Detailed characterization of SARS-CoV-2-specific T and B cells after infection or heterologous vaccination

• Published in: Frontiers in immunology 2023-02, Vol.14, p.1123724-1123724
• Main Authors: Lo Tartaro, Domenico, Paolini, Annamaria, Mattioli, Marco, Swatler, Julian, Neroni, Anita, Borella, Rebecca, Santacroce, Elena, Di Nella, Alessia, Gozzi, Licia, Busani, Stefano, Cuccorese, Michela, Trenti, Tommaso, Meschiari, Marianna, Guaraldi, Giovanni, Girardis, Massimo, Mussini, Cristina, Piwocka, Katarzyna, Gibellini, Lara, Cossarizza, Andrea, De Biasi, Sara
• Format: Article
• Language: English
• Subjects: antigen-specific response; B cells; B-Lymphocytes; COVID-19 - prevention & control; cytokine; Humans; Immunoglobulin G; Immunology; Interferons; Memory B Cells; polyfunctionality; SARS-CoV-2; T cells
• ISSN: 1664-3224; 1664-3224
• DOI: 10.3389/fimmu.2023.1123724

The formation of a robust long-term antigen (Ag)-specific memory, both humoral and cell-mediated, is created following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or vaccination. Here, by using polychromatic flow cytometry and complex data analyses, we deeply investigated the magnitude, phenotype, and functionality of SARS-CoV-2-specific immune memory in two groups of healthy subjects after heterologous vaccination compared to a group of subjects who recovered from SARS-CoV-2 infection. We find that coronavirus disease 2019 (COVID-19) recovered patients show different long-term immunological profiles compared to those of donors who had been vaccinated with three doses. Vaccinated individuals display a skewed T helper (Th)1 Ag-specific T cell polarization and a higher percentage of Ag-specific and activated memory B cells expressing immunoglobulin (Ig)G compared to those of patients who recovered from severe COVID-19. Different polyfunctional properties characterize the two groups: recovered individuals show higher percentages of CD4 T cells producing one or two cytokines simultaneously, while the vaccinated are distinguished by highly polyfunctional populations able to release four molecules, namely, CD107a, interferon (IFN)-γ, tumor necrosis factor (TNF), and interleukin (IL)-2. These data suggest that functional and phenotypic properties of SARS-CoV-2 adaptive immunity differ in recovered COVID-19 individuals and vaccinated ones.