EBV(Epstein-Barr virus), like other human herpesviruses, possesses two phases in its life cycle: latent and lytic stages. In vitro, however, EBV can be triggered into lytic cycle in the presence of the chemicals or cytokines, such as 12-O-tetradecanoyl -phorbol-13-acetate(TPA), n-sodium butyrate(SB), or TGF-