Fabrizio Cantini, Alba Grifoni, Alessandra Vergori, Fabrizio Palmieri, Elisa Petruccioli, Gilda Cuzzi, Gina Gualano, Andrea Antinori, Linda Petrone, Delia Goletti, Pietro Vittozzi, Giuseppe Ippolito, Tonino Alonzi, Luciana Lepore, Saeid Najafi Fard, Emanuele Nicastri, Enrico Girardi, Nadia Caccamo, Concetta Castilletti, Valentina Vanini, Petrone L., Petruccioli E., Vanini V., Cuzzi G., Najafi Fard S., Alonzi T., Castilletti C., Palmieri F., Gualano G., Vittozzi P., Nicastri E., Lepore L., Antinori A., Vergori A., Caccamo N., Cantini F., Girardi E., Ippolito G., Grifoni A., and Goletti D.
Objectives To examine whether specific T-cell-responses to SARS-CoV-2 peptides can be detected in COVID-19 using a whole-blood experimental setting, which may be further explored as potential diagnostic tool. Methods We evaluated IFN-γ levels after stimulating whole-blood with spike and remainder-antigens peptides megapools (MP) derived from SARS-CoV-2 sequences; IL-1β, IL-1RA, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-12p70, IL-13, IL-15, IL-17A, eotaxin, basic FGF, G-CSF, GM-CSF, IFN-γ, IP-10, MCP-1, MIP-1α, MIP-1β, PDGF, RANTES, TNF-α, VEGF were also evaluated. Results IFN-γ-response to spike and remainder-antigens MPs was significantly increased in 35 COVID-19-patients compared to 29 “NO COVID-19”-individuals (medians spike-MP: 0.26 vs 0, p=0.0002; medians remainder-antigens-MP: 0.07 vs 0.02; p=0.02). This response was detected independently of patients’ clinical parameters. IFN-γ-response to SARS-CoV-2-unrelated antigens CMV and SEB was similar in COVID-19 compared to NO-COVID-19-invididuals (median CMV: 3.46 versus 5.28, p=0.16; median SEB: 12.68 versus 15.05; p=0.1). In response to spike-MPs in COVID-19- compared to “NO COVID-19”-individuals, we found significant higher median of IL-2 (50.08 vs 0, p=0.0018), IFN-γ (90.16 vs 0, p=0.01), IL-4 (0.52 vs 0, p=0.03), IL-13 (0.84 vs 0, p=0.007) and MCP-1 (4602 vs 359.2, p=0.05). Conclusions Immune response to SARS-CoV-2 peptides in a whole-blood assay is associated to COVID-19 and it is characterized by both Th1 and Th2 profile. This experimental approach may be useful for developing new T-cell based diagnostic tests for disease and vaccine settings., Graphical abstract Image 1