Typing of Hepatitis C Virus Antibody with Specific Peptides in Seropositive Blood Donors and Comparison with Genotyping of Viral RNA

Abstract

Background and objectives: Serotyping of antibody to hepatitis C virus (anti- HCV) with specific peptides has been developed as an alternate method for typing HCV infections. The method does not require a prior amplification of viral RNA sequences from the sample. Identification of the viral genotype may be relevant for prognosis and clinical management. Materials and methods: We used a previously described HCV serotyping assay (RIBA™ HCV Serotype SIA kit, Chiron Corp.) to investigate the serotype in 191 samples from blood donors selected for anti-HCV patterns (positive and indeterminate), ALT levels, and the presence or absence of viral RNA. The serotypes were compared with the genotypes obtained from typing the 5'-noncoding region of the viral RNA in 82 virémie samples. Results: We were able to obtain the viral serotype in 85% (114/134) of samples positive for anti-HCV but in only 3.5% (2/57) of the indeterminates. Lack of anti-NS4 in the sample was significantly associated with both untypable results and the presence of HCV serotypes other than serotype 1. The overall correlation with genotyping was 78% (64/82), rising to 95.5% (64/67) if only samples that could be both genotyped and serotyped were considered. The assay was easy to perform, gave reactivity patterns easy to interpret, and performed with high proficiency on anti-HCV-positive samples lacking detectable levels of viral RNA. Conclusions: This is a practical and useful method for typing HCV infections in the clinical setting. The poor ability of the Core peptides to give the serotype in samples lacking anti-NS4 and the lack of specific peptides to recognize HCV types other than 1, 2, and 3 are, however, some aspects of the method that need improvement in the future.

Expression of Hepatitis C Virus E2 Ectodomain in <italic>E. coli</italic> and Its Application in the Detection of Anti-E2 Antibodies in Human Sera

“…Some reports have suggested that including anti-E2 antibody testing into current EIA kits could improve their performance [14][15][16][17]. Our results shown here and elsewhere [19,20] demonstrated that E. coli-derived E2 fragments reacted specifically with infected patient sera in Western blot and elicited antibodies in rabbits against glycosylated E2 expressed in mammalian cells, indicating E2 proteins expressed in bacteria shared antigenic/immunogenic epitopes with mammalian E2 glycoproteins.…”

“…Therefore, E2 has become a major target in anti-HCV vaccine research. Humoral immune responses against E2 also have diagnostic significance, since there have been studies showing that testing for antibodies against E2 could improve the performance of current HCV EIA kits, which do not incorporate any forms of envelope proteins [14][15][16][17].…”