IgM, 0.6% (95% CrI 0.0% to 1.3%) for IgG, and 2.5% (95% CrI 0.1% to 5.3%) for IgM or IgG. A SARS-CoV-2 molecular diagnosis was reported by 21 (0.5%) workers; and of these, 90.5% had a reactive IgG result. Seroprevalence was higher among those reporting contacts with confirmed cases, having been quarantined, having a previous molecular negative test or having had symptoms. CONCLUSIONS: The seroprevalence among workers from the three public higher education institutions of Porto after the first wave of the SARS-CoV-2 infection was similar to national estimates for the same age working population. However, the estimated true seroprevalence was approximately five times higher than the reported SARS-CoV-2 infection based on a molecular test.


Assuntos
COVID-19/epidemiologia , SARS-CoV-2/imunologia , Instituições Acadêmicas/estatística & dados numéricos , Local de Trabalho/estatística & dados numéricos , Adulto , Idoso , Anticorpos Antivirais/sangue , COVID-19/sangue , Estudos Transversais , Feminino , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Masculino , Pessoa de Meia-Idade , Portugal/epidemiologia , Prevalência , Estudos Soroepidemiológicos
17.
Int Immunopharmacol ; 98: 107884, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34246041

RESUMO

Performing a cohort-based SARS-CoV-2 antibody assay is crucial for understanding infection status and future decision-making. The objective of this study was to examine consecutive antibody seroprevalence changes among hospital staff, a high-risk population. A two-time survey was performed in May and October 2020 for 545 hospital staff to investigate the changes in the results of the rapid kit test and chemiluminescence immunoassay (CLIA). The seroprevalence of each assay was summarized at both the survey periods. The proportion of seropositive individuals in the CLIA for each survey period and the number of confirmed COVID-19 cases in Central Fukushima were then compared. We chose 515 participants for the analysis. The proportion of IgM seroprevalence in CLIA increased from 0.19% in May to 0.39% in October, and IgG seroprevalence decreased from 0.97% in May to 0.39% in October. The proportion of IgM seroprevalence in the rapid kit test decreased from 7.96% in May to 3.50% in October, and IgG seroprevalence decreased from 7.77% in May to 2.14% in October. The IgG and IgM antibody seroprevalence among hospital staff in rural Central Fukushima decreased; the seroprevalence among hospital staff was consistent with the number of confirmed COVID-19 cases in the Central Fukushima area. Although it is difficult to interpret the results of the antibody assay in a population with a low prior probability, constant follow-up surveys of antibody titers among hospital staff had several merits in obtaining a set of criteria regarding the accuracy of measures against COVID-19 and estimating the COVID-19 infection status among hospital staff.


Assuntos
Anticorpos Antivirais/sangue , Antígenos Virais/imunologia , COVID-19/epidemiologia , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Recursos Humanos em Hospital , Saúde da População Rural , SARS-CoV-2/imunologia , Adulto , Biomarcadores/sangue , COVID-19/diagnóstico , COVID-19/imunologia , COVID-19/virologia , Estudos de Casos e Controles , Feminino , Humanos , Japão/epidemiologia , Masculino , Pessoa de Meia-Idade , Vigilância da População , Estudos Soroepidemiológicos , Fatores de Tempo
18.
Mikrochim Acta ; 188(8): 261, 2021 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-34278534

RESUMO

The ongoing global pandemic of SARS-CoV-2 has promoted to develop novel serological testing technologies since they can be effectively complementary to RT-PCR. Here, a new all-fiber Fresnel reflection microfluidic biosensor (FRMB) was constructed through combining all-fiber optical system, microfluidic chip, and multimode fiber bio-probe. The transmission of the incident light and the collection and transmission of Fresnel reflection light are achieved using a single-multi-mode fiber optic coupler (SMFC) without any other optical separation elements. This compact design greatly simplifies the whole system structure and improves light transmission efficiency, which makes it suitable for the label-free, sensitive, and easy-to-use point-of-care testing (POCT) of targets in nanoliter samples. Based on Fresnel reflection mechanism and immunoassay principle, both the SARS-CoV-2 IgM and IgG antibodies against the SARS-CoV-2 spike protein could be sensitively quantified in 7 min using the secondary antibodies-modified multimode fiber bio-probe. The FRMB performs in one-step, is accurate, label-free, and sensitive in situ/on-site detection of SARS-CoV-2 IgM or IgG in serum with simple dilution only. The limits of detection of SARS-CoV-2 IgM and SARS-CoV-2 IgG were 0.82 ng/mL and 0.45 ng/mL, respectively. Based on our proposed theory, the affinity constants of SARS-CoV-2 IgM or IgG antibody and their respective secondary antibodies were also determined. The FRMB can be readily extended as a universal platform for the label-free, rapid, and sensitive in situ/on-site measurement of other biomarkers and the investigation of biomolecular interaction.


