GC formation following T-dependent immunization. SWAP-70^+/+ and SWAP-70^−/− mice were immunized with CFA or NP-KLH emulsified in CFA. (A) Fourteen days after NP-KLH immunization or CFA injection, spleen sections stained for PNA (green) and B220 (red). Data are representative of 3 independent experiments. (B) Percentage of B follicles containing GC in spleen sections of immunized animals. (C) Flow cytometry of NP-specific B cells in the spleen of SWAP-70^+/+ or SWAP-70^−/− mice 14 days after immunization. (D) Mean percentage of NP⁺B220⁺ B cells in spleen of immunized mice at the indicated time. Experiments were done 5 times. (E) Flow cytometry of GL7 expression in NP⁺B220⁺ in spleen at the indicated time. (F) Flow cytometry of BrdU in NP⁺B220⁺ cells in spleen 14 days after immunization. Numbers indicate percentage of cells. Data are representative of 2 independent experiments. (G) Spleen stained for B220 (blue) PNA (red) and NP (green) 14 days after immunization. All scale bars represent 200 μm.