Extended Data Figure 4: T-cell EBI2 is required for CD4⁺ DC-mediated augmentation of Tfh cell induction.

a, Frequency and number of CXCR5⁺PD-1^hi OTII T cells in μMT recipients determined by flow cytometric analysis. b, Flow cytometric analysis for CD11c and MHC class II on splenocytes from Zbtb46-DTR mice treated with saline or DT for 1 day. Graph shows summary data for DC number in four mice of each type. c, Frequency and number CXCR5⁺PD-1^hi WT and EBI2 KO OTII T cells in spleens from Zbtb46-DTR BM chimaeras treated with saline or diphtheria toxin (DT), at day 3 after immunization with SRBC-OVA. d, Immunohistochemical analysis of spleen sections from WT mice without immunization (saline) or SRBC immunized for the indicated times, stained to detect IgD⁺ B cells (blue) and DCIR2⁺ DCs (brown). e, Immunohistochemical analysis of spleen sections from recipients of WT or EBI2 KO OTII T cells at 12 h and 1 day after immunization SRBC-OVA immunization, stained for OTII CD45.1⁺ T cells (blue) and DCIR2⁺ DCs (brown). f, Immunohistochemical analysis of spleen sections from WT:Zbtb46-DTR or CCR7 KO:Zbtb46-DTR mixed BM chimaeras treated with DT, at day 2 after immunization. g, Frequency and number of CXCR5⁺PD-1^hi WT and EBI2 KO OTII T cells in spleens from WT:Zbtb46-DTR (control) or CCR7 KO:Zbtb46-DTR mixed BM chimaeras treated with DT, at day 3 after immunization. h, Frequency and number of CXCR5⁺PD-1^hi control (het) and EBI2 KO co-transferred OTII T cells in spleens of CD47 KO recipients at day 3 after SRBC-OVA immunization. i, Number of total and CD4⁺ DC in spleens from Irf4^f/f CD11c-Cre^– or ⁺ mice. j, As for g but in Irf4^f/f CD11c-Cre^– or ⁺ recipient mice. k, As for g but in Batf3 KO recipient mice. l, ICOSL surface levels for DCs from mice immunized 12 h earlier with saline or SRBCs and treated with control or ICOS blocking antibody. m, ICOSL surface levels for CD4⁺ or CD8⁺ DCs from CD28 KO mice immunized 12 h earlier with saline or SRBCs. n, Il6 and Tgfβ mRNA abundance in sorted CD4⁺ and CD8⁺ splenic DCs from mice treated with saline or SRBC 6 h earlier, determined by RT–qPCR, shown relative to the control CD8⁺ DC. **P < 0.01 by ANOVA (g, k) or Student’s t-test (a–c, i, j, m). Data are representative of three (a–e) or two (f–n) independent experiments with at least three (a–c, g–n) or two (d–f) mice per group (error bars (n), s.e.m.).