HCV Type Research Articles

Flow cytometric detection of hepatitis C virus antigens in infected peripheral blood leukocytes: binding and entry.

We designed two synthetic-core-specific peptides core 1 (C1) and core 2 (C2), and an E1-specific peptide (E1). We produced specific polyclonal antibodies against these peptides and used the antibodies for detection of HCV antigens on surface and within infected peripheral blood leukocytes. Peripheral blood from a healthy individual who tested negative for HCV RNA was incubated with HCV type 4 infected serum for 1 h and 24 h at 37 degrees C. Cells were stained by direct and indirect immunofluorescence and measured by flow cytometry. After 1 h of incubation, antibodies against C1, C2, and E1 detected HCV antigens on the surface of 27%, 26% and 73% of monocytes respectively, while 10%, 5% and 9% of lymphocytes were positive with anti-C1, anti-C2 and anti-E1 respectively. Only 1-3% of granulocytes showed positive staining with anti-C1, anti-C2 and anti E1 antibodies. After 24 h of incubation, we found no surface staining with anti-C1, anti-C2 or anti-E1. Direct immunostaining using anti-C2 could not detect intracellular HCV antigens, after 1 h of incubation with the virus, while after 24 h of incubation, 28% of infected cells showed positive staining. Only plus strand RNA was detectable intracellularly as early as 1 h after incubation, and remained detectable throughout 48 h post-infection. Interestingly, minus RNA strand could not be detected after 1 h, but became strongly detectable intracellularly after 24 h post-infection. Monocytes and lymphocytes are the preferred target cells for HCV infection in peripheral blood leukocytes. Our specific anti-core and anti-E1 antibodies are valuable reagents for demonstration of HCV cell cycle. Also, HCV is capable of infecting and replicating in peripheral blood mononuclear cells as confirmed by detection of minus strand HCV RNA as well as intracellular staining of core HCV antigen.

The RNA-Unwinding Activity of Hepatitis C Virus Non-Structural Protein 3 (NS3) Is Positively Modulated by Its Protease Domain

The nonstructural protein 3 (NS3) of hepatitis C virus contains a protease domain at its amino terminus and RNA helicase domain at its carboxyl terminus. To identify optimal NS3 protein for developing screening assays, we expressed full-length NS3 protease/helicase and helicase domains from both HCV type 1a (H77 strain) and 1b (Con1 strain), using either E. coli or baculovirus expression systems. Our studies showed that the full-length NS3 proteins, either with or without the presence of the NS4A domain, from either strains were at least 10-fold more efficient than the corresponding helicase domains in unwinding partial duplex RNA substrates. These findings provide a rationale for the use of full-length NS3 in high throughput screening assays to identify potent small molecule inhibitors of this important target of HCV.

618 Influence of apolipoprotein E4 allele (APO E4) on viral dynamics and early response rate in HCV type 1-infected patients treated with PEG-IFNα and ribavirin

618 Influence of apolipoprotein E4 allele (APO E4) on viral dynamics and early response rate in HCV type 1-infected patients treated with PEG-IFNα and ribavirin

Viral evolution and interferon resistance of hepatitis C virus RNA replication in a cell culture model.

Hepatitis C virus (HCV) replicates through an error-prone process that may support the evolution of genetic variants resistant to the host cell antiviral response and interferon (IFN)-based therapy. We evaluated HCV-IFN interactions within a long-term culture system of Huh7 cell lines harboring different variants of an HCV type 1b subgenomic RNA replicon that differed at only two sites within the NS5A-encoding region. A replicon with a K insertion at HCV codon 2040 replicated efficiently and exhibited sequence stability in the absence of host antiviral pressure. In contrast, a replicon with an L2198S point mutation replicated poorly and triggered a cellular response characterized by IFN-beta production and low-level IFN-stimulated gene (ISG) expression. When maintained in long term-culture, the L2198S RNA evolved into a stable high-passage (HP) variant with six additional point mutations throughout the HCV protein-encoding region that enhanced viral replication. The HP RNA transduced Huh7 cells with more than 1,000-fold greater efficiency than its L2198S progenitor or the K2040 sequence. Replication of the HP RNA resisted suppression by IFN-alpha treatment and was associated with virus-directed reduction in host cell expression of ISG56, an antagonist of HCV RNA translation. Accordingly, the HP RNA was retained within polyribosome complexes in vivo that were refractory to IFN-induced disassembly. These results identify ISG56 as a translational control effector of the host response to HCV and provide direct evidence to link this response to viral sequence evolution, ISG regulation, and selection of the IFN-resistant viral phenotype.

