Extended Data Figure 6: DC CD25 expression reduces IL-2 signalling in activated CD4 T cells, favouring their differentiation to follicular helpers.

a, Diagram of CD25 KO:Zbtb46-DTR BM chimaera generation and time line of experiment. DTx, DT treatment. b–d, Numbers (b), surface marker expression (c) and outer T zone positioning (d) of CD4⁺ DCIR2⁺ DCs in WT:Zbtb46-DTR and CD25 KO:Zbtb46-DTR mixed BM chimaeras pre-treated with DT, at day 1 after saline or SRBC immunization. e, Number of Foxp3⁺ CD25⁺ regulatory T cells in mice of the type in b except that the mice were immunized for three days. f, Immunohistochemical analysis of spleen sections from mice of the type in b, stained to detect IgD (blue) and CD25 (brown). g, h, Frequency and number of CXCR5⁺PD-1^hi control (EBI2 Het) and EBI2 KO OTII T cells in spleens (g) or lymph nodes (h) from WT:Zbtb46-DTR or CD25 KO:Zbtb46-DTR mixed BM chimaeras pre-treated with saline or DT, at day 3 after immunization with Listeria-OVA (g) or alum-OVA (h). i, j, Flow cytometric analysis for HEL-binding CD138⁺ plasma cells (i) and HEL-binding GL7⁺ Fas⁺ germinal centre B cells (j) in spleens from WT:Zbtb46-DTR (control) or CD25 KO:Zbtb46-DTR mixed BM chimaeras that had received Hy10 B cells and been treated with DT, at day 5 after immunization with HEL-SRBC. k, Soluble CD25 detected by ELISA in spleen extracts taken from 12 h SRBC immunized mice, at day 1 after saline or recombinant CD25 treatment. **P < 0.01 by Student’s t-test (h, k). Data are representative of two independent experiments with at least three (b, c, g–k) or two (d, f) mice per group (error bars (k), s.e.m.).