Antibody to hepatitis C virus second envelope (HCV‐E2) glycoprotein: A new marker of HCV infection closely associated with viremia

Abstract

The second envelope protein (E2) of the hepatitis C virus (HCV) was cloned and expressed in Chinese hamster ovary (CHO) cells. This E2 glycoprotein was purified using ion exchange and lectin chromatography and used to construct an enzyme immunoassay for HCV E2 antibodies. The assay was shown to have good specificity, and detection of E2 antibodies was positively correlated (97.3%) to the presence of HCV RNA in serum and plasma. A high concordance between HCV 2.0 and E2 EIA reactivities was also observed. E2 antibody was the first serological marker to appear in 3/5 HCV seroconversion panels. This work demonstrated that 42.4% of core and 15.4% of NS3 indeterminate specimens also contained antibodies to E2, suggesting that HCV infection had occurred in these individuals. The E2 antibody assay was used to evaluate HCV 2.0 EIA-positive, HCV 3.0 EIA-negative plasma donors with indeterminate reactivity on RIBA HCV 2.0 or MATRIX HCV 1.0. Several HCV 3.0-negative specimens were shown to contain E2 antibodies in addition to an original indeterminate serological marker, primarily core. It is concluded that anti-E2 is a useful marker for determining HCV infection, and that the presence of antibodies to two nonoverlapping viral gene products suggests true HCV exposure. New HCV 3.0 blood screening tests should detect HCV 2.0-positive donors who present with an indeterminate pattern by RIBA or MATRIX and who also carry E2 antibodies.

Characterization of truncated forms of hepatitis C virus glycoproteins.

“…Previous results have shown that truncated forms of E2 ending at amino acids 661,664,668,683,699,710 and 715 are secreted (Lesniewski et al, 1995 ;Matsuura et al, 1994 ;Nishihara et al, 1993 ;Selby et al, 1994). The size of the deletion did not affect the level of secretion, since truncated E2 glycoproteins ending at amino acids 661, 699, 710 and 715 were equally secreted (Selby et al, 1994), and we obtained similar results for truncated E2 glycoproteins expressed by vaccinia virus.…”

“…Properly folded forms can be used in biochemical studies, such as defining the nature of E2 intramolecular disulfide bonds. Secreted HCV glycoproteins can also be used to study their interaction with the cell surface (Rosa et al, 1996), or for diagnostic purposes (Lesniewski et al, 1995). In this work, Sindbis and vaccinia virus recombinants were used to express full-length and carboxyterminally truncated forms of HCV glycoproteins.…”

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

“…In this study, there were low viremic cases that could not be structural (core) and nonstructural HCV proteins. [13][14][15] However, our data indicate that while highly viremic genotyped. An explanation for such cases is infection with a unique viral genotype.…”

“…This is compatible with a few recent studies (62%), compared with 2 of the 70 patients with high using native E2/NS1 glycoprotein. [13][14][15] viremia of ¢10 6 copies/mL (3%). Serum HCV-RNA levIn previous studies, the E2/NS1 antibody response els expressed as log 10 (copy numbers of HCV RNA per was not quantitatively evaluated in relation to HCV mL serum) were significantly higher in E2/NS1 anti-replicative levels.…”

“…[10][11][12][13][14][15] The prevalence, however, differs considerably had it (97%) (P õ .01). As for the relation to HCV geno-among studies.…”