Fig. 2

RBD-PP targets lymph nodes and enhances antigen processing. A Twelve hours after the subcutaneous injection of 10 µg Cy7-labeled samples for each group, the heart (H), liver (Li), spleen (S), lung (Lu), kidney (K) and inguinal lymph nodes (LN) were collected and observed by live imaging. B The fold change of the fluorescence intensity relative to that in the free Cy7 control group (n = 3). C BMDC uptake. Representative images with green representing the antigen RBD, red representing CD11c, and blue representing DAPI-stained nuclei. D Twelve hours after the subcutaneous injection of 10 µg Cy7-labeled samples for each group, flow cytometry analysis of representative graphs of Cy7⁺CD11c⁺MHC-II⁺, (E) CD80⁺CD11c⁺MHC-II⁺, and (F) CD86⁺ CD11c⁺MHC-II⁺ cells in lymph nodes (n = 3). G Ten days after mice were immunized with 50 µg of different vaccines, the percentages of T follicular helper (Tfh) cells (CD3⁺CD4⁺CXCR5⁺PD-1⁺) and (H) germinal center (GC) B cells (CD19⁺B220⁺CD95⁺GL7⁺) in lymph nodes were measured by flow cytometry (n = 3). Data are shown as the mean ± SD. Statistical significance was calculated via one-way ANOVA (B, D-H) to obtain p values: ****p < 0.0001, ***p < 0.001, **p < 0.01, and *p < 0.05