Quantitative analysis of antibody to hepatitis C virus envelope 2 glycoprotein in patients with chronic hepatitis C virus infection

Abstract

The significance of circulating antibody to hepatitis C HCV E1 corresponds to the pestiviral gp33/gp25 envevirus (HCV) envelope glycoprotein 2 (E2)/nonstructural lope glycoprotein and the flaviviral envelope protein protein 1 (NS1) glycoprotein was studied in 83 patients (M/E), whereas E2/NS1 corresponds to the pestiviral with chronic HCV infection diagnosed by polymerase gp53/gp55 envelope glycoprotein and the flaviviral chain reaction (PCR). E2/NS1 antibody was quantita-NS1. 1 Based on the greater homology between HCV tively examined by a passive hemagglutination test us-and the pestiviruses 1,4-6 and the absence of HCV E2/ ing recombinant E2/NS1 glycoprotein encompassing NS1 secretion into the medium by transfected mammaamino acids 388 to 664 of the HCV-H strain. The results lian Chinese hamster ovary cells, it has been proposed were correlated with clinical and virological features such as genotypes and viremic levels assessed by a com-that E2/NS1 more likely represents a virion envelope petitive reverse-transcription PCR assay. E2/NS1 anti-glycoprotein than the secreted NS1 of the flaviviruses. body was found in 73 patients (88%), and its occurrence Both the pestiviral gp53/gp55 and flaviviral NS1 glycowas related to viremic levels. E2/NS1 antibody titers proteins are known to elicit protective antibodies in were low in asymptomatic HCV carriers with low levels hosts. 7,8 HCV envelope glycoproteins can be considered of viral replication; 9 of 17 such patients tested positive possible candidates for vaccination against HCV infecfor E2/NS1 antibody (53%), compared with 64 of 66 tion. 9 However, the implications of the E2/NS1 antichronic hepatitis C patients (97%) (P õ .01). A significant direct relationship was observed between viremic levels body response in chronic HCV infection are not fully and E2/NS1 antibody titers (r Å .52, P õ .01). Of the 13 understood.patients with low viremic levels of õ10 6 copies/mL, only

Persistent Infection Mechanism of GB Virus C/Hepatitis G Virus Differs from That of Hepatitis C Virus

“…Kato et al [22] analyzed the heterogeneity of GBV-C/HGV by single-strand conformation polymorphism in patients with chronic hepatitis and showed that the major strain of GBV-C/HGV had not changed for 4 years. These results suggest that amino acid substitution in the E2 region is not involved in the mechanism of persistent GBV-C/ HGV infection; these findings are consistent with the fact that GBV-C/HGV viremia ceases after the appearance of the GBV-C/HGV-E2 antibody, whereas active replication of HCV continues in the presence of the HCV-E2 antibody [23].…”

Cross‐reactivity and clinical impact of the antibody response to hepatitis C virus second envelope glycoprotein (E2)

“…One HCV 1a serum sample was nonreactive with HCV 2b E2. Thus, as suggested by previous studies with HCV 1a or 1b E2 protein [Harada et al, 1994;Lesniewski et al, 1995;Rosa et al, 1996;Yuki et al, 1996;Lee et al, 1997], the majority of HCVinfected individuals have an antibody response that reacts with E2 protein of multiple genotypes.…”

“…Some individuals have antibodies that are reactive with multiple HVR1 sequences and other individuals have a more limited response [Spengler et al, 1996;Yoshioka et al, 1997;Hattori et al, 1998;Mondelli et al, 1999]. Most individuals also possess an antibody response to conformational epitopes within HCV E2 that can be detected with E2 proteins expressed in mammalian cells [Harada et al, 1994;Lesniewski et al, 1995;Rosa et al, 1996;Yuki et al, 1996;Lee et al, 1997;Nakano et al, 1999]. This response is at least partially composed of broadly reactive antibodies because genotype 1 E2 proteins are generally reactive with HCV sera from individuals infected with various genotypes [Harada et al, 1994;Lesniewski et al, 1995;Rosa et al, 1996;Yuki et al, 1996;Lee et al, 1997].…”

“…Most individuals also possess an antibody response to conformational epitopes within HCV E2 that can be detected with E2 proteins expressed in mammalian cells [Harada et al, 1994;Lesniewski et al, 1995;Rosa et al, 1996;Yuki et al, 1996;Lee et al, 1997;Nakano et al, 1999]. This response is at least partially composed of broadly reactive antibodies because genotype 1 E2 proteins are generally reactive with HCV sera from individuals infected with various genotypes [Harada et al, 1994;Lesniewski et al, 1995;Rosa et al, 1996;Yuki et al, 1996;Lee et al, 1997]. However, it is not known whether cross-reactive antibodies are a major or minor fraction of the overall immune response to HCV E2.…”

Expression and Purification of E2/NS1 Protein of Hepatitis C Virus and Detection of Anti-E2/NS1 Antibodies in Chronic Liver Disease Patients

“…Therefore, it is predicted that anti-E2/NS1 antibodies may have some protective effect in HCV infection. Contrary to the above reports, there are studies which reveal that HCV infection persists despite the presence of a virus-specific cytotoxic T lymphocyte response and circulating antibodies to various HCV proteins [30,39]. Thus, despite the fact that E2/NS1 is an efficient immunogen, the neutralizing capacity of these antibodies remains to be documented and induction of E2-specific cellular immune responses need to be studied extensively.…”