FIGURE 6.

Role of IL-4, IL-21, and Tfr on GC B cell induction and CSR in the presence of BCR engagement. (A) nvB from unimmunized B6 and IL-21R^–/– mice were co-cultured with primed Tfh cells from either Foxp3-eGFP or IL4^–/– mice and stimulated with anti-CD3/anti-IgM in the presence or absence of primed Tfr cells. (B) GC B cells were gated as live Fas⁺GL7⁺B220⁺IgD^lo CD4^–. (C) IgG1⁺ cells were gated as live B220⁺ IgD^loCD4^–. Statistical results are from 10 independent experiments showing SEM (n = 10). *p < 0.05, **p < 0.005, ****p < 0.00001, unpaired Student t-test.