N. Yuki et al., QUANTITATIVE-ANALYSIS OF ANTIBODY TO HEPATITIS-C VIRUS ENVELOPE-2 GLYCOPROTEIN IN PATIENTS WITH CHRONIC HEPATITIS-C VIRUS-INFECTION, Hepatology, 23(5), 1996, pp. 947-952
The significance of circulating antibody to hepatitis C virus (HCV) en
velope glycoprotein 2 (E2)/nonstructural protein 1 (NS1) glycoprotein
was studied in 83 patients with chronic HCV infection diagnosed by pol
ymerase chain reaction (PCR). E2/NS1 antibody was quantitatively exami
ned by a passive hemagglutination test using recombinant E2/NS1 glycop
rotein encompassing amino acids 388 to 664 of the HCV-H strain. The re
sults were correlated with clinical and virological features such as g
enotypes and viremic levels assessed by a competitive reverse-transcri
ption PCR assay. E2/NS1 antibody was found in 73 patients (88%), and i
ts occurrence was related to viremic levels. ES/NS1 antibody titers we
re low in asymptomatic HCV carriers with low levels of viral replicati
on; 9 of 17 such patients tested positive for E2/NS1 antibody (53%), c
ompared with 64 of 66 chronic hepatitis C patients (97%) (P <.01). A s
ignificant direct relationship was observed between viremic levels and
EP/NS1 antibody titers (r = .52, P <.01), Of the 13 patients with low
viremic levels of <10(6) copies/mL, only 5 tested positive for E2/NS1
antibody (38%), whereas 68 of the 70 patients with viremic levels of
greater than or equal to 10(6) copies/mL had it (97%) (P <.01). As for
the relation to HCV genotypes, no difference was seen in E2/NS1 antib
ody titers among genotypes examined (Ib, 2a, and 2b). These findings s
uggest that the E2/NS1 antibody tested exhibits no neutralizing activi
ty in chronic HCV infection but may serve as a serological indicator o
f active virus replication.