EXPRESSION AND HUMORAL IMMUNE RESPONSE TO HEPATITIS C VIRUS USING A PLASMID DNA CONSTRUCT

Purpose: The objective of this study was to clone a c-DNA fragment of hepatitis C virus in a eukaryotic expression vector and to measure the efficacy of humoral immune responses in mice inoculated with this recombinant plasmid. This study was an attempt to lay a foundation for HCV nucleic acid vaccine development in the future. Methods: A c-DNA fragment of BK146, a clone of HCV type 1b, was sub-cloned into an eukaryotic expression vector pMT3. HepG2 and COS cells were transfected with this construct, named pMT3-BK146. The expression of HCV mRNA and proteins was studied by reverse transcribed polymerase chain reaction, radio Immunoprecipitation (RIPA) and immunofluorescence (IFA). The DNA of this construct was injected into the footpad of BALB/c mice and antibody response was tested by enzyme immunoassay and indirect immunofluorescence. Results: COS and HepG2 cells transiently transfected with the recombinant plasmid pMT3-BK146 showed the expression of HCV proteins by RT-PCR, RIPA and immunofluorescence. This DNA clone when injected into Balb/c mice was able to generate specific antibody response to hepatitis C virus by ELISA and IFA. Conclusions: A c-DNA fragment of HCV cloned in an eukaryotic expression vector was able to express core protein. This DNA clone was also able to elicit antibody response in mice. This can be an initial step towards the development of a potential DNA vaccine for hepatitis C virus infection.

Multiple infections with different HCV genotypes: prevalence and clinical impact.

In a HCV genotype 3a-infected patient, viremia with a different genotype (1b) was detected after 16 weeks of ineffective therapy. Serological typing revealed that this genotype had already been present prior to therapy. To investigate the epidemiology of multiple HCV infections and the therapeutical consequences for patients superinfected with a new HCV strain. Sera of 600 patients were screened for infection with multiple genotypes by using sequencing and a serological assay in parallel. Infection with two different HCV types was detected in 13 patients. The prevailing strain was genotyped by sequencing. From two of these patients additional sera were available which had been drawn up to 24 and 28 months prior to the current sample, respectively. Those early samples showed viremia with a HCV subtype that could not be detected by PCR afterwards. Only antibodies to the initial strain were detectable in the later samples. In patients serially infected by different HCV strains, one strain will prevail as the viremic virus. Under antiviral therapy, the displaced strain may become viremic again and may influence the outcome of therapy. Detection of inferior strains by serological assays before antiviral therapy may be important for choosing the adequate regimen.

Dynamics of viral quasispecies during interferon therapy in non responder chronic hepatitis C patients

the reference method to study the HCV complexity was cloning and sequence analysis of a sufficient number of clones. The evolution of the viral complexity in chronic non responder patients during treatment with standard doses of interferon was not very well investigate because this method was expensive and labour intensive when large series of patients were concerned. Meanwhile, with the alternative Single-Strand Conformation Polymorphism (SSCP) method, a rough estimation of the quasispecies present in a given sample could be obtained. the aim of the study was to analyse the evolution of HCV heterogeneity, investigated by SSCP analysis targeted to the HVR-1, in 30 nonresponders chronic hepatitis C patients treated by Interferon-alpha 3MUI. genotype 1 was the main HCV type found in this population (77% of non responder patients). Before treatment, the SSCP assay revealed a high complexity pattern: the median of SSCP band number was 9. During IFN-alpha treatment, SSCP band number didn't change. However a significant decrease of the viral load was observed (P<0.01). Patients with variations in their SSCP patterns after therapy significantly decreased HCV RNA levels (P<0.002). In one third of patients the SSCP profile didn't change at all. we observed that viral heterogeneity didn't change in non responder chronic hepatitis C patients during IFN-alpha treatment. Nevertheless patients with a low number of pre-treatment quasispecies exhibited an improvement of the response (P<0.02). These phenomena were probably due to a selection of resistant variants present prior onset of therapy.

