B cell response to T-dependent immunogens is intact in CD25 KO mice. (A–C) Mice were immunized with 100 µg of NP-CGG intraperitoneally, boosted on day 7 and analyzed on day 10. (A) Left: Representative gating strategy for GL7⁺CD38^- GC splenic B cells. Gated on B220⁺ live singlets. Right: Frequency of GC splenic B cells among B220⁺ live singlets after NP-CGG or PBS control immunization. (B) Left: Representative gating strategy for IgG1⁺ cells among splenic B220⁺ live singlets. Right: Quantification of IgG1⁺ switched cells within the GCs of immunized mice. (C) Left: Gating strategy for NP-specific IgG1+ GC B cells. Right: Quantification of NP-specific B cells among IgG1⁺ GC splenic B cells of immunized mice. Data are from 2 experiments with 1 mouse per genotype for control (PBS) group and 2–3 mice per genotype for immunized (NP-CGG) group. Error bars represent mean ± std dev. *P < 0.05 using unpaired, 2-tailed t-test.