Fig. 7: Immunogenicity of ICO scaffold and biosafety of ICO-RBD nanovaccines.

a Percentages of CD80⁺CD86⁺ in CD11C⁺ cells in BMDCs after treatment with different concentrations of ICO for 12 h, as detected using flow cytometry (n = 3 independent experiments). b Percentages of CD80⁺CD86⁺ in CD11C⁺ DCs in the inguinal lymph nodes, as detected using flow cytometry (n = 8 mice). Mice were intramuscularly injected with two doses of ICO at week 0 and 3, and the inguinal lymph nodes were harvested after 3 weeks. c Schematic illustration of the vaccination schedule. Mice were randomly divided into 3 groups: PBS (control), ICO-RBD nanovaccines without AddaVax (ICO-RBD without AddaVax), and ICO-RBD nanovaccines with AddaVax (ICO-RBD vaccines). Mice were intramuscularly immunized with two doses of ICO-RBD nanovaccines at week 0 and 3, mixed with or without 50 μL AddaVax. d RBD-specific IgG titers in serum, measured at week 2 and 5 by ELISA (n = 8 mice). Blood biochemical analysis (e, n = 7 mice) at day 22 and histological evaluation of major organs (f) at week 5. These experiments (f) were repeated three times independently with similar results. Black scale bar, 50 μm, white scale bar, 100 μm. Mice were intramuscularly immunized with two doses of ICO-RBD nanovaccines at week 0 and 3, mixed with 50 μL AddaVax. The data were processed on GraphPad Prism 8. The data are presented as the mean ± SEM in panel d, and the mean ± SD in panel a, b and e. Statistical significance (P value) was calculated by one-way ANOVA followed by Tukey’s test in panels a and d, and a two-tailed unpaired t test in panels b and e. *P < 0.05; ***P < 0.001. ns, P > 0.05, no significant difference. Source data are provided as a Source Data file.