Cytokines in the sera of mice immunized with VLSs, LNPs encapsulating S1 peptide or LNPs encapsulating S1 mRNA on day 28 after booster immunization. All assay values were calculated by subtracting the values detected with blank mouse serum. The data are shown as the means ± s.d. from three independent experiments ( n = 3). Significant differences were determined using one-way ANOVA with Tukey’s post hoc test.
