Fig. 4.

In the absence of high B7-DC levels, B7-H1 is also important for the concentration of PD-1 at the immunological synapse. (A) Splenic DCs from WT or B7-H1^−/− B6 mice were purified and cultured as in Fig. 2. The WT DCs are in red (LPS) and blue (IL-4), and the B7-H1^−/− cells are in green (LPS) and orange (IL-4). (B) OT-II T cells were infected with CD28-YFP or PD-1-YFP. PKC θ is in blue, PD-1 is in yellow, and CD11c is in red. The images show conjugates using B7-H1^−/− DCs. (Upper) A representative cell with concentrated PD-1. (Lower) A cell with uniform distribution of PD-1. (C) The statistics from three experiments with at least 30 conjugates are shown as mean and SD (error bars). The numbers after the bars are the same as in Fig. 2. (D) The ratios of the fractions of concentrated cells (knockout DCs relative to WT DCs) from three experiments using OT-II T cells and WT, B7-H1^−/−, or B7-DC^−/− DCs that were treated with GM-CSF and either LPS or IL-4 are shown as mean and SD (error bars).