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

1.2 An elusive pathogen.
9
The emergence of a new human pathogen presents the greatest of
challenges to modern virology and the discovery of human immunodeficiency
virus (HIV) in the early 1980s set a precedent for the field. The discipline of
virology was not quite 100 years old when HIV was first isolated (15).
However, proficient replication of HIV in vitro allowed the scientific community
to characterise the virus exceptionally quickly. From the identification of HIV,
to approval of the first specific therapy (AZT) by the Food and Drug
Administration took less than 5 years (213, 226) (and FDA website).
Developments came so quickly that CD4 was identified as the major entry
receptor before the politics of naming the new pathogen had been resolved
(178, 199, 272).
As illustrated by HIV, rapid progress in the study of a virus requires an
appropriate model system capable of supporting virus replication; from its
inception virology has been dominated by species for which such platforms
exist. Early research focused on viruses that infect hosts such as bacteria,
plants and birds. During the mid 20 th century, the advent of mammalian cell
culture allowed fast and consistent in vitro studies of viral replication.
However, not all viruses replicate in vitro, which presents a problem when
studying pathogens with host ranges limited to humans and higher primates
(78).
In vivo, it is thought that HCV replicates in hepatocytes within the liver.
However, the hepatocyte is a highly specialised cell type and the liver a