Fig. 5.

T-cell investigation. BALB/c mice were injected with either two intramuscular doses of SARS-CoV-2 S-protein alone or one intramuscular dose of AlPO₄- or SQ@NP-adjuvanted SARS-CoV-2 S-protein. At Week 12, all mice were boosted i.m. with the same vaccine formulations. One week after the boosting vaccination, splenocyte suspensions (5 × 10⁶ cells/ml) were harvested and incubated in the absence or the presence of 1 μg/ml SARS-CoV-2 S-protein. Supernatants collected from cell cultures at Day 3 were assessed by IFN-γ, IL-5, and IL-10 ELISA. The data are presented as cytokine release in the presence of S-protein minus release in the presence of medium control and expressed as the mean ± standard deviation of triplicate cultures. *p < 0.05: Comparison with the group of protein alone. #p < 0.05: Comparison with the AlPO₄-adjuvanted protein group.