The majority of the GC-derived B cells enter the LN cortex. (A) LSFM 3D-rendered images of LNs removed from AID.Cre.tdTomato, AID-GFP, or AID.Cre.ERT2.tdTomato mice 12–14 d after immunization with NP-OVA. AID.Cre.ERT2.tdTomato mice were treated with either oil control or tamoxifen for 4 d. Scale bar, 200 μm. (B and C) GC number per LN (B) and number of individual non-GC cells per LN (C). Representative images and pooled data for A–C from two to five independent experiments with a total of four to eight LNs from four mice per group. ***, P < 0.0001; one-way ANOVA with Tukey’s multiple comparisons test. (D) Tamoxifen-treated AID.Cre.ERT2.tdTomato mice that received GFP⁺ T cells and CFP⁺ B cells 14 d after immunization with NP-OVA. Representative 3D-rendered images of an LN are shown. Scale bar, 200 μm. (E) Quantification of the number of individual tdTomato⁺ B cells in the T zone and in B cell follicles in single LNs after GC exclusion. Each pair of colored dots represents a single LN. *, P < 0.05; Wilcoxon matched-pairs signed rank two-tailed test. (F) The ratio of the number of individual tdTomato⁺ B cells in the B zone versus the T zone in individual LNs. Representative images and data were pooled for D–F from three independent experiments using a total of seven LNs from five mice.