Clinical implications of HCV quasispecies heterogeneity in patients with hepatitis C

To determine the heterogeneity of viral quasispecies and its clinical significance in patients with hepatitis C. Quasispecies in the sera from 76 patients infected with hepatitis C virus were detected using single stranded conformational polymorphism (SSCP) analysis of the HCV E2 hypervariable region 1 (HVR1). HVR1 was amplified in 72 (94.7%) of the 76 patients. The average number of SSCP bands was 5.8, with a range from 2 to 11. The numbers of quasispecies in acute hepatitis, chronic hepatitis and liver cirrhosis and/or primary hepatocellular carcinoma were 3.1 +/- 1.2, 6.0 +/- 2.3 and 8.4 +/- 4.1, respectively. There was a statistically significant difference among them (P < 0.01). Patients with infection acquired by blood transfusion and i.v. drug use had greater number of quasispecies than those acquired by other transmission pathway (sporadic) (P < 0.05). Patients with genotype 1 a and 1 b infection had increased quasispecies compared with those infected with HCV type 2 and 3(P < 0.05). Increased quasispecies heterogeneity was significantly correlated with serum HCV RNA levels (P < 0.01). SSCP is a simple, rapid and reliable method for the analysis of HCV viral quasispecies heterogeneity. Quasispecies heterogeneity plays an important role in HCV persistent infection and in the progress of hepatitis C. The duration of HCV infection, HCV genotype and HCV viremia are important determinants for the evolution of HCV quasispecies heterogeneity.

IFN alpha 2B and ribavirin in naive patients with HCV type 1 chronic hepatitis: results after 6 months of therapy

IFN alpha 2B and ribavirin in naive patients with HCV type 1 chronic hepatitis: results after 6 months of therapy

IFN alpha 2b and ribavirin in naive patients with HCV type 1 chronic hepatitis: results after 6 months of therapy

IFN alpha 2b and ribavirin in naive patients with HCV type 1 chronic hepatitis: results after 6 months of therapy

Characteristics and course of small hepatocellular carcinomas in patients with hepatitis C virus types 1 and 2

The associations between types of HCV and tumor characteristics and recurrence and survival after treatment of small HCC were investigated. Viral genotype-specific antibodies were measured in sera obtained at the time of diagnosis of HCC, in 92 patients with HCC ≤ 2 cm in diameter who were treated between 1990 and 1998. The degrees of tumor differentiation and angiographically-evaluated hypervascularity were compared between patients infected with HCV type 1 and those with type 2. Survival, time to recurrence, and patterns of recurrence after initial treatment also were compared. On pathologic evaluation, 6 of 21 HCC (28.6%) in patients with HCV type 2 were well-differentiated, whereas 28 of 48 HCC (58.3%) in patients with HCV type 1 were well-differentiated (P = 0.0229). HCC in patients with HCV type 2 showed hypervascularity more frequently than HCC in patients with HCV type 1, with tumor staining evident by digital subtraction arteriography in 17 of 22 patients with HCV type 2 (77.3%) vs. 20 of 50 in patients with HCV type 1 (40.0%, P = 0.0036). Survival and overall recurrence rates were similar in patients infected with HCV type 1 and with HCV type 2 (P = 0.5537). In the analyses of patterns of recurrence, recurrences in patients infected with HCV type 2 were relatively more likely to be intrahepatic metastases (P = 0.0342), that was closely related to the differentiation of HCC. Multicentric occurrence of HCC was a more frequent type of recurrence in patients with HCV type 1 (P = 0.1619), and infection of HCV type 1 was an independent factor for multicentric occurrence in multivariate analysis (P = 0.0021). In HCC ≤ 2 cm in diameter, HCV type 2 is associated with more progression of HCC than HCV type 1, whereas patients with HCV type 1 may be at higher risk for multicentric HCC occurrence after the treatment of HCC. J. Med. Virol. 63:120–127, 2001. © 2001 Wiley-Liss, Inc.

