Accelerated development of a safe and easily manufactured Q fever vaccine

Lead Research Organisation: Moredun Research Institute
Department Name: Disease Control

Abstract

Q fever is an important and highly contagious disease of worldwide importance affecting both livestock and humans caused by the intracellular Gram-negative bacterium, Coxiella burnetii. Infection of humans occurs following exposure to as few as 1-10 bacteria and can result in both acute and chronic forms of disease. Infections can result in death, especially in the elderly or immunocompromised. Livestock, in particular sheep and goats, are the major source of human infections where infection can cause abortion, stillbirth and delivery of weak offspring. The loss of lambs and kids can result in devastating economic losses to the livelihoods of farmers in Europe as well as LMIC countries, particularly during abortion storms where up to 35% losses can occur.

Vaccines are currently considered the most effective way to control Q fever, and vaccines based on inactivated C. burnetii organisms are commercially available for use in both ruminants and humans. However, the safety of these vaccines is a major issue considering that severe local and systemic reactions occur post-vaccination in humans previously exposed to the bacteria and vaccination of ruminants is associated with significant production losses. Furthermore, manufacture of these vaccines involves culture of the organisms, which has both cost and safety issues. These issues have resulted in limited use of these vaccines. There is therefore an urgent need to develop safe, effective and easily manufactured vaccines to control Q fever in both humans and livestock species.

To this end, attempts have been made to develop subunit vaccines targeting key C. burnettii proteins which would be safer to manufacture and could be engineered to induce fewer side effects following vaccination. However, current approaches to subunit vaccine development have been severely hampered by a lack of knowledge of the appropriate bacterial proteins to target.

In this project, we will use novel peptide chip array technology to identify the key C. burnetii proteins recognised by antibodies from sheep and goats vaccinated with the current protective, but unsafe commercial vaccine in a high throughput and detailed manner. These antibody responses will be compared with those generated by a non-protective C. burnetii vaccine which is based on a different (non-virulent) form of the bacteria. By comparing antibody responses from protected and non-protective vaccines, bacterial proteins which are specifically targeted by the protective vaccine will be identified. Synthetic versions of these proteins will then be generated and subunit vaccines based on pools of these proteins will be tested in a sheep challenge model. This will provide preliminary safety and efficacy data to inform future Q fever vaccine development programmes.

Technical Summary

Q fever vaccines based on formalin inactivated phase I C. burnetii are protective but have considerable safety issues, both in terms of their manufacture and post-vaccination reactions. Vaccines based on the avirulent inactivated phase II C. burnetti are safer but non-protective. The aim of this project is to identify C. burnetii protein antigens which contribute to the protection induced by the phase I vaccine in order to rationally design a safe subunit Q fever vaccine.

To do this we will use novel high-density peptide chip arrays representing all open reading frames of the C. burnetii vaccine strain (strain RSA493) in 15-mer overlapping peptides. Pooled serum from sheep and goats vaccinated with the phase I vaccine will be used to probe peptide chips to identify antibody reactive peptides. Positive peptide hits from pooled serum samples will be validated at the individual animal level by ELISA using individual peptides. Pooled serum samples from sheep vaccinated with the phase II vaccine as well as samples from sheep, goats and humans exposed to C. burnetii will also be examined to identify peptides which are uniquely recognised by serum from individuals vaccinated with phase I but not phase II vaccines, and those unique to serum from exposed individuals (potential DIVA targets).

Once we have identified a panel of peptides which are associated with the protective vaccine, we will infer the protein target of peptide by comparison with the C. burnetii strain RSA493 genome, and select proteins which are recognised by all phase I vaccinated individuals. Proteins will be further selected based on known importance for C. burnetii virulence-related functions and sequence conservation between C. burnetii strains. The final pool of proteins will be synthesised as E. coli recombinant proteins. Prototype vaccines based on pools of these recombinant proteins will be tested for safety, immunogenicity and efficacy in a pregnant sheep C. burnetii challenge model.

Planned Impact

Who might benefit from this research?

At sequential stages of the project, scientists involved in vaccinology; commercial and non-profit vaccine manufacturers and distributors in developed countries and Low to Middle Income Countries (LMICs); livestock producers and meat industry workers (veterinarians, farmers, stockmen, dairymen, abattoir workers, animal transport workers, animal traders) in developed countries and LMICs worldwide; populations of humans living in close proximity to animals where agriculture and animal husbandry are significant sources of income.

How might they benefit from this research?

