Figure 5. Impaired GC formation in CD23^crePP4^F/F mice immunized with TNP-Ficoll or infected with H1N1 virus.

(A) IHC images of PNA (dark blue) vs B220 (brown) expression in spleen sections of WT and CD23^crePP4^F/F mice (n = 3–4/group) at day 14 post-injection of PBS or TNP-Ficoll. Data in the right panels are higher magnification images of the red rectangular areas in the center panels. Red arrows indicate GCs. (B) FACS profiles of B220 vs PNA expression in total splenocytes of the mice in (A). TNP-Ficoll-immunized WT and CD23^crePP4^F/F mice (n = 3–4/group) from those in (A) that were given a second injection of TNP-Ficoll at day 100 (Re-boost). (C) Quantitation of the percentage of PNA⁺B220⁺ GC B cells among total splenocytes of the mice in (B). Data are values for individual mice, and horizontal bars are geometric means. (D) FACS profiles of CD95 vs GL7 expression by B220⁺ splenic B cells isolated from WT and CD23^crePP4^F/F mice (n = 6/group) at day 15 post-injection of PBS or H1N1 virus. (E) Quantitation of the percentage of GL7⁺CD95⁺ GC B cells among total B cells from the data in (D). (F) FACS profiles of CXCR4 vs GL7 expression by B220⁺ splenic B cells from the mice in (D). (G) Quantitation of the percentage of GL7⁺CXCR4⁺ centroblasts among total B cells from the data in (F). For (A–G), results are representative of two independent experiments.