The role of scavenger receptor BI in hepatitis - eTheses Repository ...

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PCR). This technique is highly sensitive making it difficult to discriminate
between passive cellular uptake of HCV particles and ‘true’ virus entry
followed by genome replication. Studies were able to eliminate false positives
by carrying out RT-PCR for both plus strand HCV genomes and negative
strand replicative intermediates (59, 133, 304). Although these reports
demonstrated in vitro HCV replication the techniques did not allow detailed
characterisation of the virus (18).
Investigating the expression and function of viral proteins in isolation was a
more straightforward task. The existence of gene delivery systems such as
recombinant plasmids, vaccinia virus and adeno virus, allowed the expression
of HCV gene(s) in bacterial and mammalian cells (17, 248, 340).
Observation(s) of the proteins’ enzymatic and regulatory functions contributed
to a basic understanding of the viral component parts. Indeed, such
techniques remain a vital tool in the ongoing investigation of HCV. However,
the absence of in vitro model supporting replication prevented mechanistic
studies to address how these viral proteins acted in concert. As a result
elucidating processes such as genome replication or particle assembly
remained out of reach.
Another limitation of early HCV research was the lack of an infectious clone.
Studies using chimpanzees or primary human hepatocytes relied on HCV
positive patient sera as a source of infectivity, however as patient derived
particles are genetically diverse there was little understanding of what
constituted an infectious HCV particle. In 1997, Kolykhalov et. al. derived a