Viruses and the interferon (IFN) response : methods to improve production and to rapidly select IFN-sensitive viruses for vaccine development
Abstract
Manipulation of a virus’s capacity to circumvent the interferon (IFN) response
aids both fundamental studies as well as many practical applications including
the design of live-attenuated vaccines. However, these IFN-sensitive viruses are
often difficult to grow to high titer in cells that produce and respond to IFN. In
the first part of this study we further characterised the use of the IFN inhibitor,
Ruxolitinib (Rux) for its ability to block the IFN response and subsequently
enhance replication of IFN-sensitive viruses. This study has shown that i) Rux
could provide a more rapid and therefore more efficient alternative for the
growth of IFN-sensitive viruses than the current default option, growth in Vero
cells and ii) addition of Rux can increase growth of multiple viruses in numerous
cell-lines. These results indicate that as well as aiding fundamental studies the
addition of Rux could become a valuable technique in a number of virological
applications including live attenuated vaccine production and techniques to
isolate newly emerging viruses. In the second part of this study we developed a
novel method to isolate IFN-sensitive viruses from Paramyxoviruses, using PIV5
(Parainfluenza virus 5) as an experimental model system to obtain selection
parameters. We successfully isolated three mutant viruses (rPIV5mCh-α,
rPIV5mCh-β and PIV5 W3-γ) that each contain mutations within the IFN
antagonist V protein and the P protein which is essential for RNA replication.
Subsequently, both rPIV5mCh-α and PIV5 W3-γ were shown to contain non-
functional V proteins and exhibit IFN-sensitivity. Ultimately, this study is the first
step towards creating a general method to isolate various types of IFN-sensitive
viruses that as well as aiding fundamental studies, may be further developed as
attenuated vaccines for clinically important viruses lacking vaccines.
Type
Thesis, PhD Doctor of Philosophy
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