Fig. 4

MBCs differentiate into plasma cells in SPF. a Representative histological section of lymph node 3 days after secondary immunisation. CD35 (blue), Ki67 (red), HEL binding (green), B220 (pink). Scale bar = 100 μm. b Quantification of Ki67 intensity on HEL-binding cells in SPF, n = 57, or GC, n = 72, from a. Comparison between groups utilised Mann–Whitney U test. c Quantification of HEL-binding intensity on HEL-binding cells in SPF, n = 57, or GC, n = 72, from a. Comparison between groups utilised Mann–Whitney U test. d Orthogonal maximum intensity projection (200 × 200 × 10 μm) 3 days after secondary immunisation showing Blimp-1⁺ cells (green), Tfh cells (cyan), SHG (blue). Note autoflourescent macrophages. Scale bar = 20 μm. e Representative histological section of lymph node 5 days after HEL-OVA re-immunisation. CD35 (blue), Bcl6 (red), HEL binding (green). Scale bar = 100 μm. f Quantification of Bcl-6 intensity on HEL⁺ cells in SPF B cells, n = 26, or GC B cells, n = 46. Data are representative of 5 independent experiments. Comparison between groups utilised Mann–Whitney U test. Box plots show centre line as median, box limits as upper and lower quartiles, whiskers as minimum to maximum values