COVID-19: S-Peptide RBD 484-508 Induces IFN-γ T-Cell Response in Naïve-to-Infection and Unvaccinated Subjects with Close Contact with SARS-CoV-2-Positive Patients

• Published in: Viruses Vol. 15; no. 7; p. 1417
• Main Authors: Murdocca, Michela, Citro, Gennaro, Centanini, Eleonora, Giannini, Rosalinda, Latini, Andrea, Centofanti, Federica, Piano Mortari, Eva, Cocciadiferro, Dario, Novelli, Antonio, Bernardini, Sergio, Novelli, Giuseppe, Sangiuolo, Federica
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 22.06.2023; MDPI
• Subjects: Adaptive immunity; Antibodies; Autoantibodies; Blood; Cells; Communication; COVID-19; Cytokines; Gene expression; Genetic diversity; Genomes; IFN-γ; Immune response; Infections; Lymphocytes; Lymphocytes T; Manufacturers; peptide; Peptides; pseudovirus; SARS-CoV-2; Severe acute respiratory syndrome coronavirus 2; Spike protein; Vaccine development; Vaccines; γ-Interferon; St Louis Missouri; United States > US; pseudovirus; IFN-γ; SARS-CoV-2; peptide
• ISSN: 1999-4915; 1999-4915
• DOI: 10.3390/v15071417

Despite the availability on the market of different anti-SARS-CoV-2 vaccines, there are still unanswered questions on whether they can stimulate long-lasting protection. A deep understanding of adaptive immune response to SARS-CoV-2 is important for optimizing both vaccine development and pandemic control measures. Among cytokines secreted by lymphocytes in response to viral infection, IFN-γ plays a pivotal role both in innate and adaptive immunity. In this study, we report on 28 naïve-to-SARS-Cov-2-infection and unvaccinated subjects, having reported a close and prolonged contact with COVID-19-positive patients. Samples were tested for defective genetic variants in interferon pathway genes by whole exome sequencing and anti-IFN autoantibodies production was investigated. Subject T-cells were cultured and infected with pseudotype particles bearing the S proteins and in parallel stimulated with two S-peptides designed on the RBD region of the spike protein. Our results showed that one of these peptides, RBD 484-508, induces a significant increase in IFN-γ gene expression and protein production in T-cells, comparable to those obtained in cells infected by SARS-CoV-2 pseudovirus. This work deepens our understanding of immune response and highlights the selected peptide as a reasonable approach to induce broad, potent, and variant concern-independent T-cell responses.