Hepatitis C quantification and sequencing in blood products, haemophiliacs, and drug users

Simmonds, Peter; Rebus, Selma; Leadbetter, G.; Peutherer, J F; Zhang, L.Q; Balfe, Peter; Ferguson, E.D; Watson, Henry G.; Ludlam, C. A.; Yap, Peng Lee

doi:10.1016/0140-6736(90)93179-s

Cited by 221 publications

(94 citation statements)

References 15 publications

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“…Crucially, this propensity for genetic change allows the virus to respond to and overcome a variety of selective pressures, including host immunity and antiviral therapy (18,26,37,44,53). HCV can be classified into six genetically distinct genotypes and further subdivided into at least 70 subtypes, which differ by approximately 30% and 15% at the nucleotide level, respectively (59,61). A significant challenge for the development of vaccines will lie in identifying protective epitopes that are conserved in the majority of viral genotypes and subtypes.…”

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confidence: 99%

Monoclonal Antibody AP33 Defines a Broadly Neutralizing Epitope on the Hepatitis C Virus E2 Envelope Glycoprotein

Owsianka

Tarr

Juttla

et al. 2005

J Virol

256

305

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Hepatitis C virus (HCV) remains a significant threat to the general health of the world's population, and there is a pressing need for the development of new treatments and preventative vaccines. Here, we describe the generation of retrovirus-based pseudoparticles (HCVpp) incorporating a panel of full-length E1E2 clones representative of the major genotypes 1 through 6, and their application to assess the reactivity and neutralizing capability of antisera and monoclonal antibodies raised against portions of the HCV E2 envelope protein.Rabbit antisera raised against either the first hypervariable region or ectodomain of E2 showed limited and strain specific neutralization. By contrast, the monoclonal antibody (MAb) AP33 demonstrated potent neutralization of infectivity against HCVpp carrying E1E2 representative of all genotypes tested. The concentration of AP33 required to achieve 50% inhibition of infection by HCVpp of diverse genotypes ranged from 0.6 to 32 g/ml. The epitope recognized by MAb AP33 is linear and highly conserved across different genotypes of HCV. Thus, identification of a broadly neutralizing antibody that recognizes a linear epitope is likely to be of significant benefit to future vaccine and therapeutic antibody development.Hepatitis C virus (HCV), a positive-strand RNA virus belonging to the Flaviviridae family, is the major cause of non-A, non-B viral hepatitis. HCV has infected approximately 200 million people worldwide and current estimates suggest that as many as 3 million individuals are newly infected each year (4). Approximately 80% of those infected fail to clear the virus; a chronic infection ensues, frequently leading to severe chronic liver disease, cirrhosis, and hepatocellular carcinoma (2, 41). Current treatments for chronic infection are ineffective for approximately 50% of patients, and there is a pressing need to develop preventative and therapeutic vaccines.Due to the error-prone nature of the RNA-dependent RNA polymerase and the high replicative rate in vivo (30, 46), HCV exhibits a high degree of genetic variability. Crucially, this propensity for genetic change allows the virus to respond to and overcome a variety of selective pressures, including host immunity and antiviral therapy (18,26,37,44,53). HCV can be classified into six genetically distinct genotypes and further subdivided into at least 70 subtypes, which differ by approximately 30% and 15% at the nucleotide level, respectively (59, 61). A significant challenge for the development of vaccines will lie in identifying protective epitopes that are conserved in the majority of viral genotypes and subtypes. This problem is compounded by the fact that the envelope proteins, the natural targets for the neutralizing response, are two of the most variable proteins (10).The envelope proteins E1 and E2 are responsible for cell binding and entry (5,8,16,51,57). They are N-linked glycosylated (23,31,43,62) transmembrane proteins with a Nterminal ectodomain and a C-terminal hydrophobic membrane anchor (12,21,22). In vitro ex...

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confidence: 99%

Monoclonal Antibody AP33 Defines a Broadly Neutralizing Epitope on the Hepatitis C Virus E2 Envelope Glycoprotein

Owsianka

Tarr

Juttla

et al. 2005

J Virol

256

305

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“…HCV RNA is usually detected in serum by sensitive polymerase chain reaction (PCR)-based techniques and has become a useful tool for diagnosis and monitoring. Besides methods for qualitative detection of viremia, a number of procedures to quantify serum HCV RNA have been developed, including end-point dilution PCR, 1 competitive PCR, 2,3 isothermal nucleic acid amplification, 4 and signal-amplification branched DNA. 5 Routine use of these techniques in a wide clinical setting is hampered by problems of specificity and sensitivity, lack of reproducibility, poor standardization, and high cost.…”

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Hepatitis C Virus Rna Profiles in Chronically Infected Individuals: Do They Relate to Disease Activity?

