Fig. 4. GC B cell and T_FH cell responses induced by the pEr-P³-RBD vaccine.

The 6-week-old C57BL/6 mice were immunized by RBD (WT) antigen-only and pEr-P³-RBD (WT) on day 0 and day 21 without any adjuvant, and flow cytometry analysis of iLNs conducted on day 35. (A) GC B cells (CD19⁺CD95⁺GL7⁺), (B) class-switched (IgM⁻) within GC B cells (CD19⁺CD95⁺GL7⁺IgM⁻), (C) RBD-specific GC (CD19⁺GL7⁺CD95⁺RBD-binding⁺), and (D) T_FH cell response in iLNs on day 35; n = 8 for each group. One-way analysis of variance (ANOVA) followed by Tukey’s test was applied in (A) to (D). Differences between groups were considered significant for P values < 0.05. Error bars represent the SD of eight repeated experiments. Data are presented as mean values ± SD.