Tetsuo Kawahara

Clinical evaluation of three anti-HCV ELISAs in patients with various liver diseases.

We measured antibodies to hepatitis C virus (HCV) in 380 patients with various liver diseases by three enzyme-linked immunosorbent assays (ELISAs): HCV antibody ELISA test (C100), KCL-163 (KCL) corresponding to the nonstructural protein of HCV, and JCC based on the translation product of the presumptive HCV core gene. Of 233 cases of non-A, non-B (NANB) liver disease, 63.9% were anti-C100 positive, 69.1% were anti-KCL positive, and 79.8% were anti-JCC positive. Detection of serum HCV-RNA in 213 cases of chronic NANB liver disease revealed that the concordance was 80.3% for C100, 86.4% for KCL, 94.8% for JCC, and 95.3% for all three ELISAs. Overall, 85.4% of chronic NANB cases were considered to have type C disease with HCV infection. The most reliable assays for diagnosing chronic NANB liver disease as type C appeared to be the KCL and JCC ELISAs.

Evaluation of three hepatitis C virus-related antibodies C100, KCL-163, JCC. Tests for screening blood donors.

To evaluate the most effective method for detecting hepatitis C virus (HCV) carriers in a large population of blood donors, HCV-related antibodies were measured in 919 donor serum samples using three different enzyme-linked immunosorbent assays. The antibodies were C100 and KCL-163, nonstructural proteins of HCV, as well as JCC, a translation product of the presumptive HCV core gene. Fourteen (1.5%), 12 (1.3%), and 13 (1.4%) specimens were positive for anti-C100, anti-KCL-163, and anti-JCC, respectively. HCV RNA was detected by the polymerase chain reaction in seven (25.0%) of the 28 specimens that were anti-HCV-positive by at least one of the three assays. Four of the seven specimens were detected by anti-C100 screening, while the remaining three were not. All seven specimens were positive for KCL-163 and/or JCC antibodies. These findings suggest that screening for both KCL-163 and JCC antibodies may be of particular use in accurately identifying HCV-positive blood.

Detection of antibodies to hepatitis C virus (anti-HCV) in patients with various liver diseases, by an ELISA (KCL-163) test consisting of synthetic peptides corresponding to an HCV genome

SummaryIn 1989, the Chiron group developed an enzyme immunoassay system (C100) for detecting antibodies to hepatitis C virus (anti-HCV). In our examinations, the postivie rate was 65.3% of the total number of patients (199) with non-A, non-B (NANB) liver disease. Additionally, a specific ELISA system (KCL-163) was developed by Kaketsuken (Kumamoto, Japan) based on synthetic peptides corresponding to an HCV genome of a Japanese isolate. In this study, we measured antibodies to HCV by KCL-163, and compaired the results of KCL-163 with that of C100 in patients with various liver diseases. Our emphasis was on the discrepancies between the results of the two types of ELISA. We concluded that it was not sufficient to diagnose hepatitis C only by assay systems based on the C100-3 region of an HCV genome, and that KCL-163 was superior to C100 in its specificity and sensitivity in the diagnosis of hepatitis C.

Detection of antibody against nonstructural (NS) 5 region of hepatitis C virus polyprotein

Abstract A cDNA clone, C8-2, derived from nonstructural (NS) protein 5 region of hepatitis C virus (HCV) genome hasbeen isolated and was expressed in Escherichia coli as a fusion protein with β -galactosidase ( β -Gal). The recombinant protein, β -Gal/C8-2, was partially purified and used for detection of anti-HCV antibody by enzyme-linked immunosorbent assay (ELISA). Anti-C8-2 antibody was detected in 47% of patients with post-transfusion non-A, non-B (NANB) acute hepatitis and in 55% of patients with NANB chronic liver diseases. Of 1491 normal blood donors, ten (0.7%) were positive for anti-C8-2 antibody, and three of these ten samples were negative for anti-C100-3 antibody. HCV RNA was detected in one of these three samples. These results suggest that the recombinant protein containing C8-2 peptide may be useful as another nonstructural protein epitope for diagnosis of hepatitis C and screening of blood donors.