Elsevier

Biosafety and Health

Volume 4, Issue 3, June 2022, Pages 179-185
Biosafety and Health

An adjusted ELISpot-based immunoassay for evaluation of SARS-CoV-2-specific T-cell responses

https://doi.org/10.1016/j.bsheal.2022.04.005Get rights and content
Under a Creative Commons license
open access

Highlights

  • Scientific question: This study proposed and evaluated a modified SARS-CoV-2-specific immunoassay with high validity.

  • Evidence before this study: The number of confirmed COVID-19 cases is increasing globally. Compared with humoral immunity, the evaluation of SARS-CoV-2-specific cellular immunity has not been completely unified and standardized, and has the characteristics of complex operation and high requirements of equipment.

  • New findings: An assessment of the SARS-CoV-2-specific T-cell responses of COVID-19 convalescents and healthy individuals was conducted through an adjusted ELISpot-based immunoassay in this study. The data showed that the parallel combination test and serial combination test of SARS-CoV-2 peptide pools showed higher sensitivity and specificity, respectively. The combined detection of peptide pools could obtain higher detection efficiency, especially the serial test, whose Youden indices were generally better than that of the parallel test. Combination of M and N peptide pool serial evaluation is optimal.

  • Significance of the study: The SARS-CoV-2-specific T-cell immunoassay proposed in this study is practical and valid, which is conducive to promote the standardized assessment of immune responses to SARS-CoV-2 variants, vaccines and diagnosis.

Abstract

Like antibody evaluation, using an effective antigen-specific T-cell immunity assessment method in coronavirus disease 2019 (COVID-19) patients, survivors and vaccinees is crucial for understanding the immune persistence, prognosis assessment, and vaccine development for COVID-19. This study evaluated an empirically adjusted enzyme-linked immunospot assay for detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific T-cell immunity in 175 peripheral blood samples from COVID-19 convalescents and healthy individuals. Results of viral nucleic acid were used as the gold standard of infection confirmation. The SARS-CoV-2M peptide pool had higher sensitivity of 85% and specificity of 71% for the single peptide pool. For combined peptide pools, the parallel evaluation (at least one of the peptide pools is positive) of total peptide pools (S1&S2&M&N) had higher sensitivity (up to 93%), and the serial evaluation (all peptide pools are positive) of total peptide pools had higher specificity (up to 100%). The result of the serial evaluation was better than that of the parallel evaluation as a whole. The detection efficiency of M and N peptide pool serial evaluation appeared the highest, with a sensitivity of 80% and specificity of 93%. This T-cell immunity detection assay introduced in this report can achieve high operability and applicability. Therefore, it can be an effective SARS-CoV-2-specific cellular immune function evaluation method.

Keywords

SARS-CoV-2
COVID-19
T-cell response
ELISpot assay
Sensitivity
Specificity

Cited by (0)

1

These authors contributed equally to this manuscript.

2

Given their roles as Editorial Board Members, William J. Liu and Guizhen Wu had no involvement in the peer-review of this article and had no access to information regarding its peer-review. Full responsibility for the editorial process for this article was delegated to the Editor Jianwei Wang.