Frequencies of EBNA1-specific CD4⁺ T-cell responses are stable over time. (A) The frequency of EBNA1-specific IFNγ-expressing CD4⁺ T cells (♦) was assessed at the indicated time points in comparison to the frequencies of IFNγ-expressing CD4⁺ T cells in response to medium (⋄) and CMV-derived CD8⁺ T-cell epitopes (□). (B) The average EBNA1 subpool (EBNA1_400-461; Table S1) recognition was determined from the assays conducted at the 7 different time points, indicated in panel A. Standard deviations are depicted. The data are representative for 3 healthy EBV carriers that were analyzed at 7 or more time points.