Figure 5.

(A) PD-L1 expression in inflamed islets of NOD mice and PD-1 expression on infiltrating cells. Inflamed islets from 10-wk-old unmanipulated prediabetic female NOD mice showing negative staining with isotype control Ig, positive PD-1 staining of infiltrating cells (arrows), positive PD-L1 staining of islets, and negative PD-L2 staining (×400). (B) Injected anti–PD-L1 mAb binds to islets. Inflamed islet, from a 10-wk-old NOD mouse that developed diabetes after injection of anti–PD-L1, showing positive direct staining with anti–rat antibody (×400).