Analysis of the LMP1 repeat revealed 2 viruses in the recipient before CTL infusion.

Primers spanning the LMP1 repeat region were used to amplify viral DNA. The amplification products were run on a 2% agarose gel, Southern blotted, and probed with an LMP1 complementary DNA probe. Two polymorphisms within the LMP1 repeat were detected prior to CTL infusion in the peripheral blood and the pre-CTL tumor line. After CTL infusion, the virus with the smaller repeat was not detectable in the peripheral blood, whereas the virus with the larger repeat persisted. In the post-CTL tumor line, the relative abundance of the virus with the smaller repeat was much reduced.