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

1.7 HCV and lipoproteins.
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Over the last 15 years there has been a steady accumulation of evidence to
implicate lipoproteins in HCV infection. Initial observations came from infected
patient sera in the early 1990s, however only with the advent of the HCVcc
system has the true nature of HCV-lipoprotein association become apparent.
The following section covers the extraordinary ability of HCV to exploit the
liver’s central role in lipid metabolism.
Differential centrifugation through a continuous gradient of inert medium, such
as sucrose, allows the separation of viruses according to their density, which
is in turn determined by the relative nucleic acid, protein and lipid composition
of individual virions (102). This technique has been used by virologists for
over 40 years (230), consequently analysis of HCV by density centrifugation
was almost inevitable. As a rule particle density is relatively invariable within
viral species, for instance Adenovirus particles have a homogenous density of
~1.34g/ml (55, 102). Therefore it came as some surprise to find that upon
fractionation of HCV derived from patient sera, RNA genomes could be found
across a broad range of densities; 1.03-1.20 g/ml (214). A large proportion of
virions appeared to be of particular low density (~1.08g/ml) suggesting a high
lipid content, indeed removal of lipids with detergents increased virion density
to 1.25g/ml (214). The density heterogeneity and apparent high lipid
composition of serum HCV particles does not conform to the traditional model
of an enveloped virion, therefore it was hypothesised that HCV associates
with host serum components.