Figure 6

Roles of cytokines in maintenance and induction of PD-1-expressing T cells. Survival (A), proliferation (B), and changes in expression of CXCR5 and CCR7 (C) and PD-1 (D) by the T cell subsets were examined. (E) IL21 and IL6 fail to induce the expression of CXCR5, IL21, and CXCL13 at the mRNA level by antigen-primed naïve T cells. Relative expression levels after normalization with the expression levels of β-actin are shown in panel E. For all panels, indicated T cells were cultured for 5-6 days in the absence or presence of T cell activators with IL2, IL7 or IL21. Combined data of 3 independent experiments (A-D) or a representative real-time PCR data (E) are shown."*" and "**"indicate significant differences from naïve T cells and PD-1⁺⁺ cells respectively. "ND" indicates non-detectable.