CD4⁺ T cells specific for DYS peptide are present at high frequency in peripheral blood. PBMCs from CMV-seropositive donors were stimulated with DYS peptide or CMV lysate, and antigen-specific CD4⁺ T cells were detected by intracellular IFN-γ expression. (A) Representative flow cytometric profiles from HLA-DRB*0701–positive donors (08 and 07) and an HLA-DRB*070–negative donor showing the DYS-specific CD4⁺ T-cell response. (B) DYS peptide and CMV lysate–specific CD4⁺ responses from the cohort of HLA-DRB*0701–positive, CMV-seropositive donors (n = 10). Horizontal lines link the DYS-specific and CMV lysate–specific responses from individual donors, each shown as a percentage of CD4 T cells.