Interferon-gamma release assay for accurate detection of SARS-CoV-2 T cell response.
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ABSTRACT:
SUBMITTER: Murugesan K
PROVIDER: S-EPMC7665338 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundWe evaluated a standardized interferon-γ (IFN-γ) release assay (IGRA) for detection of T-cell immune response after SARS-CoV-2 infection or vaccination.MethodsThis prospective study included COVID-19 patients with different severity of illness and follow-up (FU), vaccinated subjects, and healthy unvaccinated persons. SARS-CoV-2 T-cell response was measured using a specific quantitative IGRA in whole blood (Euroimmun, Germany) and TrimericS-IgG and neutralizing antibodies with validated serological platforms. Positivity of RT-PCR or vaccination was considered as reference standard.ResultsTwo hundred and thirty nine individuals were included (152 convalescent, 54 vaccinated and 33 uninfected unvaccinated). Overall sensitivity, specificity, positive (PPV) and negative (NPV) predictive values (95% CI) of the IGRA were 81.1% (74.9%-86%), 90.9% (74.5%-97.6%), 98.2% (94.5%-99.5%), and 43.5% (31.8%-55.9%), respectively. All vaccinated SARS-CoV-2-naïve subjects had positive IGRA at 3 months. In convalescent subjects the magnitude of IFN-γ responses and IGRA accuracy varied according to disease severity and duration of FU, with the best performance in patients with severe COVID-19 at 3-month and the worst in those with mild disease at 12-month. The greatest contribution of IGRA to serological tests was observed in patients with mild disease and long-term FU (incremental difference, 30.4%).ConclusionThe IGRA assessed was a reliable method of quantifying T-cell response after SARS-COV-2 infection or vaccination. In convalescent patients the sensitivity is largely dependent on disease severity and time since primary infection. The assay is more likely to add clinical value to serology in patients with mild infections.
| S-EPMC8689778 | biostudies-literature
Project description:BackgroundAdaptive 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.MethodsAn 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).Results156 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.ConclusionSARS-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.
| S-EPMC8173205 | biostudies-literature
Project description:BackgroundHealthcare workers (HCWs) are at increased risk since they are directly exposed to SARS-CoV-2-infected patients, and nevertheless, some remain without the development of anti-SARS-CoV-2 antibodies or related symptoms, suggesting less susceptibility to the infection.MethodsThis cross-sectional, case-control study aimed to compare SARS-CoV-2 T-cell response by two different technologies, the analysis of IFN-γ+ CD8+ /CD4+ T cells by flow cytometry and the quantification of IFN-γ release by ELISA-related assay (without cell discrimination), both after SARS-CoV-2 stimulation among uninfected and convalescent HCWs.ResultsA high proportion of uninfected HCWs (53.8%) had pre-existing IFN-γ+ CD8 T-cell response after stimulation with at least one of the structural viral proteins S, M or N, while 35.9% had pre-existing IFN-γ+ CD4 T-cell response. This proportion was nearly or greater than 90% among convalescent HCWs. Interestingly, the magnitude of the response in uninfected was lower compared to that found in convalescent HCWs, using both methods. The concordance, quantifying the specific cellular response in convalescent HCWs, between both methods was 94.1% comparing CD8 T-cell response and 89.7% comparing CD4 T-cell response. This concordance was lower but still high in uninfected HCWs (76.5%) comparing CD8 T-cell response and 71.8% comparing CD4 T-cell response.ConclusionsThe good concordance between the proportion of individuals with IFN-γ release after SARS-COV-2 stimulation with the proportion of individuals with specific IFN-γ+ CD8/CD4 T cells found in this study drives IFN-γ release assays to be a simple and easy way to determine the protective immunity to SARS-CoV-2 in a wide population.
