scholarly journals Immunity in Chimpanzees Chronically Infected with Hepatitis C Virus: Role of Minor Quasispecies in Reinfection

1998 ◽  
Vol 72 (3) ◽  
pp. 1725-1730 ◽  
Author(s):  
Colby A. Wyatt ◽  
Linda Andrus ◽  
Betsy Brotman ◽  
Fannie Huang ◽  
Dong-Hun Lee ◽  
...  

ABSTRACT We have previously reported that chimpanzees chronically infected with hepatitis C virus (HCV) could be reinfected, even with the original infecting strain. In this study we tested the hypothesis that this might reflect the presence of minor quasispecies to which there was little or no immunity. To evaluate this hypothesis, we sequenced multiple clones taken at intervals after primary infection and rechallenge from four chronically infected chimpanzees. The inoculum used in these studies (HCV-H, genotype 1a) revealed 17 separate variants among 46 clones sequenced. Following challenge, each of the four challenged animals showed marked alterations of their quasispecies distribution. The new variants, which appeared 1 to 6 weeks after challenge, were either identical to or closely resembled variants present in the challenge inoculum. These results, paralleled by an increase in viremia in some of the challenged animals, suggest that quasispecies in the challenge inoculum were responsible for signs of reinfection and that there was little immunity. However, the newly emerged quasispecies completely took over infection in only one animal. In the remaining three chimpanzees the prechallenge quasispecies were able to persist. The natural evolution of infection within chimpanzees resulted in variants able to compete with the inoculum variants. Whether through reexposure or the natural progression of infection, newly emerged quasispecies are likely to play a role in the pathogenesis of chronic HCV infection.

2016 ◽  
Vol 10 (1) ◽  
pp. 37-41
Author(s):  
Fatima Abood Chaloob

Infection with hepatitis C virus (HCV) imposes a global challenge with over 180 million cases worldwide. Only few patients spontaneously had their virus neutralized, while most patients develop chronic HCV infection. This implies a key role of genetic factors in viral clearance or persistence. The current study aimed at clarifying the effect of certain single nucleotide polymorphisms (SNPs) on individual's susceptibility to HCV infection.  A total of 60 patients with confirmed HCV infection and 35 apparently healthy individuals were enrolled in this study. Blood sample was obtained from each participant, from which DNA was extracted. The JAK1gene was amplified with conventional PCR technique using three sets of primers targeting three SNPs in this gene: rs2780895, rs4244165 and rs17127024. Restriction fragment length polymorphism (RFLP) was used for genotyping of PCR products. Each of rs2780895 and rs17127024 had two genotypes in both patients and controls, however, only the heterozygous genotype of the SNP rs2780895 (CT) significantly associated with the susceptibility to HCV. The SNP rs4244165 appeared in only with homozygous wild genotype (GG) in both patients and controls. It can be concluded that allele T of the SNP rs2780895 could be considered as a risk factor for infection with HCV


1994 ◽  
Vol 39 (9) ◽  
pp. 2022-2031 ◽  
Author(s):  
Shinjiro Sato ◽  
Shigetoshi Fujiyama ◽  
Motohiko Tanaka ◽  
Masafumi Goto ◽  
Yuko Taura ◽  
...  

2001 ◽  
Vol 45 (2) ◽  
pp. 517-524 ◽  
Author(s):  
Jeffrey M. Jacobson ◽  
Lawrence Feinman ◽  
Leonard Liebes ◽  
Nancy Ostrow ◽  
Victoria Koslowski ◽  
...  

ABSTRACT Hypericin is a natural derivative of the common St. Johns wort plant, Hypericum perforatum. It has in vitro activity against several viruses, including bovine diarrhea virus, a pestivirus with structural similarities to hepatitis C virus (HCV). We conducted a phase I dose escalation study to determine the safety and antiviral activity of hypericin in patients with chronic HCV infection. The first 12 patients received an 8-week course of 0.05 mg of hypericin per kg of body weight orally once a day; 7 patients received an 8-week course of 0.10 mg/kg orally once a day. At the end of the 8-week period of treatment, no subject had a change of plasma HCV RNA level of more than 1.0 log10. Five of 12 subjects receiving the 0.05-mg/kg/day dosing schedule and 6 of 7 subjects receiving the 0.10-mg/kg/day dosing schedule developed phototoxic reactions. No other serious adverse events associated with hypericin use occurred. The pharmacokinetic data revealed a long elimination half-life (mean values of 36.1 and 33.8 h, respectively, for the doses of 0.05 and 0.1 mg/kg) and mean area under the curve determinations of 1.5 and 3.1 μg/ml × hr, respectively. In sum, hypericin given orally in doses of 0.05 and 0.10 mg/kg/d caused considerable phototoxicity and had no detectable anti-HCV activity in patients with chronic HCV infection.


2006 ◽  
Vol 80 (15) ◽  
pp. 7364-7374 ◽  
Author(s):  
Kyung-Soo Chang ◽  
Zhaohui Cai ◽  
Chen Zhang ◽  
Ganes C. Sen ◽  
Bryan R. G. Williams ◽  
...  