Scientists involved in vaccinology will benefit directly from the novel approach to antigen identification and will receive novel information on these processes via our Pathways to Impact, which may have direct downstream impact on their approach to vaccine production for a range of other viral, bacterial and multi-cellular pathogens. Vaccine manufacturers and distributors will benefit by having a safe, effective, easy to manufacture product which is also easy to store and administer. Coxiella burnetii infection in domesticated livestock has been associated with abortions, especially in sheep and goats, and infertility in cattle and therefore can have a profound economic impact on production worldwide[1]. The availability of a novel, cost-effective and protective vaccine for use in animals therefore benefits livestock producers but also helps to protect veterinary and agricultural workers by limiting their exposure to the pathogen, resulting in increased productivity and quality of life [2]. The potential public health benefits of an effective livestock vaccine can be illustrated by the 2007-2010 Q fever epidemic in the south-east Netherlands where >3000 cases of Q fever were notified in that short period. In this scenario, only ~3% of patients worked in the agricultural sector and only 0.5% worked in the meat-processing industry but the geographical area of the epidemic was densely populated and intensively farmed with dairy goats, resulting in the suspected transmission of contaminated dust from Coxiella-infected goats to humans living close-by [3]. Control measures including mandatory vaccination and culling on infected farms brought the epidemic to an end.

References
[1] Stark et al. Schweizer Archiv fur Tierheilkunde 139, 343-353.
[2] Kermode et al., Aust N Zealand J Public Health, 27, 390-398.
[3] Dijkstra et al. Immunol Med Microbiol 64, 3-12.

Publications

10 25 50
 
Description Through this project we have determined that the currently available Q fever vaccine (Coxevac) is protective against challenge with Coxiella burnetii (the causative agent of Q fever) for the first time. Furthermore the vaccine did not induce significant injection site or systemic reactions following vaccination in sheep. This provides supportive evidence that the vaccine can be deployed to sheep in the field to effectively control Q fever without inducing significant side effects.

We have also revised the genome of the current C.burnetii strain of bacteria which is used in the Coxevac vaccine and have identified another 400 potential genes (and therefore proteins) within C. burnetii genome. This allowed us to develop a method to identify the C. burnetii proteins targetted by the vaccine, which may be responsible for its protective effect.
Exploitation Route The results of this project to date may be used to facilitate deployment of currently licensed Q fever vaccines in the field. Identification of C. burnetii proteins targetted by the currently licensed Q fever vaccine will allow the development of the next generation of Q fever vaccines for use in animals and humans based on synthetic versions of these proteins.
Sectors Agriculture, Food and Drink,Education,Healthcare

 
Description Quantitative and qualitative analyses of cellular responses to Coxevac vaccine in sheep
Amount £157,266 (GBP)
Organisation Ceva Sante Animale 
Sector Private
Country France
Start 03/2020 
End 08/2020
 
Title Coxiella burnetii ruminant challenge model 
Description Through this project we have established a Coxiella burnetii challenge model in pregnant sheep.This is the only large animal model of C. burnetii infection in the UK. The model involves the challenge of pregnant ewes at 100 days of gestation with 10^6 infectious mouse dose equivalents of C. burnetii nine mile strain via the sub-cutaneous route within the Moredun High Security Unit, and evaluating pregnancy outcome and bacterial shedding during the periparturient period. As C. burnetii is a hazard group 3 pathogen this work has involved approval by the Health and Safety Executive as well as development of detailed health surveillance protocols for staff working on the project. 
Type Of Material Model of mechanisms or symptoms - mammalian in vivo 
Year Produced 2019 
Provided To Others? No  
Impact This model has allowed us to test the efficacy of C. burnetii vaccines in an appropriate animal host (i.e. ruminants). The data generated from the first study will be used to refine the model to ensure that appropriate numbers of animals are used in subsequent studies, in line with the principles of the 3Rs - Replacement, Reduction and Refinement. 
 
Title High-throughput peptide ELISA 
Description A 384-well peptide ELISA has been developed using a liquid handling robotics platform to allow high-throughput screening of serum samples for peptide-specific antibody binding. 
Type Of Material Technology assay or reagent 
Year Produced 2019 
Provided To Others? No  
Impact This assay has allowed the rapid validation of peptide antibody binding results from genome wide peptide arrays. This work has allowed us to select specific Coxiella burnetii proteins for inclusion in a prototype protein subunit vaccine. 
 
