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Summary. Hepatitis C virus (HCV) infection is a major cause for chronic liver disease and hepatocellular carcinoma. The HCV-ARF/core+1 protein is an alternative product of HCV core-encoding sequence of unknown biological function. Highly purified HCV core and ARF/core+1 recombinant proteins from HCV genotype 1a and HCV-ARF/core+1 recombinant protein from HCV genotype 3a were expressed in Escherichia coli. Using an enzyme-linked immunosorbent assay, we assessed the prevalence of anti-ARF/core+1 antibodies in 90 chronic hepatitis C patients infected with HCV genotypes 1a/1b or 3a, treated with pegylated interferon (Peg-IFN-a-2a) plus ribavirin. Samples derived from 92 healthy blood donors were used as negative controls. All HCV-RNA-positive serum samples reacted with core 1a antigen, while 15 (37.5%) of 40 and 14 (28%) of 50 patients infected with HCV-1a/1b and HCV-3a, respectively, were found to have anti-ARF/core+1 antibodies into their serum before treatment initiation. These antibodies were persistently present during treatment follow-up and linked to elevated levels of HCV-RNA at baseline. [ABSTRACT FROM AUTHOR]

Summary. Two herpes simplex type 1 (HSV-1) recombinant viruses carrying the hepatitis C virus (HCV) NS5A open reading frame under the control of the cytomegalovirus immediate early (IE) or a herpes simplex chimeric promoter (α4γ1UL19) were constructed and characterized. Expression studies showed that both HSV-NS5A recombinant viruses were able to express high levels of the NS5A protein in infected cells. Most importantly, using this system, we demonstrated that the NS5A protein interacts with the growth receptor-bound protein 2 (Grb2) and inhibits the phosphorylation of the extracellular signal-regulated kinases 1 and 2 (ERK1/2) in HeLa, NIH3T3 or liver infected cells. Thus, our studies confirm the ability of the NS5A protein to perturb the extracellular signal-regulated kinase (ERK) pathway in HeLa cells by the use of an alternative system for NS5A expression and extend this observation to additional cell lines. We conclude that HSV-based viral vectors may provide a useful system for studying the expression and selected functional properties of the HCV NS5A protein. [ABSTRACT FROM AUTHOR]

Summary. In this study different forms of the hepatitis C virus (HCV) NS5A protein, including a nearly full-length, an amino-terminal and a carboxy-terminal truncated form were produced in E. coli as fusion proteins with the MBP or the GST protein. The chimeric proteins were tested for their reactivity with sera from HCV infected patients by immunoblot and ELISA assays. A panel of 110 sera specimens, including 39 HCV-positive sera, 27 sera from patients with non-HCV-associated liver disease and 44 healthy individuals were analyzed for the presence of antibodies to NS5A. Twenty four (61 %) out of the 39 HCV positive sera, showed reactivity against the nearly full length NS5A, 21 (54 %) against the amino-terminal part of NS5A and 20 (51 %) against the carboxy-terminal part of the NS5A protein in immunoblot assays, suggesting that immunoreactive epitopes are present both at the carboxy- and the amino- terminal part of the protein. None of the 71 HCV-negative serum samples showed any reactivity against the NS5A antigens. With the exception of one patient, similar data were obtained with an ELISA assay based on the use of the nearly full-length NS5A antigen. The data indicate that new forms of NS5A may be potentially valuable antigens for the development of serological assays for HCV. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the possible association of human papillomaviruses (HPV) with the development of squamous cell lung carcinomas (SqCLCs). Tissue material from 52 cases of SqCLCs were studied, and the data were evaluated according to the degree of differentiation, HPV presence and type. Analysis was performed by polymerase chain reaction (PCR) method using consensus primers, and the results were confirmed by subsequent Southern blot hybridization. Overall, the results showed 69% positivity (n=32). Forty-one cases were examined for the presence of specific HPV types (6/11 and 16/18) by hybridization of the PCR products with 32P-labelled probes. HPV 6/11 types were detected in 6 of the 29 positive cases (20.6%). HPV 16/18 types were the most prevalent types, and were detected in 11/29 cases (37.9%: 4/10 of well-differentiated cases, 6/25 of moderately and 1/6 of poorly differentiated carcinomas). Our results confirm the possibility that HPV might play a role in the development of SqCLCs and suggest a possible relation of high-risk HPV16/18 types to tumour differentiation. [ABSTRACT FROM AUTHOR]

In a previous study a novel gene designated as US8.5 was identified in the unique short component of the herpes simplex virus type 1 (HSV1) genome. Epitope tagging experiments suggested the existence of a protein encoded by this gene in HSV1 infected cells. To further analyze the US8.5 gene product and function, a rabbit polyclonal antiserum was raised against a recombinant β-galactosidase-US8.5 fusion protein expressed in E. coli. This antiserum reacted specifically with a 19 kDa protein in HSV1(F) infected cells as shown by immunoblotting and immunoprecipitation experiments. In addition, using the same antiserum a 21 kDa protein was detected in lysates from cells infected with HSV2(G), which was most likely the HSV2 homolog of US8.5. Kinetic studies indicated that US8.5 is expressed as γ1 gene. In addition, the US8.5 protein was immunoprecipitated with the anti-US8.5 serum fromP-labeled lysates of Vero cells infected with HSV1, demonstrating that the protein is phosphorylated. Immunofluorescence studies localized the US8.5 protein to the nucleoli of HSV1 infected cells. [ABSTRACT FROM AUTHOR]