Amino acid substitutions of hepatitis C virus core protein are not associated with intracellular antiviral response to interferon-α in vitro.
BACKGROUND
Studies on patients with hepatitis C virus (HCV) of genotype 1b have suggested that amino acids (aa) 70 and/or 91 of the HCV core protein affect the outcome of interferon (IFN)-α and ribavirin (RBV) therapy, although there are no clear supporting data in vitro.


OBJECTIVE
This study was designed to determine the differences among the antiviral activities of HCV core proteins with various substitutions at aa70 and/or aa91.


METHODS
The retroviral vectors expressing the HCV core proteins with substitutions of arginine/leucine, arginine/methionine, glutamine/leucine or glutamine/methionine at aa70/aa91 were transiently transfected or stably transducted into an immortalized hepatocyte line (PH5CH8), hepatoma cell lines and an HCV-RNA replicating cell line (sOR) to evaluate antiviral responses to IFN-α or IFN-α/RBV. Sequence analysis was performed using genome-length HCV-RNA replicating cells (OR6 and AH1) to evaluate HCV core mutations during IFN-α treatment.


RESULTS
The promoter activity levels of IFN-stimulated genes in the transiently transfected cells or the mRNA levels of 2'-5'-oligoadenylate synthetase in the stably transducted PH5CH8 cells were not associated with the HCV core aa70 and/or aa91 substitutions during IFN-α treatment. Antiviral responses to IFN-α or IFN-α/RBV treatment were enhanced in sOR cells stably transducted with the HCV core, although there were no differences in antiviral responses among the cells expressing different core types. Sequence analysis showed no aa mutations after IFN-α treatment.


CONCLUSIONS
Antiviral activities were enhanced by HCV core transduction, but they were not associated with the HCV core aa70 and/or aa91 substitutions by in vitro analysis.
Ikeda
Fusao
F
Department of Tumor Virology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan. fikeda@md.okayama-u.ac.jp
Dansako
Hiromichi
H
Nishimura
Go
G
Mori
Kyoko
K
Kawai
Yoshinari
Y
Ariumi
Yasuo
Y
Miyake
Yasuhiro
Y
Takaki
Akinobu
A
Nouso
Kazuhiro
K
Iwasaki
Yoshiaki
Y
Ikeda
Masanori
M
Kato
Nobuyuki
N
Yamamoto
Kazuhide
K
D019943:Amino Acid Substitution; D000998:Antiviral Agents / Q000494:pharmacology*; D002461:Cell Line, Transformed; D045744:Cell Line, Tumor; D004359:Drug Therapy, Combination; D016174:Hepacivirus / Q000187:drug effects / Q000235:genetics*; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism / Q000821:virology; D006801:Humans; D016898:Interferon-alpha / Q000494:pharmacology*; D016297:Mutagenesis, Site-Directed; D012254:Ribavirin / Q000494:pharmacology; D020539:Sequence Analysis, Protein; D014162:Transfection; D014758:Viral Core Proteins / Q000235:genetics*
D000998:Antiviral Agents; D016898:Interferon-alpha; D014758:Viral Core Proteins; D012254:Ribavirin