Full-length infectious HCV chimeras.

: One hallmark of HCV is its pronounced genetic plasticity, caused by error-prone RNA replication, which probably contributes to its remarkable ability to establish chronic infections. On the basis of phylogenetic analyses, HCV variants are classified into six genotypes (GTs), each comprising a variable number of subtypes. Presumably, these genetic differences, which range from 33 to 35% at the nucleotide level among genotypes and from 22 to 25% between subtypes, are reflected by divergent biological properties of the respective isolates. The unprecedented replication efficiency of the JFH1 isolate (a GT2a strain derived from a Japanese patient with fulminant hepatitis) in transfected Huh-7 cells represents a characteristic feature intrinsic to this particular isolate and has very recently made possible the investigation of the complete viral replication cycle in cultured cells. To expand the scope of this novel HCV infection system, several groups have constructed chimeric HCV genomes comprising JFH1-derived replicase proteins and structural proteins from heterologous HCV strains. This chapter describes experimental procedures for evaluation of the properties of infectious full-length HCV chimeras.