Figure 1. GC B Cells Express AIRE.

(A and B) Immunofluorescence analysis of the tonsillar tissue of a healthy donor for IgD, CD19, AIRE and DAPI-stained DNA. The dotted line outlines the follicles. Bars: 100 μm (A) or 25 μm (B).

(C and D) Immunofluorescence analysis of tissues of a healthy donor for IgD, AIRE, CD19 and DNA. Arrow heads indicate follicular IgD⁺ plasmablasts. Dotted lines mark the boundary between follicular mantle zone and the follicle. Bars: 40 μm (C) and 15 μm (D).

(E) Flow cytometric analysis of AIRE expression in tonsillar total CD19⁺ B cells, IgD⁺CD38⁻ naive B cells, IgD⁺CD38⁺ founder GC (FGC) B cells, IgD⁻CD38⁺ GC B cells and IgD⁻CD38⁻ memory B cells. The data represent 5 donors.

(F and G) Flow cytometric and statistical analyses of Aire (GFP) expression in splenic and ILN viable CD19⁺B220⁺FAS⁺GL7⁺ GC B cells, CD19⁺B220⁺FAS⁻GL7⁻ non-GC B cells and CD19^loB220^loCD138⁺ PCs of B6 mice (shaded histograms, n = 5 for spleen and n = 4 for ILN) or B6.Aire^Adig mice (colored histograms, n = 5 for spleen and n = 4 for ILN) after 4 i.p. immunizations with NP₃₂-KLH with CFA and subsequently with IFA. Data are represented as mean ± SEM. **P < 0.01, ***P < 0.001, by 1-way ANOVA with Tukey’s post hoc test.

(H) qPCR analysis of Aire transcript levels in CD19⁺B220⁺FAS⁻GL7⁻ non-GC B cells (n = 5) and CD19⁺B220⁺FAS⁺GL7⁺GFP⁺ Aire-expressing GC B cells (n = 4) of Aire^Adig mice after 1 i.p. immunization with SRBC and CFA. Data are represented as mean ± SEM. ***P < 0.001, by 2-tailed unpaired t-test.

(I) Flow cytometric and statistical analyses of CD83⁺CXCR4^lo LZ and CD83⁻CXCR4^hi DZ B cells in splenic total GC and GFP⁺ GC B cells of immunized B6.Aire^Adig mice, by 2-tailed paired t-test.

(J and K) Immunofluorescence analysis of the tonsillar tissue of a healthy donor for IgD, CD23, Pax5 and AIRE. The dotted line outlines the follicles and delineates the border between LZ and DZ. Bars: 200 μm (J) or 30 μm (K).