Fig. 5.

Specific humoral and T cell response of mice immunized with Sad23L-nCoV-S and Sad23L-nCoV-S-CaP vaccine by prime-boost regimen. A Immunization regimen. (B) S1-BAb or (C) S2-BAb titers were tested by ELISA. D NAb titers were measured by pVNT (IC₅₀). E IFN-γ secreting level to S peptides was measured by ELISpot. (F–I) Frequency of intracellular IFN-γ, TNF-α and IL-2 expressing CD4⁺ or CD8⁺ T cell response to S peptides was determined by intracellular cytokine staining, respectively. Data are shown as mean ± SEM. P values are calculated with two-tailed t test. Statistically significant differences are shown with asterisks (*, P < 0.05; **, P < 0.01; ***, P < 0.001; ns, P > 0.05 or no significant difference).