A second group of hepatitis C viruses.

Area of Science:

• Virology
• Molecular Biology
• Hepatology

Background:

• Non-A non-B hepatitis (NANBH) posed a significant diagnostic challenge.
• Hepatitis C virus (HCV) was identified as a causative agent.
• Understanding HCV genetic diversity is crucial for diagnosis and treatment.

Purpose of the Study:

• To investigate the genetic diversity of Hepatitis C virus (HCV).
• To identify distinct groups within the HCV genome.
• To assess the diagnostic potential of different HCV genetic variants.

Main Methods:

• Immunoscreening of a cDNA library from NANBH patients using expression vector lambda gt11.
• Isolation and nucleotide sequencing of six additional HCV-related cDNA clones.
• Analysis of nucleotide and amino acid sequence divergence between identified HCV groups.
• Expression of polypeptides from cDNA clones in Escherichia coli for antibody reactivity testing.

Main Results:

• Identification of at least two distinct groups of Hepatitis C virus (HCV): Group I and Group II.
• Significant divergence in nucleotide and amino acid sequences between Group I and Group II HCV.
• Genetic variation between groups shows resemblance to differences in the NS3 region of Japanese encephalitis virus and West Nile fever virus.
• Polypeptides from both Group I (clone 11-7) and Group II (clone E) reacted with antibodies from chronic NANBH patients, indicating distinct antigenic properties.

Conclusions:

• The study provides strong evidence for the existence of at least two genetically distinct groups of Hepatitis C virus (HCV).
• The observed genetic variation suggests significant diversity within the HCV genome.
• The findings indicate the necessity of considering different HCV groups for accurate diagnosis and potentially for therapeutic strategies.