Antibody responses against B‐cell epitopes of the hypervariable region 1 of hepatitis C virus in self‐limiting and chronic human hepatitis C followed‐up using consensus peptides

Deng

Journal of Medical Virology

et al. 2003

The hypervariable region 1 (HVR1) is the target of neutralizing antibodies but with isolate specificity. The aim of this study was to obtain immunogenic mimotopes of HVR1, which can react broadly with different HVR1 antibodies and could be one of the candidate immunogens in an effective vaccine against HCV. Thirty-one HVR1 cDNA fragments were digested by DNase I into a pool of random fragments and reassembled by repeated cycles of annealing in the presence of DNA polymerase to their original size. The shuffled HVR1 was then inserted into the gene III phagemid vector pCANTAB-5E and displayed on the surface of the phage. Eight individual phages were selected after four rounds of biopanning against anti-HVR1. ELISA was carried out on immobilized purified phages, respectively, to detect their reactivity with a panel of sera. DNA sequences of the inserts were analyzed and compared with the consensus sequences defined by Puntoriero et al. [(1998) EMBO J 17:3521-3533]. The reactivity of the eight selected clones to the 30 sera were from 53.3 to 80%. Among these, phage 13 (ETYVSGGSAARNAYGLTSLFTVGPAQK, aa 384-410) reacted most broadly. None of the selected sequences encoded for peptides corresponded to known HVR1 from original viral isolates. The two high reactive phages had the similar amino acid sequences with the consensus, which might play a particular role in determining the frequency of reactivity. In conclusion, this study has used effectively DNA shuffling combined with phage display technology to identify broadly cross-reactive mimotopes recognized by human polyclonal antibodies. Mimotope 13 and 23 appeared to be most reactive immunologically and could be candidate immunogens. Efforts are now underway to identify their neutralizing antibodies by immunization of animals.

Section: Discussionsupporting

confidence: 78%

Broadly cross‐reactive mimotope of hypervariable region 1 of hepatitis C virus derived from DNA shuffling and screened by phage display library

Deng

Journal of Medical Virology

et al. 2003

“…We found that anti-HVR1 antibodies were widely produced in chronic patients, and there was no significant difference in mild hepatitis, moderate hepatitis and liver cirrhosis. That means that the anti-HVR1 antibodies could not be used in prognostic and turnover studies of chronic HCV infection, which was coincided with other studies [14,21] .…”

Section: Discussionsupporting

confidence: 67%

Evaluation of cross-reactive antibody response to HVR1 in chronic hepatitis C

Xiu

Xia²,

He³

et al. 2010

WJG

Proc. Natl. Acad. Sci. U.S.A.

“…Because HCV does not grow robustly in cell culture, it has been difficult to demonstrate Nt Ab to the virus and, thus, to determine whether Ab protects against hepatitis C. The demonstration that both experimentally infected chimpanzees and naturally infected humans could be reinfected with HCV suggested that classical humoral immunity did not develop after resolution of hepatitis C (21-23). However, the demonstration by others that the early development of antibodies to the HCV envelope proteins, and especially to the E2 glycoprotein hypervariable region, correlated with recovery from the infection suggested that such antibodies may play a role in clearance of the virus (24)(25)(26) and that this region of the HCV envelope was under pressure from the humoral immune system. The demonstration that HCV could replicate, albeit not robustly, in certain lymphoid cells of human origin provided a means for testing for Nt Ab, and Shimizu et al (1) demonstrated that serum obtained 2 years after onset of HCV infection in a chronically infected patient could neutralize the homologous virus derived from the acute phase of infection and that serum samples obtained Ͼ5 years after infection could no longer neutralize the acute-phase virus but could neutralize variants that had emerged subsequently.…”

Section: Discussionmentioning

confidence: 99%

In vitro assay for neutralizing antibody to hepatitis C virus: Evidence for broadly conserved neutralization epitopes

Bartosch

Bukh

Meunier

et al. 2003

294

265

Our understanding of the humoral immune response to hepatitis C virus (HCV) is limited because the virus can be studied only in humans and chimpanzees and because previously described neutralization assays have not been robust or simple to perform. Nevertheless, epidemiologic and laboratory studies suggested that neutralizing Ab to HCV might be important in preventing infection. We have recently described a neutralization assay based on the neutralization of pseudotyped murine retrovirus constructs bearing HCV envelope glycoproteins on their surface. We have applied the assay to well characterized clinical samples from HCV-infected patients and chimpanzees, confirmed the existence of neutralizing Ab to HCV, and validated most previously reported neutralizations of the virus. We did not find neutralizing anti-HCV in resolving infections but did find relatively high titers (>1:320) of such Ab in chronic infections. Neutralizing Ab was directed not only to epitope(s) in the hypervariable region of the E2 envelope protein but also to one or more epitopes elsewhere in the envelope of the virus. Neutralizing Ab was broadly reactive and could neutralize pseudotype particles bearing the envelope glycoproteins of two different subgenotypes (1a and 1b). The ability to assay neutralizing anti-HCV should permit an assessment of the prospects for successful Ab-mediated passive and active immunoprophylaxis against hepatitis C. H epatitis C virus (HCV) is a small enveloped virus containing single-stranded positive sense RNA. It infects up to 170 million people worldwide and is a major cause of chronic hepatitis, cirrhosis, and hepatocellular carcinoma. Although HCV accounts for only Ϸ12% of acute hepatitis in the United States, its high rate of persistence (70-80%) makes it responsible for almost half of the economic burden of this disease.A better understanding of the pathogenesis of hepatitis C and its control is hampered by certain characteristics of the virus. (i) HCV is genetically and probably serologically heterogeneous.(ii) The only animal model for HCV infection is the chimpanzee. (iii) Although the virus replicates sparingly in some cell lines, the in vitro method developed for detecting neutralizing antibodies (Nt Ab) to HCV in this system is so difficult to perform that it has not been widely used. Consequently, although the two envelope proteins of HCV, E1 and E2, have been expressed individually and as heterodimers, and Ab to them has been measured, there is no confirmation that such Ab accurately reflects the response to the virus or that it is Nt Ab.Previously, we identified Nt Ab to HCV by their ability to prevent replication of the virus in a lymphoid cell line (1, 2) or to prevent hepatitis C in chimpanzees (3, 4). These and a small number of similar studies (5) have provided, for almost a decade, the only direct evidence for Ab-mediated neutralization of HCV. Consequently, although considerable new knowledge has been gained about the cellular immune response to HCV, little is known about the role of the hum...