Characteristics and course of small hepatocellular carcinomas in patients with hepatitis C virus types 1 and 2

The associations between types of HCV and tumor characteristics and recurrence and survival after treatment of small HCC were investigated. Viral genotype-specific antibodies were measured in sera obtained at the time of diagnosis of HCC, in 92 patients with HCC < or = 2 cm in diameter who were treated between 1990 and 1998. The degrees of tumor differentiation and angiographically-evaluated hypervascularity were compared between patients infected with HCV type 1 and those with type 2. Survival, time to recurrence, and patterns of recurrence after initial treatment also were compared. On pathologic evaluation, 6 of 21 HCC (28.6%) in patients with HCV type 2 were well-differentiated, whereas 28 of 48 HCC (58.3%) in patients with HCV type 1 were well-differentiated (P = 0.0229). HCC in patients with HCV type 2 showed hypervascularity more frequently than HCC in patients with HCV type 1, with tumor staining evident by digital subtraction arteriography in 17 of 22 patients with HCV type 2 (77.3%) vs. 20 of 50 in patients with HCV type 1 (40.0%, P = 0.0036). Survival and overall recurrence rates were similar in patients infected with HCV type 1 and with HCV type 2 (P = 0.5537). In the analyses of patterns of recurrence, recurrences in patients infected with HCV type 2 were relatively more likely to be intrahepatic metastases (P = 0.0342), that was closely related to the differentiation of HCC. Multicentric occurrence of HCC was a more frequent type of recurrence in patients with HCV type 1 (P = 0.1619), and infection of HCV type 1 was an independent factor for multicentric occurrence in multivariate analysis (P = 0.0021). In HCC < or = 2 cm in diameter, HCV type 2 is associated with more progression of HCC than HCV type 1, whereas patients with HCV type 1 may be at higher risk for multicentric HCC occurrence after the treatment of HCC.

Quantitation of HCV RNA in liver of patients with chronic hepatitis C

Liver HCV RNA has been quantitated in few studies and the feasibility and the role of this parameter in the evaluation of patients with chronic HCV hepatitis still warrant study. Our aim was to determine the concentrations of HCV RNA in the liver of chronic HCV patients and to correlate the results with serum viral load. We also studied the relation of levels of HCV RNA in the liver with serum aminotransferases levels and with the presence of cirrhosis. Twenty patients (14 males, aged 28 to 61 years) were studied. Twelve were infected by HCV type 1, six by type 3 and one by type 5. Percutaneous liver biopsy samples were obtained from 14 patients, and the remainder from liver explant in patients undergoing OLT. Twelve had chronic hepatitis and eight cirrhosis. HCV RNA levels were determined by bDNA. HCV RNA levels below the detection limit were found in one liver and in five serum samples. HCV RNA (mean +/- SD) was 2.1 x 10(8) +/- 2.2 x 10(8) Eq/gm in the liver and 94 x 10(5) +/- 93 x 10(5) Eq/mL in serum, with a significant correlation between these values (r = 0.89; P < 0.0001). Serum HCV RNA levels were significantly lower (P = 0.001) in cirrhotic than in chronic hepatitis patients, while the groups did not differ in liver HCV RNA levels. No correlation was observed between liver or serum HCV RNA and serum ALT or AST. Quantitation of HCV RNA is possible even in small liver samples. Although average levels are more than one log higher than those observed in serum, hepatic concentrations correlate with those observed in serum. The application of this technology to monitoring antiviral therapy and understanding the pathogenesis of the disease remains to be determined.

Molecular analysis of HCV type 1 to 5 envelope gene: application to investigations of posttransfusion transmission of HCV.

