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. 2011 Aug 1;108(33):E488–E497. doi: 10.1073/pnas.1100898108

Fig. 6.

Fig. 6.

CXCR5loICOSlo CD4+ T cells induce apoptosis of GC-B cells through the FAS/FAS-L interaction. (A) Expression of cell surface FAS by GC-B cells. (B) Soluble FAS-L production by Th populations cocultured with GC-B cells. FAS-L concentrations at day 2 (n = 4). One-way ANOVA Bonferonni multiple comparison test. ***P < 0.001, **P < 0.01, and *P < 0.05. (C) FASLG mRNA expression by tonsillar Th populations analyzed by real-time RT-PCR. Expression of FASLG transcript was normalized to that of HPRT1 transcript (n = 3). (D) Ig secretion by GC-B cells cocultured with tonsillar Th populations in the presence of FAS mAb. Ig concentrations were measured at day 8 (a representative from four experiments). (E) Ig secretion by naïve B cells cocultured with CXCR5−ICOS− CD4+ T cells, CXCR5loICOShi CD4+ T cells, or CXCR5hiICOShi GC-Tfh cells supplemented with titrated doses of recombinant IL-21. Ig secretion measured at day 8 (a representative from two experiments).