The tumor biopsy cells had a deletion in the EBNA-3B gene that removed the 2 immunodominant CTL epitopes.

(A) The tumor cells have a deletion in the EBNA-3B gene; 200 ng DNA from each of the indicated cell lines and from tumor biopsy cells taken 17 days after CTL infusion was amplified using primers that spanned the second to fourth HLA-A11–restricted epitopes in EBNA-3B. These were expected to generate a fragment of 593 base pairs in wild-type EBV. The products were run on a 2% agarose gel and stained with ethidium bromide. (B) Sequence of EBNA-3B deletion in the pre-CTL tumor line; 200 ng DNA from the pre-CTL tumor line and from BL41/B95-8 was amplified and sequenced using primers described by de Campos-Lima et al.35 This figure shows a comparison of a partial sequence of the EBNA-3B protein of B95-8 EBV, from amino acids 382 to 612 (of a total of 964 amino acids), with the same region of EBNA-3B from the patient-derived tumor cell line established prior to CTL infusion. HLA-A11–restricted epitopes are in bold.