... antibodies to the ligated epitope. In addition, the rare use of the viralcodons by mammalian cells makes expression of the pro-tein very weak, thus difficulting the identification of the epitope-tagged ... investigated, with the exception of deletion R30hE5, increased the number of colonies and the colony size of keratinocytes growing insoft agar. The effect of the empty vector on colony forma-tion ... [9,10].Regarding the interaction of the E5 proteins with the immune system, it has been proposed that its expressionblocks the transport of the major histocompatibility com-plexes to the cell surface...