Analysis of the core and E1 envelope region sequences of a novel variant of hepatitis C virus obtained in Indonesia.

Hepatitis C virus (HCV) is currently classified into 6 major types, HCV-1 through -6, each of which can be further divided into a few subtypes, e.g., HCV-1a, -1b, -1c, etc., on the basis of sequence variation of the viral genome. The core and E1 envelope regions of HCV genome were amplified from sera of Indonesian patients using reverse transcription-polymerase chain reaction. Sequence analysis of both core and E1 regions followed by molecular evolutionary phylogenetic analysis identified a novel sequence variant of HCV-1 (Td-6). Antibodies in the serum from which Td-6 was isolated reacted only marginally to the core protein of HCV-J, a representative strain of HCV-1b, despite strong antibody response against a mixture of the core, NS3 and NS4 proteins of HCV-1a. The possible mechanism for the diminished reactivity of the antibodies in the serum to the core protein of HCV-J is discussed.