| S-EPMC8420579 | biostudies-literature
Project description:ObjectiveCharacterization of the SARS-CoV-2-specific T-cell response detected by the QuantiFERON SARS-CoV-2 RUO assay in terms of accuracy and T-cell subsets involved compared to a homemade interferon (IFN)-γ release assay (IGRA).MethodsWe evaluated T-cell response by the standardized QuantiFERON SARS-CoV-2 tubes (Ag1 and Ag2) and a homemade IGRA quantifying IFN-γ response to SARS-CoV-2 spike peptides (homemade-IGRA-SPIKE test). By flow cytometry, we evaluated the T-cell subsets mediating the specific response.ResultsWe prospectively enrolled 66 individuals: COVID-19 or post-COVID-19 subjects, and NO-COVID-19-vaccinated subjects, including healthy donors and immunocompromised subjects. The standardized kit detected 62.1% (41/66) of T-cell responders. Ag2 tube showed the higher IFN-γ quantitative and qualitative response. Ag1 tube response was mainly mediated by CD4+ T cells; Ag2 tube response was mediated by both CD4+ and CD8+ T cells. The homemade-IGRA-SPIKE test detected a higher number of responders (52/66, 78.8%) than QuantiFERON SARS-CoV-2 assay (p=0.056), and the response was found in both T-cell subsets, although a higher magnitude and response rate was observed in the CD4+ T-cell subset.ConclusionsQuantiFERON SARS-CoV-2 response is mediated by CD4+ and CD8+ T cells. A lower number of responders is found compared to homemade-IGRA-SPIKE test, likely due to the different peptide composition.
| S-EPMC9307287 | biostudies-literature
Project description:ObjectivesBlood-based Interferon-Gamma Release Assays (IGRA) identify Mycobacterium tuberculosis (MTB) sensitisation with increased specificity, but sensitivity remains impaired in human immunodeficiency virus (HIV) infected persons. The QuantiFERON-TB Gold In-Tube test contains peptide 38-55 of Rv2654c, based on data indicating differential recognition between tuberculosis patients and BCG vaccinated controls in Europe. We aimed to fine map the T cell response to Rv2654c with the view of improving sensitivity.MethodsInterferon-gamma ELISpot assay was used in HIV uninfected persons with latent and active tuberculosis to map peptide epitopes of Rv2654c. A modified IGRA was tested in two further groups of 55 HIV uninfected and 44 HIV infected persons, recruited in South Africa.ResultsThe most prominently recognised peptide was between amino acids 51-65. Using p51-65 to boost the QuantiFERON-TB Gold In-Tube assay, the quantitative performance of the modified IGRA increased from 1.83 IU/ml (IQR 0.30-7.35) to 2.83 (IQR 0.28-12.2; p = 0.002) in the HIV uninfected group. In the HIV infected cohort the percentage of positive responders increased from 57% to 64% but only after 3 months of ART (p = ns).ConclusionsOur data shows the potential to population tailor detection of MTB sensitization using specific synthetic peptides and interferon-gamma release in vitro.
| S-EPMC4747975 | biostudies-literature
Project description:The humoral immune response to SARS-CoV-2 results in antibodies against spike (S) and nucleoprotein (N). However, whilst there are widely-available neutralization assays for S-antibodies, there is no assay for N-antibody activity. Here we present a simple in vitro method called EDNA (electroporated-antibody dependent neutralization assay) that provides a quantitative measure of N-antibody activity in unpurified serum from SARS-CoV-2 convalescents. We show that N-antibodies neutralize SARS-CoV-2 intracellularly and cell-autonomously but require the cytosolic Fc-receptor TRIM21. Using EDNA, we show that low N-antibody titres can be neutralizing, whilst some convalescents possess serum with high titres but weak activity. N-antibody and N-specific T cell activity correlates within individuals, suggesting N-antibodies may protect against SARS-CoV-2 by promoting antigen presentation. This work highlights the potential benefits of N-based vaccines and provides an in vitro assay to allow the antibodies they induce to be tested.
