Inhibition of protease-inhibitor-resistant hepatitis C virus replicons and infectious virus by intracellular intrabodies.


Hepatitis C virus (HCV) infection is a common cause of chronic liver disease and a serious threat to human health. The HCV NS3/4A serine protease is necessary for viral replication and innate immune evasion, and represents a well-validated target for specific antiviral therapy. We previously reported the isolation of single-chain antibodies (scFvs) that inhibit NS3/4A protease activity in vitro. Expressed intracellularly (intrabodies), these scFvs blocked NS3-mediated proliferation of NS3-transfected cells. Here we show that anti-NS3 scFvs suppress HCV RNA replication when expressed intracellularly in Huh7 hepatoma cells bearing either subgenomic or genome-length HCV RNA replicons. The expression of intrabodies directed against NS3 inhibited the autonomous amplification of HCV replicons resistant to small-molecule inhibitors of the NS3/4A protease, and replicons derived from different HCV genotypes. The combination of intrabodies and interferon-α had an additive inhibitory effect on RNA replication in the replicon model. Intrabody expression also inhibited production of infectious HCV in a cell culture system. The NS3 protease activity was inhibited by the intrabodies in NS3-expressing cells. In contrast, cell-free synthesis of HCV RNA by preformed replicase complexes was not inhibited by intrabodies, suggesting that the major mode of inhibition of viral replication is inhibition of NS3/4A protease activity and subsequent suppression of viral polyprotein processing.

DOI: 10.1016/j.antiviral.2010.08.001

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@article{GalTanamy2010InhibitionOP, title={Inhibition of protease-inhibitor-resistant hepatitis C virus replicons and infectious virus by intracellular intrabodies.}, author={Meital Gal-Tanamy and Romy Zemel and Larissa Bachmatov and Rohit K. Jangra and Assaf Shapira and Rodrigo A Villanueva and Minkyung Yi and Stanley M Lemon and Itai Benhar and Ran Tur-kaspa}, journal={Antiviral research}, year={2010}, volume={88 1}, pages={95-106} }