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Ann Clin Trials Vaccines Res. 2017 | Volume 1 Issue 2
Global Vaccines & Vaccination Summit & B2B
November 01-02, 2017 | Toronto, Canada
T
ype I interferons protect cells from viral infections through
the induction of a group of genes collectively named
interferon-stimulated genes (ISGs). Among these ISGs, are the
IFITM (interferon-inducible transmembrane) which have been
shown to restrict the replication of several highly pathogenic
human viruses, including severe acute respiratory syndrome
(SARS) coronavirus, filoviruses (Marburg virus and Ebola virus),
influenza A viruses (IAVs), and flaviviruses (dengue virus). The
Genetics and Genomics group have identified these antiviral
proteins in the chicken (chIFITM) and have shown that a
reduction in chIFITM expression results in an increase in the
virus titre in CEFs infected with avian influenza A virus (AIV)
H9N2, suggesting that chIFITMs have a functional role in the
control of viral infections. The observation may have useful
implications in terms of vaccine production. To this end, a
patent was filed relating to the modification and testing of avian
IFITMs, and has now been granted in multiple countries (See
attached Appendix 1). Many vaccines have been produced in
embryonated hen’s eggs or continuous avian cell lines for more
than 30 years. (See attached Appendix 2). However, it is well
established that the rate determining step in the manufacture
of numerous vaccines is the induction of antiviral immune
responses that prevents the replication of vaccine viruses. To
generate chIFITM knock-down, we will use cutting edge genetic
approaches such the CRISPR/Cas9 system which will directly
target and knock-out chIFITM expression. We believe that
this approach will overcome the rate limiting step in vaccine
production, directly resulting in increased vaccine yields and
improve the speed at which vaccines can be manufactured.
We are currently in talks with major vaccine producers keen to
adopt this internationally patented technology, to advance the
field of both animal and human vaccine production. Discussions
with HorizonDiscovery Ltd have been very positive. Using their
extensive expertise in genetic modification using CRISPR/Cas9
technologies, we will be able to progress rapidly with this
project. Data generated from the preliminary objectives of the
project will be conveyed to GSK, Sanofi, and Ceva whom have
indicated their significant interest in this technology, however,
further proof of concept is required.
Objectives:
The broad objective of the project is to observe the
effect the knock-down of chIFITM genes expression, achieved
via siRNA and CRIPSR/Cas9 transfection methods, has on viral
titre in avian cell lines (commonly used for vaccine production)
infected with Influenza A Virus. An additional objective of
generating an IFITM-/- line of chickens will be addressed
once the outcome of these early objectives are met. These
would be exploited for both embryonated egg and CEF based
vaccines. In addition, through analysing the genetic material
of a wide variety of chicken breeds and outlying avian species
that differ in levels of resistance to these viruses, we hope
to identify versions of these proteins that give protection, in
laboratory, commercial and “backyard” chickens. Analysis
of these proteins in the chicken presents opportunities not
just for a greater understanding of viral resistance, but also
as tools to combat viruses in the poultry farming. It may be
feasible to selectively breed for birds with improved resilience
to viral infections; however, this requires the identification
of resistance-associated factors and knowledge of how they
act. The aim of our work is to understand the biology and any
genetic changes of these genes in chickens. Specifically, the
ability of IFITMs to protect the chickens against viruses will
be examined. The output of this work will be in identifying
versions of these proteins that give resistance to a number of
avian viruses. Poultry breeders and farmers will then be able
to select the protective version of the genes encoding these
proteins in future breeding programmes. Developing efficient
control strategies against these viral diseases will not only
of benefit Western societies, but also alleviate poverty in
developing countries, where these diseases are widespread,
causing devastating effects on poultry farming.
e:
mark.fife@pirbright.ac.ukIFITM knockdown/knockout technology for vaccine production
Mark Fife
and
Jon Moore
Horizon Discovery Ltd., UK