Figure 4: Skewed ratio of T_FH:GC B cells.

(a,b) Immunofluorescence staining of spleen cryosections from SLC^−/− mice. GL7 (green). (a) Detection of CD35⁺ FDC networks. CD35 (red), TCRβ (blue), × 25 objective; scale bar, 50 μm. (b) Detection of CD4⁺ T_FH cells, and those expressing Bcl-6 (arrow). CD4 (red), Bcl-6 (blue), × 40 objective; scale bar, 20 μm. (c–e,g–j) Flow cytometry analysis of spleen cells. (c) CD4⁺PD-1^hi T_FH cells gated on CD4⁺ cells in Ctrl and SLC^−/− mice. (d) Graph shows percentages CD4⁺PD-1^hi T_FH cells gated on CD4⁺ cells. (e) Expression of CD62L on CD4⁺ and CD4⁺PD-1^hi T cells from SLC^−/− mice. (f) QPCR analysis of Bcl6, Cxcr5, Il21, Il4, Ifng, Tgfb1 and Tbx21 (T-bet) mRNA levels in naive CD4⁺PD-1⁻ and CD4⁺PD-1^hi T cells from SLC^−/− mice, with β-actin as internal ctrl. (g) Graph shows ratio of GC B/T_FH cell numbers in SLC^−/− and SRBC-immunized control (Imm. ctrl) mice. (h) Graph shows DZ/LZ ratio in indicated genotypes. (i) Graph shows % Ki-67⁺ cells in the CD19⁺CD95⁺GL7⁺ gate. (j) Graph shows % CaspGlow⁺ (activated caspases) in the CD19⁺CD95⁺GL7⁺ gate. Data are representative from at least two independent experiments except for (g,i,j) day (d) 14 post immunization, which was only performed once. Data in d are pooled from three independent experiments. Each symbol represents one mouse. Data in f are from two independent experiments with at least four mice in each. Error bars represent s.e.m. P values were determined using a two-tailed t-test. *P<0.05, **P<0.01, ***P<0.001; NS, not significant.