Figure 2.

GC B Cells in PPs of SAP-Deficient Mice Express Typical Markers

(A) Representative flow cytometry plots showing GC B cells (CD38⁻ FAS⁺) in popliteal LNs (top panel) 7 days after intra-footpad NP-OVA immunization and in PPs of WT, SAP^KO, or TCRα^KO mice.

(B and C) Quantification of GC frequency in popliteal LNs (B) and PPs (C), as in (A).

(D) Representative flow cytometry plots and graph of dark zone (DZ) (CXCR4^hi CD86^lo) and light zone (LZ) (CXCR4^lo CD86^hi) GC B cell distribution in the PPs of WT and SAP^KO mice.

(E) Bcl6 transcript in sorted GC B cells derived from PPs of WT and SAP^KO mice.

(F) Representative histogram and quantification of Bcl6 expression in GC B cells of WT and SAP^KO mice; the naive B cell population is shown as a negative control.

(G) Representative images of mediastinal LNs of influenza-infected mice. LNs were fixed, sectioned, and stained for GL-7 (fluorescein isothiocyanate [FITC], green) and IgD (AF-647, white) to mark the GC and the B cell follicle. Hoechst was used for nuclear staining. Scale bar, 50 μm.

(H) Representative flow cytometry plots showing GC B cells (Ki67⁺ Bcl6⁺) in the mediastinal LNs of WT, SAP^KO, and TCRα^KO mice, 14 days following influenza infection. GC frequencies are summarized in the graph.

Data are pooled from two (B, D–F, and H) and four (C) independent experiments. Each dot represents a single mouse; line represents the mean. ^∗p < 0.05, ^∗∗p < 0.01, ^∗∗∗p < 0.0001, one-way ANOVA with Bonferroni posttest in (B), (C), and (H) and two-tailed Student’s t test in (D)–(F). ns, not significant.