AUTHOR=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 TITLE=Detailed characterization of SARS-CoV-2-specific T and B cells after infection or heterologous vaccination JOURNAL=Frontiers in Immunology VOLUME=14 YEAR=2023 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2023.1123724 DOI=10.3389/fimmu.2023.1123724 ISSN=1664-3224 ABSTRACT=

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.