ANTISENSE OLIGODEOXYNUCLEOTIDES AGAINST THE BZLF1 TRANSCRIPT INHIBIT INDUCTION OF PRODUCTIVE EPSTEIN-BARR-VIRUS REPLICATION

Expression of the Epstein-Barr virus (EBV) BZLF1 gene product, ZEBRA, in latently infected cells is sufficient to induce the viral lytic cyc le. The use of oligodeoxynucleotides complementary to the BZLF1 transc ript was studied to inhibit this induction of productive viral replica tion. For this purpose, we employed oligodeoxynucleotides complementar y to the translation initiation codons and their flanking sequences. I ncubation of Akata cells with the 25-mer phosphodiester (PO)- or phosp horothioate (PS)-antisense oligodeoxynucleotides for 3 h before stimul ation with anti-immunoglobulin G antibodies (anti-IgG) partially inhib ited the anti-Igc-mediated induction of ZEBRA synthesis. Both the PO- and PS-antisense oligodeoxynucleotide treatments also suppressed the p roductive EBV replication (as measured by linear DNA production) in a dose-dependent manner, with much greater efficiency than did PO- and P S-oligodeoxynucleotides with sense, reverse or random sequences of the same length. Another 20-mer antisense oligodeoxynucleotide complement ary to sequences downstream of the translation initiation codons showe d a similar inhibitory effect on EBV replication. However, the inhibit ion was considerably lower when the cells were treated with oligodeoxy nucleotides complementary to sequences upstream of the start codons. T hese results indicate that BZLF1 antisense oligodeoxynucleotides inhib it the viral activation in a sequence-specific fashion. In the virus-p roducer cell line P3HR-1, the same PS-antisense oligodeoxynucleotides also partially suppressed the spontaneous viral replication after 6-10 days, substantially more than the PS-random oligodeoxynucleotides. In hibition of BZLF1 appears to be sufficient to suppress the induction o f EBV replication.