The application and the proposed dealings The OGTR has received an application from Imugene Limited (Imugene) for a licence for the intentional release of genetically modified (GM) fowl adenoviruses (FAV) into the environment. The adenovirus vector used in the genetic modification was developed by the CSIRO. Imugene has agreements with the CSIRO for collaboration and further development of this work. The release is proposed to occur on a limited scale and under controlled conditions within Physical Containment Level 1 (PC1) animal containment facilities that simulate commercial farming practices. The proposed trial involves six GMOs that have each been modified by introducing a chicken gene, ChIFN-g, under the control of one of two promoters. Each GMO has had one of three different sized deletions made in the right hand end of the viral sequence. ChIFN-g encodes the protein interferon gamma that plays a role in regulating the immune system of chickens. Inoculation with the GM viruses is expected to stimulate the immune response of chickens and make them less susceptible to infections. Chickens raised in commercial production facilities are exposed to a range of organisms that may cause low grade infections that adversely affect their general health and production. To counteract this, antibiotics may be added to the chicken feed. If the research is successful, the inoculation of chickens with the modified virus may provide an alternative to the use of antibiotics in commercial chicken production. Imugene proposes to carry out the trials at up to three locations in Victoria. The proposed PC1 animal containment measures include the use of secure facilities to prevent the escape of the chickens and/or access by other animals. Dissemination of the GM virus would be limited due to its inability to infect organisms other than birds; by its limited ability to survive in the environment outside its natural host; and the trial sites’ remoteness from other chicken production facilities. During the trial period, from the time of issuing of the licence until December 2006, up to 5000 chickens will be inoculated with the GM viruses. Chickens will be inoculated either in ovo or within the first 2 weeks after hatching (via drinking water, intra-ocular delivery or spray). None of the chickens from the release, or their by-products, would be used for animal feed or human food. Following each trial, inoculated chickens will be euthanased and all animal material disposed of under strict conditions that would destroy the GMOs. The aim of the proposed trial is to evaluate the performance of the GM viruses in chickens, using a range of indicators such as chicken health, weight gain and feed conversion rate. The trials will also allow additional research on the potential of the viruses to spread from one chicken to another within the secure facilities. The Australian Pesticides and Veterinary Medicines Authority (APVMA) has regulatory responsibility for veterinary medicine use in Australia, including the registration of vaccines, under the Agricultural and Veterinary Chemicals Code Act (1994). Data from this proposed trial on the effectiveness of the treatment is necessary before the APVMA could evaluate an application for registration of the GM viruses as products for veterinary use. Further information about the APVMA can be obtained from www.apvma.gov.au.
Previous releases of the GMO Experiments with these GMOs have previously been conducted by the CSIRO in PC2 level (laboratory and animal) containment facilities under licence DNIR 068/2002 and under the former voluntary system overseen by the Genetic Manipulation Advisory Committee (GMAC) under proposal numbers 2332 and 3302. However, this is the first time that work with the GMOs would be conducted at the PC1 level of containment. Parent organism Viruses are microscopic infectious particles, composed of a protein coat and a nucleic acid core, that cause a variety of diseases among all groups of living organisms. However, viruses cannot replicate on their own, they require the assistance of the cell(s) which they infect to do so. Unlike some other viruses, when adenoviruses infect cells their genetic material does not integrate with that of the host cell, making any potential gene transfer to the host cell highly improbable. There are over 40 different types of adenoviruses. These are very species specific and, usually, mild pathogens. For example, human adenoviruses cause respiratory tract infections, such as the “common cold” and eye infections. Twelve types of fowl adenoviruses (from the virus family Adenoviridae, genus Aviadenovirus) have been found in worldwide in several avian species, including chickens, quails, turkeys, ducks, guinea fowls, pigeons and budgerigars. Fowl adenoviruses are endemic in the Australian poultry flocks and probably in other bird populations. The parent organism of the GM viruses proposed for release, fowl adenovirus serotype 8 (FAV-8) strain CFA40, is currently used as a live vaccine in commercial breeder chickens in all States and Territories in Australia. It was originally isolated from an outbreak of inclusion body hepatitis in chickens in Victoria in 1985 by the Victorian Research Institute. FAVs, including FAV-8, do not cause disease in people, plants or animals other than birds. FAV-8 has only been found to replicate in avian cells and is unable to infect organisms other than birds. Genetic modification and its effect A total of six GM viruses are proposed for release. Each GM virus has been modified by the addition of the ChIFN-g gene that encodes the chicken immuno-regulatory protein interferon gamma. This molecule is active in chicken cells but not in bovine cells and is not expected to be active in other mammalian cells. The two different promoter sequences used to control expression of the introduced gene are either the major late promoter (MLP) derived from FAV-8 itself, or the immediate early promoter from human cytomegalovirus (hCMV). One of three deletions were also made in the right hand end of the viral sequence. A polyadenylation signal, derived from the polyoma virus, is present in each construct to facilitate protein translation. The various combinations are detailed in the table below.
GMOs proposed for release GMO Parent virus Gene inserted Promoter Deletion 1 FAV-8 ChIFN-g gene FAV major late promoter (FAV MLP) 50 base pair (bp) deletion 2 FAV-8 ChIFN-g gene Human Cytomegalovirus immediate early promoter (hCMV IEP) 50 bp deletion 3 FAV-8 ChIFN-g gene FAV MLP 1.3 kilobase pair (kbp) deletion 4 FAV-8 ChIFN-g gene hMCV IEP 1.3 kbp deletion 5 FAV-8 ChIFN-g gene FAV MLP 2.2 kbp deletion 6 FAV-8 ChIFN-g gene hMCV IEP 2.2 kbp deletion Method of gene transfer The genes were inserted into fowl adenovirus by homologous recombination in chicken cell tissue culture, by use of the plasmid vector pGEM-11Zf(+). Infectious GM virus was then recovered and purified. None of the plasmid sequences are present in the final GM adenovirus.
Consultation on draft Risk Assessment and Risk Management Plan The Regulator has made an initial assessment as to whether the proposed release may pose significant risks to human health and safety or the environment, in accordance with section 49 of the Act. Due to the low risk potential of the GMO, the control measures that are proposed, and the limited scale and scope of the dealings, the Regulator has decided that the proposed release does not pose a significant risk to human health and safety or the environment.
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