Immunoglobulin G and M Hepatitis C Virus Core Antibody (JCC.2) Response in Chimpanzees Infected Experimentally with Hepatitis C Virus

Abstract

Objective: To evaluate changes in serum immunoglobulin M (IgM) and G (IgG) hepatitis C virus (HCV) core antibodies after HCV infection in acute hepatitis C. Methods: Serum HCV RNA and IgM and IgG HCV core antibodies were investigated using sera sequentially sampled from three chimpanzees experimentally infected with HCV. Serum IgG HCV core antibody titer was measured using a JCC.2 enzyme-linked immunosorbent assay (ELISA) kit (Chemo-Sera-Therapeutic Research Center, Kumamoto, Japan). IgM core antibody titer was measured using horseradish peroxidase-labeled monoclonal anti-human IgM as the secondary antibody for the JCC.2 ELISA kit. Serum HCV RNA was detected using the 5′ noncoding region as the primer according to the reverse transcriptase (RT) nested polymerase chain reaction (PCR) and competitive RT-PCR method. Results: IgM JCC.2 antibody was detected when alanine aminotransferase (ALT) peaked, showing the closest correlation with the changes in ALT. A period during which IgM JCC.2 antibody was positive but HCV RNA as determined by RT-nested PCR was negative was observed after the elevation of ALT level. Conclusion: These results indicate the usefulness of detection of serum IgM JCC.2 antibody in making a definitive diagnosis of acute hepatitis C and the follow-up observation of hepatitis C.