AUTHOR=Saresella Marina , Piancone Federica , Marventano Ivana , Hernis Ambra , Trabattoni Daria , Invernizzi Mattia , La Rosa Francesca , Clerici Mario 

TITLE=Innate immune responses to three doses of the BNT162b2 mRNA SARS-CoV-2 vaccine

JOURNAL=Frontiers in Immunology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2022.947320

DOI=10.3389/fimmu.2022.947320

ISSN=1664-3224

ABSTRACT=<p>To explore the effects of SARS-CoV-2-mRNA vaccines on innate immune responses we enrolled 58 individuals who received 3 doses of the BNT162b2 vaccine in a longitudinal study; 45 of these individuals had never been SARS-CoV-2 infected. Results showed that vaccination significantly increased: 1) classical and intermediate inflammatory monocytes, 2) CD56<sup>bright</sup>, CD56<sup>dim</sup>, and CD56<sup>dim</sup>/CD16<sup>dim</sup> NK cells, and 3) IFN-γ+ ;production as well as perforin and granzyme content by NK cells. Vaccination also reduced expression of the NK inhibitory receptor ILT-2, increasing that of the stimulatory molecule 2DS2. These effects were long-lasting and were boosted by every vaccine dose. Notably, ILT-2 expressing NK cells were reduced even more robustly in COVID-19-recovereed vaccines. BNT162b1 mRNA vaccine is known to induce potent adaptive immune responses; results herein show its ability to modulate innate immune responses as well, offering further support to the indication to proceed with worldwide vaccination efforts to end the SARS-CoV-2 pandemic.</p>