BNT162b2 vaccine induces antibody release in saliva: a possible role for mucosal viral protection?
Abbass Darwich, Chiara Pozzi, Giulia Fornasa, Michela Lizier, Elena Azzolini, Ilaria Spadoni, Francesco Carli, Antonio Voza, Antonio Desai, C. A. Ferrero, Luca Germagnoli, ICH COVID‐19 Task‐force, Alberto Mantovani, María Rescigno, Alessio Aghemo, Anfray Clement, Salvatore Badalamenti, Cristina Belgiovine, Alice Bertocchi, Sara Bombace, Paola Brescia, Francesca Calcaterra, Michela Calvi, Cancellara Assunta, Arianna Capucetti, Carenza Claudia, Sara Carloni, Silvia Carnevale, Valentina Cazzetta, Cecconi Maurizio, Michele Ciccarelli, Coianiz Nicolò, Abbass Darwich, Ana Lleo De Nalda, De Paoli Federica, Di Donato Rachele, Digifico Elisabeth, Barbara Durante, Farina Floriana Maria, Valentina Ferrari, Giulia Fornasa, Franzese Sara, Gil Gomez Antonio, Silvia Giugliano, Ana Rita Gomes, Michela Lizier, Lo Cascio Antonino, Alessia Melacarne, Alessandro M. Mozzarelli, Ilaria My, Bianca Oresta, Fabio Pasqualini, Anna Pastò, Pelamatti Erica, Chiara Perucchini, Pozzi Chiara, Valeria Rimoldi, Rimoldi Monica, Scarpa Alice, Selmi Carlo, Alessandra Silvestri, Sironi Marina, Ilaria Spadoni, Salvatore Spanò, Gianmarco Spata, Domenico Supino, Tentorio Paolo, Aldo Ummarino, Sonia Valentino, Voza Antonio, Elisa Zaghi, Veronica Zanon
Abstract
Vaccination against an airborne pathogen is very effective if it induces also the development of mucosal antibodies that can protect against infection. The mRNA-based vaccine-encoding SARS-CoV-2 full-length spike protein (BNT162b2, Pfizer/BioNTech) protects also against infection despite being administered systemically. Here, we show that upon vaccination, cognate IgG molecules are also found in the saliva and are more abundant in SARS-CoV-2 previously exposed subjects, paralleling the development of plasma IgG. The antibodies titer declines at 3 months from vaccination. We identified a concentration of specific IgG in the plasma above which the relevant IgG can be detected in the saliva. Regarding IgA antibodies, we found only protease-susceptible IgA1 antibodies in plasma while they were present at very low levels in the saliva over the course of vaccination of SARS-CoV-2-naïve subjects. Thus, in response to BNT162b2 vaccine, plasma IgG can permeate into mucosal sites and participate in viral protection. It is not clear why IgA1 are detected in low amount, they may be proteolytically cleaved.