Until 1990, HCV infection was common in transfused patients, resulting in more than 200,000 cases of posttransfusion hepatitis C in France alone. A molecular method that permits the investigation of posttransfusion hepatitis C infections is presented. Viral sequences in the envelope region of HCV were obtained for 12 pairs of blood recipients and their respective blood donors. The HCV strains studied belonged to types 1 (subtypes 1a and 1b), 2, 3, 4, and 5. Genetic distances and mutation rates were determined, and sequences were submitted to phylogenetic analysis along with sequences retrieved from nucleotide databases. Pairwise distances in the donor-recipient pairs were found to be less than 0.05 mutation per site, which corresponds to a mutation rate ranging from 0.6 x 10(-3) to 2.1 x 10(-3) per site per year. Sequences obtained from the 12 donor-recipient pairs clustered in 12 monophyletic nests. The genetic analysis of the envelope region of HCV can be used for the forensic evaluation of virus transmission. It permits the refutation of a link between blood transfusion and HCV transmission, rather than proof of the existence of such a link.

Relationship between genotypes of hepatitis C virus and histopathological manifestations in chronic hepatitis C patients.

The aim of this study was to assess the relationship between HCV genotype and histological liver injury. Prospective study on a cohort of patients with biopsy proven chronic hepatitis C. University medical centre. Enrolled were 324 consecutive patients (male 197, median age 52 years, range 19-68; chronic hepatitis, 224; cirrhosis, 100). HCV genotype was determined by the INNO LiPA assay and HCV RNA levels by the bDNA assay. The histological features were scored according to the histology activity index. The distribution of HCV genotypes was 1a, 4.6%; 1b, 52.4%; 2a/c, 27%; 3a, 8%; 4, 2%; mixed, 6%. Serum HCV RNA levels were similar for all genotypes. There was no difference in the distribution of HCV genotypes between patients with chronic hepatitis and those with cirrhosis. Patients with genotype 1b and those with type 2a/c showed a similar prevalence of cases of cirrhosis (33% versus 31%, respectively). In addition, in a subgroup of 102 patients with an established date of infection, the progression to cirrhosis occurred with a similar length of time for HCV type 1b and 2a/c (median 16 versus 15 years, respectively). Patients with HCV genotype 2a/c or mixed genotype showed a higher histology activity index than those with type 1b (P< 0.01), whereas there was no difference in the fibrosis score for the different genotypes. Patients with genotype 3a showed a significantly higher prevalence of steatosis compared to those infected with other genotypes. Alanine aminotransferase (ALT) values were higher in patients with HCV type 2a/c, 3a and mixed genotype than those with type 1 (P < 0.002). The data indicate that there is no association between a particular HCV genotype and the progression to cirrhosis, and that specific genotypes are associated with distinct histopathological and biochemical manifestations although none of them is correlated with an increase of the fibrosis stage.

Correlation of genotypes and route of transmission with histologic activity and disease stage in chronic hepatitis C.

Our objective was to evaluate the histopathological features of chronic hepatitis C of 64 liver biopsies and to correlate this with the route of transmission of hepatitis C virus, the genotype of HCV, and the patient's age. Moderate chronic hepatitis was the most frequently observed (62.5%). Cirrhosis was observed in 14 patients (21.9%) and was more frequently found among patients over 40 years of age (34.3% vs. 6.9%, P = 0.025). The mean histopathological activity index (HAI) was significantly higher in the sporadic (10+/-3.1) than the posttransfusional (7.5+/-3.7) and the intravenous drug use (IVDU) groups (6.3+/-2.8) (P<0.02). Moreover the sporadic group showed more fibrosis (P<0.04) than the posttransfusional group. No liver cirrhosis was found in the IVDU group. The overall prevalence of HCV variants was: 54.7% type 1b, 4.6% type 1a, 37.5% type 2c, 1.6% type 2b, 1.6% type 2. The genotype distribution showed no relation to the HAI, hepatitis activity (grade), and fibrosis (stage) of the liver disease. In conclusion, the sporadic route of transmission of HCV was related to a more severe chronic hepatic disease, a finding that could influence future antiviral therapies. The predominance of HCV type 1b in this study reflects the higher frequency of this variant in our area. Our data suggests that the ultimate consequence of HCV chronic infection depends on patient age rather than on HCV genotype.

