Because the expression of EBNA1 is prevalent in all EBV-associated tumors, it has become one of the most attractive drug targets for the discovery of anti-EBV compounds. In a cell-based reporter system, EBNA1 consistently upregulated the transcription of an oriP-Luc mini-EBV episome by 6- to 8-fold. The treatment of cells with 50 mu M EGCG effectively blocked the binding of EBNA1 to oriP-DNA both in vivo and in vitro, which led to the abrogation of EBNA1-dependent episome maintenance and transcriptional enhancement. Importantly, the anti-EBNA1 effects caused by EGCG ultimately impaired the persistence of EBV latent infection. Our data suggest that the inhibition of EBNA1 activity by EGCG could be a promising starting point for the development of new protocols for anti-EBV therapy. (C) 2011 Elsevier Inc. All rights reserved.