Hepatitis C viral cDNA clones isolated from a healthy carrier donor implicated in post-transfusion non-A, non-B hepatitis.

Using a specific hepatitis C virus (HCV) antibody assay, positive blood donors responsible for the transmission of post-transfusion non-A, non-B hepatitis (PT-NANBH) were identified. cDNA fragments were isolated from one of the plasma samples of such healthy HCV carriers by using polymerase chain reactions. Nucleotide (nt) sequence analyses of the cDNA from three different regions of the viral genome revealed that they were derived from a Japanese HCV isolate that was similar but not identical to the prototype HCV previously isolated from a chronically infected chimpanzee. Homology at the nt and amino acid levels was comparatively lower in the presumed structural region than in putative nonstructural regions. This result not only confirms that HCV antibody-positive blood contains infectious HCV, but suggests the existence of different type(s) of HCV.