Figure 3

Expression of surface antigens, cytokines, and costimulatory molecules by PD-1-expressing T cells. (A) Flow cytometric analysis of the surface antigen expression by freshly isolated tonsil T cells is shown as graphs and dot plots. (B) Intracellular cytokine expression by CXCR5⁺ PD-1⁺ CD4⁺ T cells. The T cells were surface-stained and, then, activated with PMA and ionomycin in the presence of monensin for 4 h. The CXCR5⁺ PD-1⁺ CD4⁺ T cells are gated excluding the largely PD-1-negative naive T cells. Representative data out of 3 independent experiments are shown. (C) Surface expression of ICOS and OX40 and intracellular expression of CD40L by freshly prepared PD-1-expressing T cells. Combined data of 3 independent experiments are shown in the graphs. "*" and "**"indicate significant differences from naïve T cells and PD-1⁺⁺ cells respectively.