Amino acid substitutions in NS5A region of GB virus C and response to interferon therapy

Takanobu Kato, Masashi Mizokami, Etsuro Orito, Ken Ichi Ohba, Tatsunori Nakano, Yutaka Kondo, Yasuhito Tanaka, Ryuzo Ueda, Motokazu Mukaide, Kiyomi Yasuda, Shiro Iino

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6 Citations (Scopus)


GB virus C (GBV-C) is related to hepatitis C virus (HCV) and has a similar genomic structure. Some predictors for the efficacy of interferon (IFN) therapy on HCV have been reported: geno-type, viral load, IFN dose, and the amino acid substitutions in the NS5A region, designated as the interferon sensitivity determining region (ISDR). To evaluate the correlation between the amino acid substitutions in the GBV-C NS5A region and the response to IFN therapy, single-strand conformation polymorphism (SSCP) analysis was performed in the 12 concomitantly GBV-C-and HCV-infected patients who received IFN therapy at three time points: before, end-point, and after the IFN therapy. The region in the GBV-C NS5A studied includes the amino acids that exhibit some homology to the ISDR and the various substitutions. By SSCP analysis, amplicons were separated into 1-4 bands, which indicated the existence of heterogeneity in each host. However, the deduced amino acid sequences in these bands exhibited no characteristic differences among these strains irrespective of response to IFN therapy. Of the 32 strains separated by SSCP, 7 strains were responders, and 25 were nonresponders. The mean amino acid substitution, compared with the consensus sequence of nonresponders, was 1.00 ± 0.93 among responders, and 1.40 ± 0.85 among nonresponders (P = NS). No correlation between the amino acid sequence in the GBV-C NS5A region and response to IFN therapy was found, indicating that the GBV-C NS5A region dose not act as the ISDR.

Original languageEnglish
Pages (from-to)376-382
Number of pages7
JournalJournal of Medical Virology
Issue number4
Publication statusPublished - 1999
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Virology
  • Infectious Diseases


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