Technical development of a novel vaccine vehicle for cattle pathogens

Lead Research Organisation: University of Edinburgh
Department Name: Sch of Biological Sciences

Abstract

Trypanosoma theileri is a ubiquitous single celled organism present in cattle herds worldwide. Using knowledge of gene expression and protein trafficking in other trypanosomatid organisms, we have successfully developed T. theileri as a delivery system for vaccine antigens and therapeutics. Following recommendations from several Animal Health companies, we now aim to develop and demonstrate the potential of T. theileri as an effective and practical vaccine-vehicle, providing a clear route to commercialisation.

In a two-step development path, Phase 1 will focus on technical refinements and analysis of the viability of the vaccine-vehicle during storage and distribution. The flexibility of the system to express antigens from a range of pathogens will also be established. Phase 2 will entail confirmation of the in vivo efficacy of the refinements developed in Phase 1.

Combined the experiments will address key hurdles to the commercial development of this patented vaccine system.
 
Description This project stated in October 2014. The experiments engineered Trypanosoma theileri to express several heterologous antigens from episomal vectors. Many constructs to optimise the system and ensure containment were developed; in particular the maintenance of the episomal plasmids was assessed in vitro using GFP reporter expression and maintenance of antibiotic resistance, which was encoded on the transfected plasmid. This demonstrated that plasmids were maintained in the absence of selection for around 3 months- but then lost; this represented a very good kinetic of expression suitable for in vivo vaccination and immune stimulation. Also, we have explored the cold chain stability of Trypanosoma theileri and have generated robust and key data required by industry to assess the practical application of our novel delivery vehicle.

In 2016/2017 we carried out in vivo trials using episomal expression vectors, as well as integrative expression vectors in an auxotrophic mutant. The immunogenicity of the new vehicles has been analysed and compared with earlier studies. To date our evidence is that the alternative delivery routes using episomal vectors can stimulate immunity but this is not as good as had been previously seen with a construct integrated into the genome of the parasite. It is not clear why the immune stimulation was less effective but it might be related to the expression levels of the antigen. This can be improved in future by codon optimisation.

The genome of the T. theileri vehicle has also been completed and analysed in comparison to pathogenic trypanosomes and this has revealed some of the unique biology of both parasites; for T. theileri this highlighted the adaptations for immune evasion and how these differ from T. brucei.

Finally, as an extension to the funded work we developed methods to differentiate the parasite to its insect form because this is expected to show enhanced thermal stability compared with the bloodstream form parasites. We also adapted to culture and successfully transfected a related Trypanosomatidae of sheep, Trypanosoma melophagium, which might form the basis of a vaccine delivery vehicle for ovine pathgens- similar to the approach using T. theileri for cattle pathogens.
Exploitation Route Our research programme aimed to evaluate and develop a novel system for the sustained delivery of an unlimited range of pathogen antigens specific to cattle. Being defined and characterised in terms of their immunogenicity, vaccinated and diseased animals are able to be identified and distinguished. Moreover, the technology proposed has economic advantages over the existing expensive and labour-intensive production of attenuated vaccines. This offers clear advantages to the agricultural and animal healthcare industry at large.

The proposal developed early-stage work, with substantial commitment from an Industrial Partner, to demonstrate utility and provide the required scientific validation to stimulate further development in an industrial setting with the partner company.

The proposal fulfilled the strategic remit of the animal sciences panel with respect to:

The 'control of infectious diseases', (priority area) comprising 'identification of protective antigens', 'vaccinology' and 'improved antigen delivery systems'. Strategic plan objectives for 'Sustainable Agriculture' comprise 'host/pathogen interactions', 'animal welfare' and the 'control of animal diseases'.

In 2016/2017 we successfully secured further funding based on the concepts developed in this proposal. One grant was for development of an equivalent vaccination system using sheep trypanosomatids (Royal Society Challenge award), based on preliminary work carried out in this proposal. Another was to explore the viability of the current system to vaccinate against major zoonotic infections that pose risk for human epidemics (Innovate UK). Finally, application of the approach to combat East Coast Fever has been pursued through the award of funding through the Bill and Melinda Gates foundation to assess the delivery vehicle for effective immunisation against that pathogen. This new funding is currently underway. There is potential for further ongoing funding from the Bill and Melinda Gates foundation to support this ongoing work.

We have also secured commercial interest on the Trypanosoma melophagium platform for vaccination against sheep pathogens. We are currently negotiating contributory support from Roslin Technologies Etc and the BBBSRC impact accelerator funds to pursue proof of concept work around this activity.
Sectors Agriculture, Food and Drink,Education,Manufacturing, including Industrial Biotechology

 
Description The work has been progressed to European patent filing, and this was granted in early 2017. A US patent was also awarded in 2018
First Year Of Impact 2017
Sector Agriculture, Food and Drink
Impact Types Economic

 
Description GCRF Challenge award
Amount £117,261 (GBP)
Funding ID CH160034 
Organisation The Royal Society 
Sector Charity/Non Profit
Country United Kingdom
Start 12/2016 
End 10/2018
 
