APC anti-mouse CD8, APC anti-mouse CD4, APC anti-mouse CD3, PE anti-mouse IFN-γ, and PE anti-mouse PD-1 antibodies (Abs) were obtained from BD Biosciences (San Jose, CA). Intracellular cytokine staining (ICS) of IFN-γ was performed as previously described23 (link) using a Cytofix/Cytoperm Plus (with GolgiStop) kit from BD Biosciences. Foxp3 staining was performed using the Foxp3 staining buffer set from eBioscience (San Diego, CA). Appropriate isotype controls were used for the flow cytometric analysis. Flow cytometric data were collected using the BD FACSCalibur flow cytometer (BD Biosciences). Data were analyzed using the Cell Quest (BD Biosciences).