SARS-CoV-2 specific T-cell humoral response assessment after COVID-19 vaccination using a rapid direct real-time PCR amplification

• Published in: Clinical chemistry and laboratory medicine Vol. 61; no. 9; pp. 1652 - 1660
• Main Authors: Cosma, Chiara, Galla, Luisa, Padoan, Andrea, Furlan, Giulia, Marchioro, Lucio, Zaninotto, Martina, Basso, Daniela, Plebani, Mario
• Format: Journal Article
• Language: English
• Published: Germany De Gruyter 28.08.2023; Walter De Gruyter & Company
• Subjects: Alzheimer's disease; Amyloid precursor protein; Antibodies, Viral; Assaying; Cell-mediated immunity; cellular immunity; COVID-19; COVID-19 - diagnosis; COVID-19 - prevention & control; COVID-19 Testing; COVID-19 Vaccines; CXCL10 protein; direct real-time PCR amplification; Enzyme-linked immunosorbent assay; Gene expression; Homology; Humans; Humoral immunity; Immune response; Immune response (humoral); Immune system; Immunoglobulin G; Immunoreactivity; interferon gamma release assay; Lithium; Lymphocytes; Lymphocytes T; Measurement methods; Medical personnel; Peptides; Polymerase chain reaction; Qualitative analysis; Real time; Real-Time Polymerase Chain Reaction; SARS-CoV-2; SARS-CoV-2 specific T cell; Severe acute respiratory syndrome coronavirus 2; T-Lymphocytes; Transplantation; Vaccination; γ-Interferon; COVID-19; humoral immunity; SARS-CoV-2 specific T cell; interferon gamma release assay; cellular immunity; direct real-time PCR amplification
• ISSN: 1434-6621; 1437-4331; 1437-4331
• DOI: 10.1515/cclm-2023-0129

The SARS-CoV-2 immune response is mediated by both humoral and cellular immunity. In this study, SARS-CoV-2 specific cellular immunity was tested by a novel direct real-time PCR (dRT-PCR) assay, targeting mRNA of , and compared with respect to an ELISA measuring interferon gamma (IFN-γ) release. Whole blood (Li-He) and serum samples were collected from 92 healthcare workers (HCW), with three doses of homologous (Pfizer/BioNTech, n=74) or heterologous (Pfizer/BioNTech and Vaxzevria or Moderna, n=18) vaccinations. Li-He samples were incubated with SCV2 PANEL-1-T-ACTIVATION (Hyris srl, Lodi, Italy), or CoV-2 IGRA TUBE ELISA (Euroimmune, Lubeck, Germany). mRNA expression was analyzed by bCube/bApp (Hyris), while IFN-γ was evaluated by quant-T-Cell SARS-CoV-2 ELISA (Euroimmune). Anti-SARS-CoV-2 S-RBD IgG levels were measured in sera using a CLIA assay (Snibe, Shenzen, China). Imprecision of dRT-PCR assay was found to be satisfactory, and the two methods for measuring T cell immunity to SARS-CoV-2 peptides agreed in 82/87 (94.2%) of results. At qualitative dRT-PCR analyses, 81 subjects (93.2%) resulted as reactive to SARS-CoV-2 peptides, 3 (3.4%) were borderline and 3 were negative (3.4%). At univariate and multivariate analyses of quantitative dRT-PCR mRNA of and IFN-γ release results showed no difference between HCW with previous infection, homologous/heterologous vaccination, or demographical features. Anti-SARS-CoV-2 S-RBD IgG was associated with the previous infection and the time between the last vaccination or positivity. Direct RT-PCR appeared accurate for determining the presence or absence of immunoreactivity of SARS-CoV-2 specific T cells, especially when rapid analyses are required, such as for organ transplantation.