IDO-inducing agents expanded IDO-specific T cells with supporter functions. Example of reactivity against IDO5 (IDO_199-207; ALLEIASCL) in PBMCs from an HLA-A2⁺ healthy donor, stimulated in vitro with IL-2 and IFN-γ. The percentage of IDO5-specific CD8⁺ T cells was identified by flow cytometry, ex vivo (top) and after stimulation (bottom), using the MHC-tetramer complex HLA-A2/IDO5 and CD8 monoclonal antibody (mAb). The data shown are from 1 donor, representative of 4 different donors (A). Examples of reactivity against IDO5 in PBMCs from a patient with HLA-A2⁺ renal cell carcinoma, stimulated in vitro with IL-2 and CTLA4-Ig (B) or CpG ODN (C). The percentage of IDO5-specific CD8⁺ T cells was identified by flow cytometry, ex vivo (top) and after stimulation (bottom), using the MHC-tetramer complex HLA-A2/IDO5 and CD8 mAb. The data shown are from 1 patient, representative of 2 different patients (B-C). PBMCs from an HLA-A2⁺ healthy donor stimulated in vitro with CMV pp65_495-503 (NLVPMVATV) peptide and cocultured with either autologous, isolated CD8⁺ T cells (top) or autologous, isolated IFN-γ–induced IDO5-specific T cells (bottom). The percentage of CMV pp65_495-503–specific CD8⁺ T cells in each culture was identified by flow cytometry with the MHC-tetramer complex HLA-A2/CMV pp65_495-503 and CD8 mAb (D). PBMCs from an HLA-A2⁺ healthy donor stimulated with CMV IE1_316-324 (VLEETSVML) peptide and cocultured with either autologous, isolated CD8⁺ T cells (top) or autologous, IDO5-specific T cells isolated after 2 in vitro peptide stimulations (bottom). The percentage of CMV IE1_316-324–specific CD8⁺ T cells in each culture was identified by flow cytometry with the MHC-tetramer complex HLA-A2/ CMV IE1_316-324 and CD8 mAb (E). In all experiments, cells were stained with the MHC-tetramer complex HLA-A2/HIV-1 pol_476-484 and CD8 mAb for comparison.