Reactivation of EBV after B-cell transfer. (A) EBV copy numbers before (V2) and after B-cell transfer. Maximal values of EBV copy numbers are depicted for observation periods V3 to V10. (B) Representative FACS analysis of IFNγ production in CD8⁺ T cells after stimulation with 5 PepTivator peptide mixes derived from EBV proteins (EBNA1, BMLF1, BZLF1, LMP1, and BRLF1). (C) Frequency of IFNγ-producing CD8 and CD4 cells after stimulation with EBV PepTivator peptide mixes. The respective maximal values of 2 time points analyzed after B-cell transfer (days 7 and day 14) are shown.