Isolation of a cDNA cLone Derived from a Blood-Borne Non-A, Non-B Viral Hepatitis Genome

TLDR

The study demonstrates that a molecular approach can aid isolation and characterization of unidentified infectious agents. The authors constructed a random‑primed cDNA library from plasma containing the uncharacterized non‑A, non‑B hepatitis agent and screened it with patient serum. They isolated a cDNA clone encoding a NANBH‑specific antigen, derived from a >10,000‑nt positive‑stranded RNA genome, suggesting the agent resembles togaviridae or flaviviridae.

Abstract

A random-primed complementary DNA library was constructed from plasma containing the uncharacterized non-A, non-B hepatitis (NANBH) agent and screened with serum from a patient diagnosed with NANBH. A complementary DNA clone was isolated that was shown to encode an antigen associated specifically with NANBH infections. This clone is not derived from host DNA but from an RNA molecule present in NANBH infections that consists of at least 10,000 nucleotides and that is positive-stranded with respect to the encoded NANBH antigen. These data indicate that this clone is derived from the genome of the NANBH agent and are consistent with the agent being similar to the togaviridae or flaviviridae. This molecular approach should be of great value in the isolation and characterization of other unidentified infectious agents.