RESUMO
Synthetic peptides representing sequences encoded at the 5'-terminus of E2/NS1 in hepatitis C virus (HCV) were constructed. Peptides synthesized based on the sequences of four distinct HCV isolates were used to develop enzyme immunoassays (EIAs) for detection of antibodies in chronic HCV patients and in HCV-infected plasma donors. HCV sequence-specific antibodies were detected among patients with chronic HCV from the United States and Italy at frequencies of 22.2% and 55.8%, respectively. Similarly, sequence-specific antibodies were detected in 54.6% of U.S. and 55.6% of Japanese commercial plasma donors who had previous evidence of HCV exposure. Our data support earlier findings of geographic variability among HCV variants. The region encoded by amino acids (aa) 380-436 was shown to contain at least one variant-specific and one conserved epitope. The data further indicate that a majority of patients chronically infected with HCV (58.1% U.S., 68.8% Italy) have antibodies directed to the 5'-terminus of the E2/NS1 gene product. We conclude that genotypic variability within the E2/NS1 gene of HCV results in antigenically distinct variants.
Assuntos
Variação Antigênica/genética , Antígenos Virais/genética , Hepacivirus/genética , Hepacivirus/imunologia , Anticorpos Anti-Hepatite/sangue , Proteínas do Envelope Viral/genética , Sequência de Aminoácidos , Epitopos/genética , Anticorpos Anti-Hepatite/imunologia , Hepatite C/tratamento farmacológico , Hepatite C/imunologia , Anticorpos Anti-Hepatite C , Humanos , Interferons/uso terapêutico , Dados de Sequência Molecular , Fragmentos de Peptídeos/síntese química , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/imunologia , Proteínas do Envelope Viral/imunologiaRESUMO
An enzyme immunoassay (EIA) which utilizes a solid phase coated with a recombinant antigen (c100-3) derived from the hepatitis C virus (HCV) genome was evaluated for efficacy in the detection of antibodies to HCV (anti-HCV). The sensitivity of the antibody test was demonstrated by the detection of anti-HCV in a well-characterized panel of human specimens known to contain the infectious agent of non-A, non-B hepatitis. The specificity of the anti-HCV test was evaluated by testing 6,118 serum specimens from volunteer blood donors considered to be at low risk for exposure to HCV. The specificity of the anti-HCV EIA was demonstrated to be 99.56%, since 6,069 of 6,096 specimens from this low-risk group were nonreactive. A total of 49 (0.80%) of the 6,118 specimens were repeatedly reactive in the test, and 22 (46.81%) of the 47 specimens available for additional testing were confirmed as positive for antibodies to HCV c100-3. Among commercial plasma donors, 390 (10.49%) of 3,718 specimens were repeatedly reactive in the EIA. A total of 375 (97.40%) of the 385 specimens available for further testing were confirmed as positive. These limited data indicate that the prevalence of antibodies to HCV is 0.36% (22 confirmed positives among 6,118 specimens) among volunteer blood donors and 10.08% (375 confirmed positives among 3,718 specimens) among commercial plasma donors. The importance of confirmatory testing is discussed.