Steatosis is a determinant of fibrosis progression in chronic hepatitis C and is correlated both with body composition and viral factors

The knowledge of factors which induced progression of chronic hepatitis C (CHC) is of pr ima~ importance for cfinical, prognostic and therapeutic implications. The aim of this study was to evaluate the role of steatosis in the progression of liver fibrosis. 180 (median age, 49 yrs) consecutive untreated patients with biopsy-proven CHC and stable weight were enrolled. Excluded were patients with diabetes, dydipidemie, alcohol intake >30 g/d, genetic or antoimmune hepatic diseases, or HBV or HIV. Patients were evaluated for histological grading, staging, grading of steatosis (0-4) and hepatic ken, HCV genotype (InnoLipa), levels of viremia CoDNA), body mass index (BMI), waist circumference. O v e r ~ prevalence of steatosis was 41%. HCV genotypes were not correlated with fibrosis. Steatosis was more frequent in patients with genotype 3a (p 40% showed a higher HAI (6.2 vs 5.0; p<0.01), levels of yGT (p<0.0001) and ALT values (p<0.01). In conclusion our study indicates that steatosis is a determinant of fibrosis progression in CHC. Visceral obesity plays a role in the development of steatosis. HCV type 3a seems to have s direct effect on steatogenesis. (Supported by MURST). l P/C06/47 l

Molecular epidemiology of hepatitis C virus infection in an area of hyperendemicity in southern Italy: a population-based study.

In a cohort of subjects from Italy, anti-hepatitis C virus (HCV) and HCV RNA [HCV(+) subgroup] prevalences were 24.6 and 79.6%, respectively. HCV types 1b and 2a/c accounted for 95% of infections. Adjusted alanine aminotransferase levels were higher in males than in females and in RNA-positive subjects than in RNA-negative subjects regardless of HCV type. Genotype distribution was unrelated to demographic variables.

Hepatitis C virus serotypes and sources of infection in patients with HCV-related chronic liver disease from one geographical area in southeast Italy.

Hepatitis C virus serotypes and sources of infection in HCV-positive patients from a restricted geographical area were evaluated. HCV serotypes were determined by Murex serotyping assay. Of 192 samples, serotypes were detected in 189 (98.5%): type 1 proved to be the most common (53.1%), followed by types 2 (15.2%), 3 (6.2%), 6 (5.3%), 4 (3.6%) and 5 (1.6%). Intravenous drug users were significantly younger than the rest of the patients and infected mainly with HCV type 3. Transmission of HCV 3 has only been observed over the past 20 years; other types have been transmitted for up to 40 years. These results support the view that the prevalence of the infection by different HCV types in one restricted geographical area may be associated with the source and duration of infection.

Predominance of HCV type 2a in saliva from intravenous drug users.

Paired serum and saliva samples were collected simultaneously from 50 intravenous drug users with serologically proven hepatitis C virus infection. The oral health of the volunteers was also assessed. Hepatitis C virus RNA was detected by nested PCR, employing primers from the 5' noncoding region. Positive PCR products were sequenced using the Sequenase PCR Product Sequencing Kit (Amersham Life Sciences). HCV RNA was detected in 33 (66%) of the 50 serum samples. HCV RNA was detected in 19 (57.6%) of the corresponding 33 saliva samples. There was no correlation between oral health status or HIV seropositivity and the detection of HCV in saliva. However, subjects with HCV in their saliva were significantly more likely to complain of xerostomia (P < 0.05). Isolate genotypes were identified in paired serum and saliva of 15 intravenous drug users. HCV genotypes 1, 2, 3 and 6 were detected in both specimens. In seven cases, a differing HCV genotype was found in serum compared to the paired saliva specimen. The distributions of genotypes in serum and saliva were very different, with genotype 2a more common in saliva than serum (P < 0.005). These data suggest that in some cases the source of salivary HCV may not be serum transudation along the periodontal membrane or across damaged mucosa, and that an alternative local source, possibly the salivary glands themselves, should be considered.