ABSTRACT Hepatitis C virus (HCV) infection causes chronic hepatitis and is currently treated with alpha interferon (IFN-α)-based therapies. The underlying mechanisms of chronic HCV infection and IFN-based therapies, however, have not been defined. Protein kinase R (PKR) was implicated in the control of HCV replication and mediation of IFN-induced antiviral response. In this report, we demonstrate that a subgenomic RNA replicon of genotype 2a HCV replicated efficiently in mouse embryonic fibroblasts (MEFs), as determined by cell colony formation efficiency and the detection of HCV proteins and both positive- and negative-strand RNAs. Additionally, the subgenomic HCV RNA was found to replicate more efficiently in the PKR knockout (PKR−/−) MEF than in the wild-type (PKR+/+) MEF. The knockdown expression of PKR by specific small interfering RNAs significantly enhanced the level of HCV RNA replication, suggesting that PKR is involved in the control of HCV RNA replication. The level of ISG56 (p56) was induced by HCV RNA replication, indicating the activation of PKR-independent antiviral pathways. Furthermore, IFN-α/β inhibited HCV RNA replication in PKR−/− MEFs as efficiently as in PKR+/+ MEFs. These findings demonstrate that PKR-independent antiviral pathways play important roles in controlling HCV replication and mediating IFN-induced antiviral effect. Our findings also provide a foundation for the development of transgenic mouse models of HCV replication and set a stage to further define the roles of cellular genes in the establishment of chronic HCV infection and the mediation of intracellular innate antiviral response by using MEFs derived from diverse gene knockout animals.


1996 ◽  
Vol 60 (2) ◽  
pp. 179-182 ◽  
Author(s):  
Francesco Negro ◽  
Hugo Troonen ◽  
Gerd Michel ◽  
Emiliano Giostra ◽  
Monika Albrecht ◽  
...  

2008 ◽  
Vol 13 (21) ◽  
Author(s):  
W L Irving ◽  
D Salmon ◽  
C Boucher ◽  
I M Hoepelman

Around 25% of people infected with hepatitis C virus (HCV) are able to clear the infection spontaneously, while the majority become chronically infected, with a subsequent risk for the individual patient of progressive inflammatory liver disease, cirrhosis, hepatocellular carcinoma and liver-related death (Figure 1). Much is known about the epidemiology, pathogenesis, diagnosis and management of chronic HCV infection. In comparison, knowledge about acute HCV infection is patchy. In this article, we will highlight concerns relating to acute HCV infection and suggest that public health bodies responsible for managing the HCV epidemic should redirect at least some of their resources to dealing with these issues.


2006 ◽  
Vol 59 (5-6) ◽  
pp. 230-234 ◽  
Author(s):  
Dragan Delic ◽  
Zorica Nesic ◽  
Jasmina Simonovic ◽  
Neda Svirtlih ◽  
Ljubisa Dokic ◽  
...  

Introduction. Hepatitis C virus (HCV) RNA status and HCV genotypes have become extremely important for exact diagnosis, prognosis, duration of treatment and monitoring of antiviral therapy of chronic HCV infection. Material and methods. For the purpose of precise and objective assessment of virologic analyses, such as the determination of the number of virus copies and virus genotypes, 110 patients with chronic HCV infection were tested. Genotyping of HCV isolates and HCV RNA quantification were performed by using the PCR method. Genotype lb infection was verified in 49.1% of patients, genotype 3a infection was found in 28.2%, genotype 4 in 9.1%, genotype 2 in 4.5%, while mixed genotype infections were diagnosed in 9.1% of cases. Results. Patients infected by genotype lb had significantly higher serum HCV RNA level in relation to patients infected by other genotypes (p<0.05). Over 70% of patients infected by genotype lb had more than 2xl06 virus copies in 1 ml of blood, while in genotypes 2, 3a and 4, the percentage was 40%, 38.5% and 30%, respectively. Male patients had approximately 7.7x10.6 virus copies in 1 ml of blood, which was significantly higher in comparison with female patients (2.3xl06 copies/ml; p<0.05). Conclusion. Our results are in concordance with the results of other authors reporting that genotype lb is predominant in Europe, as well as significantly higher incidence of viremia in patients with genotype lb infection in relation to other HCV genotypes. Based on these results, we can conclude that our patients, most commonly, present with severe clinical course of chronic HCV infection and require longer treatment (48 weeks), which causes economic problems. .


2015 ◽  
Vol 4 (1) ◽  
pp. 32-35
Author(s):  
Dipesh Gurubacharya ◽  
Mohan Khadka ◽  
Khadga B Shreshta ◽  
Prem Khadga ◽  
Sashi Sharma

Introduction: Hepatitis C virus (HCV) infection is a major public health challenge. It is a major cause for cirrhosis and hepatocellular carcinoma worldwide. Both the genotype and viral load of HCV determine the choice of therapy as well as outcome of therapy. The aim of this study was to evaluate clinical, biochemical and virological profile and association of HCV genotypes with viral load and liver biochemical profile.Material and Methods: This was descriptive observational study of chronic HCV infected patients who attended at the outpatient clinic of Department of Gastroenterology of TUTH, IOM from April 2013 to November 2014. During this study period 38 patients with chronic HCV infection were analyzed. Clinical profile, possible risk factors for transmission of HCV infection and liver biochemical profile were recorded. Virological profile included HCV viral load and HCV genotypes.Results: Out of 38 patients 34(89.5%) were male and 4(10.5%) were female. Injection drug use (IDU) was the most common mode for acquisition of HCV infection (55.3%). Genotype 3 was found in 21(55.26%) patients and genotype 1 was found in 17(44.74%) patients. There was no significant association between HCV genotypes and serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) level. And also there was no significant association between HCV viral load and different HCV genotypes.Conclusions: In our study HCV genotype 3 was the most prevalent genotype in patients with chronic HCV infection. Injection drug use was identified as most common identifiable risk factor for transmission of HCV infection. There was no significant association between different HCV genotypes and serum ALT, AST level and HCV viral load. Journal of Nobel College of Medicine Vol.4(1) 2015: 32-35


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