LMP1-specific CTLs generated by initial DC_ΔLMP1 stimulations followed by autologous LCL stimulations recognize the HLA-A2–restricted LMP1 epitope YLQQNWWTL (YLQ).

The ability of LMP1-specific CTLs generated by DC_ΔLMP1 stimulations followed by autologous LCL stimulations to secrete IFN-γ in response to the LMP1 peptide YLQ was determined in ELISPOT assays. Spot-forming cells (SFCs) were quantified by Zellnet Consulting. The frequency of YLQ-reactive CTLs was 0.9% in contrast to 0.52% for LMP1-specific CTLs, which were only stimulated with DC_ΔLMP1 (P < .001; Wilcoxon signed rank test)