Figure 4.

AP205-RBD induced a prolonged GC response

(A and B) Splenocytes from naive mice or mice immunized with AP205-RBD previously were examined for antigen-specific cells by RBD-BV650 or AP205-AF647 labeling. RBD-BV650⁺ and AP205-AF647⁺ cells are defined as antigen⁺ cells for simplicity, although they may consist of a fraction of fluorophore-specific cells, which are IgD⁺IgM⁺ (Figures S4A and S4B). Antigen-specific plasma cells (PCs) (CD19^–B220^–IRF4⁺), germinal center (GC) B cells (CD19⁺B220⁺GL7⁺CD38^–), and Ig-switched memory B cells (swIg MemB) (GL7^–CD38⁺IgD^–IgM^–) can be found in AP205-RBD-immunized animals. The percentages of the antigen⁺ cells in the total splenocytes and the percentages of the indicated subsets within the total antigen⁺ cells are labeled in red. The percentages of the gated cells within the parental group of cells are labeled in black. Representative data are shown in (A), and the summary data are shown in (B). Symbols indicate data of individual mice. Bars indicate the geometric mean of each group.

(C and D) Spleen sections were stained for GC structures with IgD (brown) and GL-7 (pink) by immunohistochemistry. Representative data are shown in (C), and quantification data are shown in (D). Symbols indicate data collected from individual mice, and bars indicate the mean of each group.

See also Figure S4.