Antibodies against synthetic oligopeptides deduced from the putative core gene for the diagnosis of hepatitis C virus infection

Abstract Immunoassays were developed to detect antibodies against oligopeptides deduced from the putative core gene of hepatitis C virus, and their performances were compared with that of the commercial immunoassay for antibodies against the product of nonstructural regions of hepatitis C virus (anti‐C100‐3). A 19‐mer oligopeptide (CP10) and a 36‐mer oligopeptide (CP9) were chemically synthesized, which represented hydrophilic regions of the product of the hepatitis C virus core gene. They were used to capture corresponding antibodies, anti‐CP10 and anti‐CP9, by enzyme‐linked immunosorbent assay in sera from patients with acute or chronic non‐A, non‐B liver disease and in blood donations. At the onset of acute non‐A, non‐B hepatitis, anti‐CP10 was detected in 15 of 20 patients (75%), and anti‐CP9 was detected in 14 patients (70%). This was more frequent than anti‐C100‐3, which was found in only 9 patients (45%). In 186 patients with chronic non‐A, non‐B liver disease, anti‐CP9, anti‐CP10 or both were detected in 170 patients (91%). This was more frequent than anti‐C100‐3, which was found in 138 patients (74%). Blood with anti‐CP10 as the single serological marker for hepatitis C virus infection transmitted non‐A, non‐B hepatitis by needlestick exposure. In sera from 558 apparently healthy blood donors, anti‐CP10 was detected in 55 donors (9.9%), anti‐CP9 was detected in 26 donors (4.7%) and anti‐C100‐3 was detected in 7 donors (1.3%). Among sera positive by at least one test, 14 were found to contain hepatitis C virus RNA; 7 of them were negative for anti‐C100‐3 but positive for anti‐CP10 and/or anti‐CP9 in high titers. These results indicate that antibodies against antigenic determinants of the hepatitis C virus core would complement anti‐C100‐3 for the diagnosis of non‐A, non‐B liver disease and contribute toward further decreasing the incidence of posttransfusion non‐A, non‐B hepatitis. (H EPATOLOGY 1992;15:180‐186).