| S-SCDT-EMBOJ-2021-108588 | biostudies-other
Project description:Tuberculosis is caused by mycobacterium, a potentially fatal infectious bacterium. In recent years, TB cases increased in the whole world. WHO statistics data shows that the world's annual tuberculosis incidence was 8~10 million with about 3 million deaths. Several studies have shown that susceptibility to tuberculosis may be associated with IFNGR1 gene polymorphisms. Here, we report the distribution frequency of IFNGR1 gene polymorphisms in 103 cases of IGA-negative patients and 100 cases of IGA-positive patients from China by sequencing the IFNGR1 proximal ~750 bp promoter region. We found a total of 5 types of site mutations: -611 (G/A), -56 (T/C), -255 (C/T), -359 (T/C), and -72 (C/T). The two main types of gene polymorphisms among the IGA-negative and IGA-positive groups were -611 (G/A), with mutation rates of 88.3% and 78.4%, respectively, and -56 (T/C), with mutation rates of 84.5% and 83.8%, respectively, which had no statistical significance, and there was no correlation with the incidence of tuberculosis.
| S-EPMC5676416 | biostudies-literature
Project description: Not available
| S-EPMC8426863 | biostudies-literature
Project description:Identification and treatment of latent tuberculosis infection (LTBI) can substantially reduce the risk of developing active disease. However, there is no diagnostic gold standard for LTBI. Two tests are available for identification of LTBI: the tuberculin skin test (TST) and the gamma interferon (IFN-γ) release assay (IGRA). Evidence suggests that both TST and IGRA are acceptable but imperfect tests. They represent indirect markers of Mycobacterium tuberculosis exposure and indicate a cellular immune response to M. tuberculosis. Neither test can accurately differentiate between LTBI and active TB, distinguish reactivation from reinfection, or resolve the various stages within the spectrum of M. tuberculosis infection. Both TST and IGRA have reduced sensitivity in immunocompromised patients and have low predictive value for progression to active TB. To maximize the positive predictive value of existing tests, LTBI screening should be reserved for those who are at sufficiently high risk of progressing to disease. Such high-risk individuals may be identifiable by using multivariable risk prediction models that incorporate test results with risk factors and using serial testing to resolve underlying phenotypes. In the longer term, basic research is necessary to identify highly predictive biomarkers.
| S-EPMC3910908 | biostudies-other
Project description:Measurements of serum-neutralizing antibody and anti-rotavirus immunoglobulin A (IgA) are the current standard for assessing immune responses following rotavirus vaccination. However, there is ongoing debate as to whether antibody titers correlate with protection against rotavirus gastroenteritis. Children recovering from rotavirus gastroenteritis have increased gamma interferon release from cultured peripheral blood mononuclear cells (PBMCs), suggesting that cell-mediated immunity (CMI) may play a role in viral clearance and protection from subsequent gastroenteritis. We have developed a gamma interferon enzyme-linked immunospot (ELISPOT) assay for evaluation of CMI responses to rotavirus using frozen PBMCs obtained from healthy adults. Responses to three different rotavirus antigen types were analyzed-a peptide pool based on the human VP6 sequence; reassortant human:bovine vaccine strains; and cell culture-adapted (CCA) human G1, G2, G3, G4, and bovine (WC3) G6 strains. The reassortant strains consist of a bovine WC3 genome background expressing the human rotavirus surface proteins VP7 (G1, G2, G3, or G4) or VP4 (P1). Responses to titrations of the peptide pool as well as CCA and reassortant strains were assessed. Gamma interferon ELISPOT responses were similar for CCA and reassortant strains, whether live or UV inactivated, and when tested either individually or pooled. For most subjects, responses to the VP6 peptide pool positively correlated with responses to CCA and reassortant strains. Cell depletion studies indicate the memory responses detected with these frozen adult PBMCs were primarily due to the CD4+ T-cell population. This gamma interferon ELISPOT assay provides a new tool to apply in clinical studies for the characterization of natural or vaccine-induced CMI to rotavirus.
| S-EPMC1082727 | biostudies-literature