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

Meital Gal-Tanamy, Romy Zemel, Larissa Bachmatov, Rohit K. Jangra, Assaf Shapira, Rodrigo A. Villanueva, Min Kyung Yi, Stanley M. Lemon, Itai Benhar, Ran Tur-Kaspa

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)95-106
Number of pages12
JournalAntiviral Research
Issue number1
StatePublished - Oct 2010
Externally publishedYes


  • Hepatitis C virus
  • Inhibitors
  • Intrabodies
  • NS3 protease
  • RNA replicons
  • Single-chain antibodies

ASJC Scopus subject areas

  • Pharmacology
  • Virology


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