Performance of an interferon-γ release assay-based test for cell-mediated immunity to SARS-CoV-2

Front Immunol. 2023 Feb 16:14:1069968. doi: 10.3389/fimmu.2023.1069968. eCollection 2023.

Abstract

In search for immunological correlates of protection against acute coronavirus disease 2019 (COVID-19) there is a need for high through-put assays for cell-mediated immunity (CMI) to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We established an interferon-γ release assay -based test for detection of CMI against SARS-CoV-2 spike (S) or nucleocapsid (NC) peptides. Blood samples obtained from 549 healthy or convalescent individuals were measured for interferon-γ (IFN-γ) production after peptide stimulation using a certified chemiluminescence immunoassay. Test performance was calculated applying cutoff values with the highest Youden indices in receiver-operating-characteristics curve analysis and compared to a commercially available serologic test. Potential confounders and clinical correlates were assessed for all test systems. 522 samples obtained from 378 convalescent in median 298 days after PCR-confirmed SARS-CoV-2 infection and 144 healthy control individuals were included in the final analysis. CMI testing had a sensitivity and specificity of up to 89% and 74% for S peptides and 89% and 91% for NC peptides, respectively. High white blood cell counts correlated negatively with IFN-γ responses but there was no CMI decay in samples obtained up to one year after recovery. Severe clinical symptoms at time of acute infection were associated with higher measures of adaptive immunity and reported hair loss at time of examination. This laboratory-developed test for CMI to SARS-CoV-2 NC peptides exhibits excellent test performance, is suitable for high through-put routine diagnostics, and should be evaluated for clinical outcome prediction in prospective pathogen re-exposure.

Keywords: COVID-19; QuantiFERON; SARS-CoV-2; T cell; coronavirus; interferon; interferon gamma release assay.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • COVID-19*
  • Humans
  • Immunity, Cellular
  • Interferon-gamma Release Tests
  • Prospective Studies
  • SARS-CoV-2*

Grants and funding

This work was supported by the Deutsche Forschungsgemeinschaft (STA 1549/2-1 and STA 1549/1-2) and the Stiftung für Pathobiochemie und Molekulare Diagnostik (German Society of Clinical Chemistry and Laboratory Medicine) to FRS. We acknowledge financial support from the Open Access Publication Fund of UKE - Universitätsklinikum Hamburg-Eppendorf- and DFG – German Research Foundation. The underlying Post-COVID project was specifically supported by Senat und Behörde für Wissenschaft, Forschung, Gleichstellung und Bezirke (BWFGB) [Reference E43026-03.HCHS]; Hamburg and the Deutsche Forschungsgemeinschaft [Grant Number TH1106/5-1; AA93/2-1]. The HCHS is generally funded by the euCanSHare grant agreement [Grant Number 825903-euCanSHare H2020]; the Foundation Leducq [Grant Number 16 CVD 03] and the Innovative medicine initiative [Grant Number 116074]. The HCHS is additionally supported by the Deutsche Gesetzliche Unfallversicherung (DGUV); Deutsches Krebsforschungszentrum (DKFZ); Deutsches Zentrum für Herz-Kreislauf-Forschung (DZHK); Deutsche Stiftung für Herzforschung; Seefried Stiftung; Amgen; Bayer; Novartis; Schiller; Siemens; Topcon, and Unilever. The study is further supported by donations from the “Förderverein zur Förderung der HCHS e.V.”, and TePe® (2014). The funders were not involved in the study design, collection, analysis, interpretation of data, the writing of this article, or the decision to submit it for publication.