Description SBRI Vaccines for Global Epidemics - Preclinical Stage 1
Amount £334,000 (GBP)
Funding ID 86235-544135 
Organisation Innovate UK 
Sector Public
Country United Kingdom
Start 04/2017 
End 04/2018
 
Description Supporting Evidence Based Interventions-Evaluation of a trypanosomatid vaccine vehicle to combat livestock infections in LMIC
Amount £191,361 (GBP)
Organisation Bill and Melinda Gates Foundation 
Sector Charity/Non Profit
Country United States
Start 04/2019 
End 09/2020
 
Title Growth and transfection of Trypanosoma melophagium 
Description As a complement to our work with the cattle trypanosomatid Trypanosoma theileri, we also isolated and adapted to culture a line of the sheep trypanosomatid, Trypanosoma melophagium. These were solvated from feral Soay sheep on St Kilda and adapted to in vitro culture. methods for their genetic transformation were then derived. 
Type Of Material Cell line 
Year Produced 2017 
Provided To Others? No  
Impact Trypanosoma melophagium is being developed as a vaccination platform for sheep. This is under development. 
 
Title Trypanosoma theileri genome sequence 
Description Genome sequence 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
Impact Permits comparative genomic analysis with other kinetoplastid parasites 
URL https://www.ncbi.nlm.nih.gov/bioproject/PRJNA273795
 
Description Collaboration with Moredun 
Organisation Moredun Research Institute
Country United Kingdom 
Sector Charity/Non Profit 
PI Contribution Provision of transgenic T theileri for the infection of cattle in a contained facility to evaluate immune responses generated toe expressed antigens
Collaborator Contribution Provision of a contained cattle facility
Impact See publication linked to this output
Start Year 2009
 
Description Collaboration with researchers at Roslin Institute 
Organisation University of Edinburgh
Department The Roslin Institute
Country United Kingdom 
Sector Academic/University 
PI Contribution We expressed antigens of the cattle Parasite Trypanosoma congolense in Trypanosoma theileri and this was used as the basis of experiments to evaluate the ability of these T congolense antigens to generate immune responses in cattle.
Collaborator Contribution Antigen sequences were provided to generate the recombinant T. theileri cell lines and these are being evaluated by them for immunogenicity in cattle
Impact A funding application has been submitted to the Bill and Melinda Gates foundation to progress development of this vaccination approach
Start Year 2016
 
Description Intervet collaboration 
Organisation Intervet-Schering Plough
Country United States 
Sector Private 
PI Contribution We evaluated a novel vaccine vehicle for the delivery of antigens to cattle. We expressed an antigen provided by Intervet (after expression optimisation of the vaccine delivery vehicle) and tested its immunogenicity in cattle.
Collaborator Contribution Intervet provided technical guidance, reagents and IP protection support. They also provided a cash contribution to the award as required by the Industrial Partnership scheme.
Impact Publication Mott, G. A.; Wilson, R.; Fernando, A.; Robinson, A.; MacGregor, P.; Kennedy, D.; Schaap, D.; Matthews, J. B. and Matthews, K. R. (2011) Targetting cattle-borne zoonoses and cattle pathogens using a novel trypanosomatid-based delivery system. PLoS Pathogens, 7(10):e1002340. Outreach Wellcome Trust blog: http://blog.wellcome.ac.uk/2012/02/14/neglected-tropical-diseases-working-with-animals/ BBSRC news feature: http://www.bbsrc.ac.uk/news/food-security/2011/111028-pr-cattle-parasite-vaccine.aspx Veterinary record news report: http://veterinaryrecord.bmj.com/content/169/21/541.1.extract
Start Year 2009
 
Description collaboration with the 'Supporting Evidence based Interventions' programme at the University of Edinburgh 
Organisation University of Edinburgh
Country United Kingdom 
Sector Academic/University 
PI Contribution Our vaccine vehicle technology is being use din a collaboration with the Supporting Evidence Based interventions programme at the University of Edinburgh to investigate the potential of using the cattle vaccination approach to target thjileria parasites in Africa
Collaborator Contribution The SEBI programme seeks to develop novel technologies to address issues of livestock productivity in sub Saharan Africa. It is funded by the Bill and Melinda Gates foundation.
Impact The work is ongoing
Start Year 2018
 
Title 'Recombinant Trypanosoma theileri parasite' 
Description We developed Trypanosome theileri as a vaccine vehicle for the delivery of antigens and other therapeutics to cattle 
IP Reference WO2012013939 
Protection Patent application published
Year Protection Granted
Licensed No
Impact The patent application is under review in the US at present. Development work is being supported by a BBBSRC Super Follow on fund application
 
Title RECOMBINANT TRYPANOSOMA THEILERI PARASITE 
Description Patent for the production of recombinant Trypanosoma theileri for the purposes of vaccine delivery 
IP Reference EP2598163 
Protection Patent granted
Year Protection Granted 2017
Licensed No
Impact None
 
Description vaccination for trypanosomatid parasites discussion group 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Work shop on vaccination for trypanosomatid parasites; held at the Veterinary School, University of Edinburgh
Year(s) Of Engagement Activity 2019