Tregitopes can modulate CTL responses directed against several antigens and in the context of different HLA alleles . ( a–d ) Teff specific for Epstein-Barr virus (EBV), cytomegalovirus (CMV), hepatitis C virus (HCV), or influenza virus (Flu) were obtained following the protocol outlined in Figure S1. All MHC I epitopes were HLA-B*0702-restricted. Teff were used in the CTL assay at a Teff:target ratio of 1:10. Targets were peptide loaded with increasing concentrations of the relevant peptide. Results are expressed as % cytotoxicity compared to a max cytotoxicity (cells treated with 10% SDS) after background subtraction. Dashed line, Teff expanded from PBMC restimulated in vitro with indicated viral peptide only; Black line, Teff expanded in vitro with indicated viral peptide and hTreg167. ( e ) CTL assay in which Tregitope efficacy was tested against the AAV HLA-A*0101 restricted MHC I epitope SADNNNSEY. HLA-matched Teff were used in the CTL assay at a Teff:target ratio of 1:10. Targets were peptide loaded with increasing concentrations of the relevant peptide. Results are expressed as % cytotoxicity compared to a max cytotoxicity (cells treated with 10% SDS) after background subtraction. Dashed line, effectors obtained by restimulating PBMC in vitro with the SADNNNSEY epitope only; Black line, restimulation of PBMC was performed with the SADNNNSEY epitope from AAV and hTreg167. ( f ) CTL assay in which targets were loaded with the HLA-B*0702 epitope VPQYGYLTL from AAV. Teff were either obtained restimulating PBMC with the same AAV peptide only (AAV), or with the AAV peptide and Tregitope 167 (AAV+hTreg167), or with the AAV peptide and Tregitope 289 (AAV+hTreg289). Teff were used in the CTL assay at a Teff:target ratio of 1:10. Targets were peptide loaded with increasing concentrations of the relevant peptide. Results are expressed as % cytotoxicity compared to a max cytotoxicity (cells treated with 10% SDS) after background subtraction. Experiments shown were repeated at least twice. Error bars represent SEM.