Fig. 5: T cell recognition to target cells expressing N protein and inhibition of SARS-CoV-2 viral replication by HLA-C12-restricted T-cell lines from convalescents.

a–c HLA-C12-positive T-cell lines of convalescent donors (Supplementary Fig. 4a and b) were stimulated with A549-ACE/C1202 (Supplementary Fig. 4c) expressing Nucleocapsid protein derived from prototype. The level of IFN-γ production of KF9-specific T cells in stimulation with the KF9 peptide (a, Supplementary Fig. 4d) and N-expressing target cells (b, Supplementary Fig. 4h) in three vaccinated donors and the level of CD107a in response to those (c, Supplementary Fig. 4i) in three convalescent donors. b, c A statistically significant difference is determined by Wilcoxon matched-pairs signed rank test (**p = 0.0078; versus mock). d, e Inhibition of viral replication of prototype, Omicron BA.1, BA.2 and BA.5 by KF9-specific T cells compared to that by SARS-CoV-2 S-derived QI9-specific T cells in two donors (d) and that of prototype by KF9-specific T cells in six donors and QI9-specific T cells in five donors (e) are shown. See Supplementary Fig. 4j (T cell lines tested in this assay), Supplementary Fig. 5c (Viral replication of the prototype and variants) and Supplementary Fig. 5d (Inhibition of viral replication of Omicron BA.1, BA.2 and BA.5 by KF9- and QI9-specific T cells). e A statistically significant difference is determined by unpaired Mann–Whitney t-test (**p = 0.0043; versus QI9-specific T cells). a, b The assay was performed in triplicate, and the means are shown with the SD. c The assay was performed in triplicate, and the median is shown. d, e Assay was performed in triplicate or quadruplicate, and the means are shown with the SD (d), and data are expressed as median (e).