Assuntos
Anticorpos Antivirais/sangue , Técnicas Biossensoriais/métodos , Teste Sorológico para COVID-19/métodos , COVID-19/diagnóstico , Técnicas Analíticas Microfluídicas/métodos , SARS-CoV-2/imunologia , Anticorpos Antivirais/imunologia , Humanos , Imunoensaio/métodos , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Imunoglobulina M/sangue , Imunoglobulina M/imunologia , Limite de Detecção , SARS-CoV-2/química , Sensibilidade e Especificidade , Glicoproteína da Espícula de Coronavírus/imunologia
19.
Mikrochim Acta ; 188(8): 262, 2021 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-34282508

RESUMO

COVID-19 is now a severe threat to global health. Facing this pandemic, we developed a space-encoding microfluidic biochip for high-throughput, rapid, sensitive, simultaneous quantitative detection of SARS-CoV-2 antigen proteins and IgG/IgM antibodies in serum. The proposed immunoassay biochip integrates the advantages of graphene oxide quantum dots (GOQDs) and microfluidic chip and is capable of conducting multiple SARS-CoV-2 antigens or IgG/IgM antibodies of 60 serum samples simultaneously with only 2 µL sample volume of each patient. Fluorescence intensity of antigens and IgG antibody detection at emission wavelength of ~680 nm was used to quantify the target concentration at excitation wavelength of 632 nm, and emission wavelength of ~519 nm was used during the detection of IgM antibodies at excitation wavelength of 488 nm. The method developed has a large linear quantification detection regime of 5 orders of magnitude, an ultralow detection limit of ~0.3 pg/mL under optimized conditions, and less than 10-min qualitative detection time. The proposed biosensing platform will not only greatly facilitate the rapid diagnosis of COVID-19 patients, but also provide a valuable screening approach for infected patients, medical therapy, and vaccine recipients.


Assuntos
Antígenos Virais/sangue , Imunoensaio , Imunoglobulina G/sangue , Imunoglobulina M/sangue , SARS-CoV-2/isolamento & purificação , Reações Antígeno-Anticorpo , Antígenos Virais/imunologia , Humanos , Imunoglobulina G/imunologia , Imunoglobulina M/imunologia , Nanopartículas/química , Tamanho da Partícula , SARS-CoV-2/imunologia , Sensibilidade e Especificidade
20.
J Immunol Methods ; 496: 113096, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34242653

RESUMO

Serology or antibody tests for COVID-19 are designed to detect antibodies (mainly Immunoglobulin M (IgM) and Immunoglobulin G (IgG) produced in response to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS CoV-2) infection. In this study, 30 lateral flow immunoassays were tested using serum or plasma from patients with confirmed SARS CoV-2 infection. Negative serological controls were accessed from a well-characterised bank of sera which were stored prior to February 2020. Operational characteristics and ease of use of the assays are reported. 4/30 (13%) of kits (Zheihang Orient Gene COVID-19 IgG/IgM, Genrui Novel Coronavirus (2019-nCoV) IgG/IgM, Biosynex COVID-19 BSS IgG/IgM, Boson Biotech 2019-nCoV IgG/IgM) were recommended for SAHPRA approval based on kit sensitivity. Of these, only the Orientgene was recommended by SAHPRA in August 2020 for use within the approved national testing algorithm while the remaining three received limited authorization for evaluation. All kits evaluated work on the same basic principle of immunochromatography with minor differences noted in the shape and colour of cartridges, the amount of specimen volume required and the test duration. Performance of the lateral flow tests were similar to sensitivities and specificities reported in other studies. The cassettes of the majority of kits evaluated (90%) detected both IgG and IgM. Only 23% of kits evaluated contained all consumables required for point-of-care testing. The study highlights the need for thorough investigation of kits prior to implementation.


Assuntos
Anticorpos Antivirais/isolamento & purificação , Teste Sorológico para COVID-19/instrumentação , COVID-19/diagnóstico , Imunoensaio/instrumentação , Kit de Reagentes para Diagnóstico/estatística & dados numéricos , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , COVID-19/sangue , COVID-19/imunologia , COVID-19/virologia , Teste de Ácido Nucleico para COVID-19/estatística & dados numéricos , Teste Sorológico para COVID-19/estatística & dados numéricos , Humanos , Imunoensaio/estatística & dados numéricos , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Imunoglobulina G/isolamento & purificação , Imunoglobulina M/sangue , Imunoglobulina M/imunologia , Imunoglobulina M/isolamento & purificação , Testes Imediatos/estatística & dados numéricos , RNA Viral/sangue , RNA Viral/isolamento & purificação , SARS-CoV-2/genética , SARS-CoV-2/imunologia , SARS-CoV-2/isolamento & purificação , Sensibilidade e Especificidade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...