Fig. 5: Immunization with NDV and MVA viral vectors encoding SARS-CoV-2 S protein elicit pulmonary SARS-CoV-2-specific T-cell responses in K18-hACE2 transgenic mice challenged with SARS-CoV-2.

Pulmonary SARS-CoV-2 S-specific T-cell responses, directed against S peptide pools, were analysed in lung cells obtained at day 17 post-challenge, and evaluated by ICS, as described in Materials and Methods. A Magnitude of mucosal S-specific CD8⁺ T-cell responses in lung cells. Percentages of CD8⁺ T cells expressing CD107a and/or producing IFNγ and/or TNFα and/or IL-2. P values were determined as described in Materials and Methods using an approach that corrects measurements for the medium response, calculating confidence intervals (**p < 0.002; ***p < 0.001). B Polyfunctional profile (based on expression of selected markers CD107a, IFNγ, TNFα, and IL-2) of total mucosal S-specific CD8⁺ T-cell responses in lung cells. The response profiles are shown on the x axis, and the percentages of CD8⁺ T cells for each of the vaccination groups are shown on the y axis. The pie charts summarize the percentage of S-specific CD8⁺ T cells exhibiting one, two, three, or four markers, which are shown color coded. C Memory phenotypic profiles of the mucosal S-specific CD8⁺ T cells. Percentages of naive (CD127⁻/CD62L⁺), T central memory (Tcm; CD127⁺/CD62L⁺), T effector memory (Tem; CD127⁺/CD62L⁻), and T effector (Te; CD127⁻/CD62L⁻) CD8⁺ T cells expressing CD107a, and/or secreting IFN-γ, TNF-α, and IL-2 in response to stimulation with S peptide pools.