INHIBITION OF HEPATITIS-B VIRUS IN-VITRO BY ANTISENSE OLIGONUCLEOTIDES

A series of antisense phosphorothioate oligodeoxynucleotides against h epatitis B virus (HBV) were synthesized and evaluated for their antivi ral effect in Hep-G(2) cells transfected with HBV genome. The inhibito ry effect of the tested antisense oligonucleotides was sequence-specif ic, dose- and time-dependent, and synergistic for certain combinations . In virus-inhibitory concentrations the oligonucleotides were harmles s to 2.2.15 cells. The most effective antisense oligonucleotides were found directed against the HBV mRNA transcribed from the cap site of S P II promoter, the portion of polyadenylation signal and the initiatio n region of gene S, with an inhibition of the HBsAg and HBeAg producti on by 85 - 95% and 50 - 60%, respectively. To our surprise, antisense oligonucleotides directed against three key sites of HBV X gene blocke d the expression of HBsAg, HBeAg and HBxAg. This fact might be related to the trans-activation of HBV X protein. Using radioisotope labellin g, we demonstrated that Lipofectin promoted the cellular uptake and an tiviral effect of antisense oligomers in 2.2.15 cells. These results s uggest a therapeutic potential of antisense oligonucleotides in the tr eatment of patients chronically infected with HBV.