et al. 1999

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Fluctuations of hepatitis C virus (HCV)-RNA serum levels were monitored in a multicenter study in 76 chronic HCV carriers who had been followed longitudinally without receiving antiviral therapy to assess their relation with the course of liver disease activity. Forty-four patients had normal transaminases over more than 2 years, while 32 additional patients had fluctuating levels. Viral load was measured in serial serum samples prospectively collected for 10 to 12 months in 54 patients and in sera stored yearly up to 8 years in an additional 22 patients. In patients tested monthly, a lesser extent of fluctuations was detected in cases with constantly normal transaminases as compared with those with fluctuating transaminases. In the former group, the mean difference between maximum and minimum values observed in each individual patient was 0.7 Log, while in the latter group, it was 1.3 Log (P ‫؍‬ .0004). Most of these patients experienced, on average, three peaks of viremia over 1 year. The range of variation observed upon yearly testing was between 0.2 and 2.2 Log and did not reach statistical significance between the two groups. In conclusion, a careful viral replication profile can be achieved only by monthly testing, because longer time intervals could miss viremia fluctuations. HCV-RNA levels are more stable in asymptomatic HCV carriers than in patients with biochemical activity of liver disease. (HEPATOLOGY 1999;29: 585-589.)Chronic infection with hepatitis C virus (HCV) is characterized by persistent viremia. HCV RNA is usually detected in serum by sensitive polymerase chain reaction (PCR)-based techniques and has become a useful tool for diagnosis and monitoring. Besides methods for qualitative detection of viremia, a number of procedures to quantify serum HCV RNA have been developed, including end-point dilution PCR, 1 competitive PCR, 2,3 isothermal nucleic acid amplification, 4 and signal-amplification branched DNA. 5 Routine use of these techniques in a wide clinical setting is hampered by problems of specificity and sensitivity, lack of reproducibility, poor standardization, and high cost. 6 Recently, methods for quantitative assessment of HCV-RNA levels have become commercially available and are being extensively evaluated in clinical studies, particularly in patients treated with interferons and antivirals. 7 Little is known about viral kinetics in untreated patients, because most evaluations of the level of viremia are based on single determinations. If wide spontaneous fluctuations occur, they could mimic treatment-induced effects or lead to under-or overestimate baseline values. In a few published studies, different time intervals have been evaluated and discordant conclusions have been reported. Either trivial or consistent differences of viral load over time have been described after observation periods ranging from days to months. [8][9][10][11][12] To assess the spontaneous behavior of serum HCV-RNA levels over a reasonable length of time upon close observation, we monitored chronic HCV car...

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“…The noma. [1][2][3] Using phylogenetic analysis of the viral 5-noncoding data correlating HCV genotypes and subtypes with hep-region, a classification of HCV strains into six major types atitis C viremia levels, demographic characteristics of (HCV-1 to -6) has been introduced. Analysis of the more varipatients (age, mode of transmission, duration of infec-able coding regions of the viral genome (core, envelope, nontion), and severity of liver disease are conflicting.…”

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Phylogenetic Analysis of Hepatitis C Virus Isolates and Their Correlation to Viremia, Liver Function Tests, and Histolog

et al. 1996

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Nucleotide sequence analysis of hepatitis C virusHepatitis C virus (HCV) infection often progresses to (HCV) strains showed substantial variability leading to chronic hepatitis, cirrhosis, and possibly hepatocellular carcia classification into several genotypes and subtypes. The noma. [1][2][3] Using phylogenetic analysis of the viral 5-noncoding data correlating HCV genotypes and subtypes with hep-region, a classification of HCV strains into six major types atitis C viremia levels, demographic characteristics of (HCV-1 to -6) has been introduced. Analysis of the more varipatients (age, mode of transmission, duration of infec-able coding regions of the viral genome (core, envelope, nontion), and severity of liver disease are conflicting. The structural [NS]-3, and NS-5) indicated that major genotypes interpretation of several studies is further complicated are composed of two or more distinct subtypes, termed 1a, because the molecular methods used lacked specificity 1b, 2a etc. 4,5 The geographic distribution of HCV genomes for genotyping/subtyping and underestimated viremia differs considerably. In Europe and the United States, sublevels, especially in patients infected with HCV geno-types HCV-1a and -1b, HCV-2a and -2b, and HCV-3a are types 2 and 3. In the present study we investigated 97 most abundant, whereas in Japan HCV subtypes 1a and 3a consecutive patients with chronic hepatitis C using mo-are virtually nonexistent. Type 4 genotypes are common in lecular ''gold standard'' methods. HCV subtyping was patients from Northern Africa and the Middle East, and types performed by sequence and phylogenetic analysis of the 5 and 6 have been identified in serum samples obtained from nonstructural (NS)-5 region and serum HCV-RNA con-South Africa and Hong Kong, respectively. Sequence analysis centration was assessed by a validated genotype-inde-of HCV isolates from Vietnamese blood donors revealed addipendent quantitative reverse-transcription-polymerase tional major genetic groups (HCV-7, -8, and -9).6-8 chain reaction assay using an internal RNA standard.Several 9-12 but not all studies 13,14 have indicated a correlaPatients infected with subtypes HCV-1b, HCV-2a-c, and tion between HCV genotypes/subtypes and serum HCV-RNA HCV-4 were older than patients infected with HCV-1a concentrations. The data associating HCV genotypes/suband HCV-3a. Serum HCV-RNA levels ranged from 1.5 1 types and/or hepatitis C viremia levels with demographic, 10 4 to 1.0 1 10 8 copies/mL with no significant differences biochemical, or histological characteristics of chronically inbetween median serum HCV-RNA concentrations in pa-fected patients are conflicting. [15][16][17][18][19][20][21][22][23][24][25][26] These issues are further tients infected with different genotypes/subtypes. Al-complicated by recent evaluations showing that common gethough patients infected with HCV-1b were older, no notyping methods lack specificity 12,27 and that quantification biochemical or histological evidence was obtained that systems underestimate high virem...

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Hepatitis C quantification and sequencing in blood products, haemophiliacs, and drug users

Cited by 221 publications

References 15 publications

Monoclonal Antibody AP33 Defines a Broadly Neutralizing Epitope on the Hepatitis C Virus E2 Envelope Glycoprotein

Monoclonal Antibody AP33 Defines a Broadly Neutralizing Epitope on the Hepatitis C Virus E2 Envelope Glycoprotein

Hepatitis C Virus Rna Profiles in Chronically Infected Individuals: Do They Relate to Disease Activity?

Phylogenetic Analysis of Hepatitis C Virus Isolates and Their Correlation to Viremia, Liver Function Tests, and Histolog

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