A SARS-CoV-2 Spike Receptor Binding Motif Peptide Induces Anti-Spike Antibodies in Mice andIs Recognized by COVID-19 Patients

• Published in: Frontiers in immunology 2022-05, Vol.13, p.879946-879946
• Main Authors: Pratesi, Federico, Errante, Fosca, Pacini, Lorenzo, Peña-Moreno, Irina Charlot, Quiceno, Sebastian, Carotenuto, Alfonso, Balam, Saidou, Konaté, Drissa, Diakité, Mahamadou M, Arévalo-Herrera, Myriam, Kajava, Andrey V, Rovero, Paolo, Corradin, Giampietro, Migliorini, Paola, Papini, Anna M, Herrera, Sócrates
• Format: Article
• Language: English
• Subjects: Animals; Antibodies, Viral; COVID-19; Emerging diseases; Human health and pathology; Humans; immunized animals; Immunology; Infectious diseases; Life Sciences; Mice; neutralizing Abs; Peptides; receptor binding motif; SARS-CoV-2; spike (S) protein; Spike Glycoprotein, Coronavirus
• ISSN: 1664-3224; 1664-3224
• DOI: 10.3389/fimmu.2022.879946

The currently devastating pandemic of severe acute respiratory syndrome known as coronavirus disease 2019 or COVID-19 is caused by the coronavirus SARS-CoV-2. Both the virus and the disease have been extensively studied worldwide. A trimeric spike (S) protein expressed on the virus outer bilayer leaflet has been identified as a ligand that allows the virus to penetrate human host cells and cause infection. Its receptor-binding domain (RBD) interacts with the angiotensin-converting enzyme 2 (ACE2), the host-cell viral receptor, and is, therefore, the subject of intense research for the development of virus control means, particularly vaccines. In this work, we search for smaller fragments of the S protein able to elicit virus-neutralizing antibodies, suitable for production by peptide synthesis technology. Based on the analysis of available data, we selected a 72 aa long receptor binding motif (RBM ) of RBD. We used ELISA to study the antibody response to each of the three antigens (S protein, its RBD domain and the RBM synthetic peptide) in humans exposed to the infection and in immunized mice. The seroreactivity analysis showed that anti-RBM antibodies are produced in COVID-19 patients and immunized mice and may exert neutralizing function, although with a frequency lower than anti-S and -RBD. These results provide a basis for further studies towards the development of vaccines or treatments focused on specific regions of the S virus protein, which can benefit from the absence of folding problems, conformational constraints and other advantages of the peptide synthesis production.