Fig. 6: SPION-based nanovaccines promote lymph node retention, DC uptake, and interactions with macrophages.

a Schedule for one-dose subcutaneous injection of C57BL/6 mice. b Representative photographs of draining lymph nodes excised 20 h after vaccination with indicated preparations, separately merged with fluorescence signals from the nanovaccines formulated with TAMARA-labeled p210 or Quasar 670-labeled CpG ODNs (n = 3 individual experiments). c Prussian blue staining of sectioned brachial lymph nodes (BLN) and inguinal lymph nodes (ILN) excised at 20 h post vaccination (n = 3 individual experiments). d Flow cytometric analyses of FITC-labeled p210 in DC cells (CD11c⁺) from draining lymph nodes of mice treated with the indicated preparations. The data are presented as mean ± SD (n = 3 mice per group). Statistical significance was calculated via one-way ANOVA with Dunnett’s post hoc test versus the D + P group. Statistical significant p values were reported; ns means no significance. e Representative images of lymph nodes from C57BL/6 mice treated with one dose of Quasar 670-labeled CpG-ODNs (purple) and TAMRA-labeled p210 (red) nanovaccines. DCs and macrophages were immunofluorescently stained for CD11c and CD68, respectively (green). Nuclei were counterstained with DAPI (blue). White arrows in the representative images indicate co-localization between or close contact of the vaccines and DCs or macrophages. n = 3 individual experiments in each treatment group. Source data are provided as a Source Data file.