Memory B-cell response is reduced in SWAP-70^−/− mice. Mice were immunized with NP-KLH emulsified in CFA, rested for 85 days, and reimmunized with NP-KLH for 5 days. (A) Flow cytometry of NP⁺ B cells in spleen. (B) Percentage of CD138⁺B220^low, B220^high, and B220⁻CD138⁺ cells among the NP⁺ cells in the spleen. (C) Flow cytometry of NP⁺ B cells in BM. (D) Percentage of CD138⁺B220^low, B220^high, and B220⁻ cells among the NP⁺ cells in the BM. Data represent the mean percentage of cells in 3 independent experiments. (E) Flow cytometry of total plasma cells CD138⁺B220^low in the spleen. Numbers indicate the percentage among total lymphocytes. (F) NP-specific total (left panel) and high-affinity (right panel) anti-IgG1 titers were determined by ELISA with NP₁₂-BSA and NP₃-BSA as capture antigen. Black and white circles represent individual mouse for wt and SWAP-70^−/− respectively. Black and gray bars represent the mean average for wt and SWAP-70^−/−, respectively. Values are expressed as arbitrary optical-density units at 405 nm. Fold increase in NP-IgG1 titers between no boost and after boost (low panels). (G) ELISPOT analysis of total (left panel) and high-affinity (right panel) IgG1 secretion by splenocytes from wt and SWAP-70^−/− mice. Data represent the mean number of spots.