Phenotype of EBNA1-specific T cell subsets is indicative of frequent antigen recognition in MS. The phenotype of EBNA1-specific T cells was assessed on CFSE^low cells proliferating in response to stimulation with the EBNA1 peptide library by CD27, CD28, CD62L, and CXCR3 flow cytometric staining in 24 MS patients and 24 healthy virus carriers. (A) Frequencies of the indicated subsets in MS patients (MS) and healthy controls (HD). (B) Analysis of a representative patient with MS.