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We have previously demonstrated that hepatitis C virus (HCV) core protein regulates cellular protooncogenes at the transcriptional level; this observation implicates core protein in the alteration of normal hepatocyte growth. In the present study, the transforming potential of the HCV core gene was investigated by using primary rat embryo fibroblast (REF) cells which were transfected with or without cooperative oncogenes. Integration of the HCV core gene resulted in expression of the viral protein in REF stable transformants. REF cells cotransfected with HCV core and H-ras genes became transformed and exhibited rapid proliferation, anchor-independent growth, and tumor formation in athymic nude mice. Results from these studies suggest that the core protein plays an important role in the regulation of HCV-infected cell growth and in the transformation to tumorigenic phenotype. These observations suggest a possible mechanism for this viral protein in the pathogenesis of hepatocellular carcinoma in HCV-infected humans.

Although excessive alcohol consumption in combination with hepatitis C virus (HCV) infection is known to increase the risk of liver cirrhosis, the effect of moderate alcohol intake remains to be elucidated. The aim of this study was to evaluate the effect of moderate alcohol consumption on fibrosis progression in HCV infection. A group of 78 patients with HCV infection and moderate alcohol consumption were analysed retrospectively. All patients had undergone two liver biopsies, with a median time between biopsies of 6.3 years, and had not received any antiviral therapy. Their lifetime drinking history was recorded. All patients except one had daily alcohol consumption below 40 g of ethanol (median 4.8 g/day, interquartile range 1.1-11.6 g/day) during the period between the biopsies. The patients whose liver fibrosis had deteriorated had a higher total alcohol consumption and higher drinking frequency between the biopsies. The degree of fibrosis progression was greater in patients with a total alcohol intake and drinking frequency above the median level for the group. A multiple logistic regression analysis showed that drinking frequency and time between biopsies were independently associated with fibrosis progression. Hence, even moderate alcohol intake seems to increase fibrosis progression in HCV-infected patients. From that point of view, total abstention ought to be recommended. If this is not achieved, occasional use of alcohol is probably less harmful than daily drinking for patients with low or moderate alcohol consumption.

The putative envelope glycoproteins of hepatitis C virus (HCV) likely play an important role in the initiation of viral infection. Available information suggests that the genomic regions encoding the putative envelope glycoproteins, when expressed as recombinant proteins in mammalian cells, largely accumulate in the endoplasmic reticulum. In this study, genomic regions which include the putative ectodomain of the E1 (amino acids 174 to 359) and E2 (amino acids 371 to 742) glycoproteins were appended to the transmembrane domain and cytoplasmic tail of vesicular stomatitis virus (VSV) G protein. This provided a membrane anchor signal and the VSV incorporation signal at the carboxy termini of the E1 and E2 glycoproteins. The chimeric gene constructs exhibited expression of the recombinant proteins on the cell surface in a transient expression assay. When infected with a temperature-sensitive VSV mutant (ts045) and grown at the nonpermissive temperature (40.5°C), cells transiently expressing the E1 or E2 chimeric glycoprotein generated VSV/HCV pseudotyped virus. The resulting pseudotyped virus generated from E1 or E2 surprisingly exhibited the ability to infect mammalian cells and sera derived from chimpanzees immunized with the homologous HCV envelope glycoproteins neutralized pseudotyped virus infectivity. Results from this study suggested a potential functional role for both the E1 and E2 glycoproteins in the infectivity of VSV/HCV pseudotyped virus in mammalian cells. These observations further suggest the importance of using both viral glycoproteins in a candidate subunit vaccine and the potential for using a VSV/HCV pseudotyped virus to determine HCV neutralizing antibodies.

Hepatitis C virus (HCV) is a major causative agent of parenterally transmitted non-A, non-B hepatitis. The genomic region encoding the virion-associated core protein is relatively conserved among HCV strains. To generate a DNA vaccine capable of expressing the HCV core protein, the genomic region encoding amino acid residues 1 to 191 of the HCV-1 strain was amplified and cloned into an eukaryotic expression vector. Intramuscular inoculation of recombinant plasmid DNA into BALB/c mice (H-2 d) generated HCV core-specific antibody responses, lymphoproliferative responses, and cytotoxic T-lymphocyte activity. Our results suggest that the HCV core polynucleotide warrants further investigation as a potential vaccine against HCV infection.

Hepatitis C virus (HCV) accounts for most cases of acute and chronic non-A and non-B hepatitis with serious consequences that may lead to hepatocellular carcinoma. The putative envelope glycoproteins (El and E2) of HCV probably play a role in the pathophysiology of the virus. In order to map the immunodominant domains of the El glycoprotein, two epitopes from amino acid residues 210 to 223 (P1) and 315 to 327 (P2) were predicted from the HCV sequence. Immunization of mice with the synthetic peptides conjugated to bovine serum albumin induced an antibody response, and the antisera immunoprecipitated the El glycoprotein (-33 kDa) of HCV expressed by recombinant vaccinia virus. A panel of HCV-infected human sera was also tested with the synthetic peptides by enzyme-linked immunosorbent assay for epitope-specific responses. Of 38 infected serum samples, 35 (92.1%) demonstrated a spectrum of reactivity to the P2 peptide. On the other hand, only 17 of 38 (44.7%) serum samples were reactive to the P1 peptide. Strains of HCV exhibit a striking genomic diversity. The predicted Pl epitope showed localization in the sequence-variable region, and the P2 epitope localized in a highly conserved domain. Results from this study suggest that the El glycoprotein of HCV contains at least two potential antigenic epitopes. Synthetic peptides corresponding to these epitopes and antisera to these peptides may serve as the monospecific immunological reagents to further determine the role of El glycoprotein in HCV infection.

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