Memory T Cells Subpopulations in a Cohort of COVID-19 Vaccinated or Recovered Subjects

• Published in: Viral immunology Vol. 37; no. 9; p. 440
• Main Authors: Iuliano, Marco, Mongiovì, Roberta Maria, Parente, Alberico, Grimaldi, Lorenzo, Kertusha, Blerta, Carraro, Anna, Marocco, Raffaella, Mancarella, Giulia, Del Borgo, Cosmo, Dorrucci, Maria, Lichtner, Miriam, Mangino, Giorgio, Romeo, Giovanna
• Format: Journal Article
• Language: English
• Published: United States 01.11.2024
• Subjects: Adult; Aged; CD4-Positive T-Lymphocytes - immunology; CD8-Positive T-Lymphocytes - immunology; Cohort Studies; COVID-19 - immunology; COVID-19 - prevention & control; COVID-19 Vaccines - immunology; Epitopes, T-Lymphocyte - immunology; Female; Humans; Immunodominant Epitopes - immunology; Immunologic Memory; Male; Memory T Cells - immunology; Middle Aged; SARS-CoV-2 - immunology; Spike Glycoprotein, Coronavirus - immunology; T-Lymphocyte Subsets - immunology; Vaccination; SARS-CoV-2; vaccine; memory T cells
• ISSN: 1557-8976
• DOI: 10.1089/vim.2024.0065

Following viral infection, antigen-restricted T lymphocytes are activated and recognize infected cells to eliminate them. A subset of T cells differentiates into memory lymphocytes able to counteract viral rechallenge in a faster and enhanced way. SARS-CoV-2 can escape immune responses leading to a poor clinical outcome. Immune escape can be associated with the failure of the development of T cell memory compartments. The aim of this study is to characterize the T memory subsets and to test the immune response against class I- and II-restricted immunodominant epitopes shared by ancestral and SARS-CoV-2 variants strains. T memory subsets and recognition of SARS-CoV-2S Spike-specific epitopes were analyzed by flow cytometry on 14 fully vaccinated healthy donors (HDV) and 18 COVID-19 recovered patients (CD). The results obtained showed that CD8+ T naïve subset numbers decreased in association with a significant increase of the effector memory T cell subset whereas there was a small increase in the percentage of SARS-CoV-2 antigen-restricted T clones in both CD4 and CD8+ subset in the CD compared to HDV sample. Collectively, these features may reflect a broader cytotoxic T cell repertoire stimulated by the virus during the natural infection compared to the spike-restricted response activated during vaccination.