B cell entry into the LN cortex is regulated by BCR affinity. (A) Representative LSFM 3D-rendered images of LNs removed from immunized MD4 host mice that were adoptively transferred with DsRed⁺ B1-8^hi or DsRed⁺ B1-8^lo B cells. Scale bar, 200 μm. (B–E) Analysis of number of individual cells per LN (B), GC volume (C), number of non-GC individual cells normalized to the total GC volume (D), and proximity index (E). Representative images and data for A–E were pooled from three independent experiments with a total of 11–13 LNs from  seven to eight mice per group. **, P < 0.01; ***, P < 0.0001; ns, not significant; two-tailed Student's t test.