Description CEVA collaboration on Q fever vaccines 
Organisation Ceva Sante Animale
Country France 
Sector Private 
PI Contribution The project team has presented project data to CEVA under a confidentiality agreement. Reagents from sheep which were vaccinated against Q fever as part of this project were provided for a related CEVA project.
Collaborator Contribution CEVA attended a project meeting at Moredun Research Institute in January 2020 to discuss potential collaboration on Q fever vaccination.
Impact Funding has been acquired to identify immune correlates of protection for the CEVA Q fever vaccine.
Start Year 2019
 
Description Q-GAPS consortium partnership 
Organisation Friedrich Loeffler Institute
Department Federal Research Institute for Animal Health
Country Germany 
Sector Academic/University 
PI Contribution Q-GAPS (Q fever GermAn Interdisciplinary Program for reSearch) is an interdisciplinary and unique consortium is committed to investigate unsolved questions relating to the epidemiology, immunology, pathogenesis, surveillance and control of Coxiella burnetii. We have presented project data to the Q-GAPS consortium members in Glasgow (Septeimber 2019) which has resulted in an invitation to present at the Q-GAPS consortium meeting in Munich.
Collaborator Contribution Q-GAPS partners have organised a consortium meeting in Munich (March 2020) at which the PI from this grant (Dr Tom McNeilly) will present.
Impact Initial outcomes have centred around knowlegde exchange, with a view to collaborating on Q fever vaccination and diagnostics with members of the Q-GAPS consortium.
Start Year 2020
 
Description Accelerated development of a safe and easily manufactured Q fever vaccine 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact A poster was presented at the UK & International Veterinary Vaccinology Network Conference 2019 in London, UK. The postier outlined the Q fever vaccine project and current progress on the first vaccination trial. This was attended by over 200 national and international researchers from North and South America, Africa, Asia and Australasia. The poster was awarded third prize and sucessfully instigated questions and discussions on the project. The meeting also allowed introductions to the African Vaccinology Network (AfVANET) coordinators to discuss potential future research collaborations.
Year(s) Of Engagement Activity 2019
URL https://drive.google.com/file/d/1RReamwdNnCoZZmNWZJeGtC6mApcyY9q_/view
 
Description IBAHCM seminar series talk: Ruminant bacterial zoonoses: pathogen diversity, immunity and vaccine interventions 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact An invited seminar was given by Tom McNeilly as part of the University of Glasgow Institute of Biodiversity, Animal Health & Comparative Medicine (IBAHCM) seminar series entitled: Ruminant bacterial zoonoses: pathogen diversity, immunity and vaccine interventions. Approximately 40 people attended the seminar, including a mixture of undergraduate, post-graduate students, research professionals and visiting researchers. The talk covered Q fever vaccination and the latest results from this project. A member of the audience was part of the German Q-GAPS consortium (https://www.q-gaps.de/en/) and as a result of this talk, a collaboration has now been established betweeen this project and the Q-GAPS consortium.
Year(s) Of Engagement Activity 2013,2019
URL https://www.gla.ac.uk/researchinstitutes/bahcm/about/events/instituteseminars/
 
Description International Veterinary Vaccinology Network Newsletter 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact An article was written for the International Veterinary Vaccinology Newsletter to promote the project. The article gave an overview of the project including background on Q fever and details of the programme of work. This resulted in a number of queries regarding potential collaborations on projects related to Q fever vaccines which are being actively pursued.
Year(s) Of Engagement Activity 2018
URL https://www.intvetvaccnet.co.uk/news/2018/10/researchers-awarded-funding-develop-improved-q-fever-va...
 
Description Moredun Magazine article: "New grant to develop improved Q fever vaccines" 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact An article was written for the Moredun Magazine Autumn/Winter 2019. This magazine is distributed to all Moredun Foundation members (>10,000). The article gave a background on Q fever and outlined the approach taken in the project to develop a safer Q fever vaccine. The article prompted questions and discussions to the project PI by members of the Moredun group board.
Year(s) Of Engagement Activity 2018
URL https://www.moredun.org.uk/publications/moredun-magazine
 
Description Open Access Government article: "Q fever: An emerging problem in LMIC and the need for improved vaccines" 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Policymakers/politicians
Results and Impact A magazine article was published in Open Access Government on Q fever: An emerging problem in LMIC and the need for improved vaccines. This article was targetted at policy makers/government agencies to highlight the increasing awareness of Q fever in LMIC countries and the need to develop safer and more easily manufactured vaccines. The article linked to the project (BB/R019975/1) and initiated contacts with potential collaborators in LMIC countries.
Year(s) Of Engagement Activity 2019
URL https://www.openaccessgovernment.org/improved-vaccines/62803/
 
Description Presentation at Moredun Research Institute External Science Review Day June 2020 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Professional Practitioners
Results and Impact The post-doctoral research scientist employed on the project, Dr Sarah Williams-MacDonald, gave a talk on "Accelerated development of a safe and easily manufactured Q fever vaccine". This talk gave an update on the project results up to June 2020.
Year(s) Of Engagement Activity 2019
 
Description Presentation at the 73rd Annual Association for Veterinary Teachers and Research Workers Conference 2019 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Postgraduate students
Results and Impact A short talk and poster presentation was given at this meeting on the Q fever project by the post-doctoral research scientist employed on the project. Approximately 40 people attended the conference, mainly post-graduate research scientists from the UK veterinary research community. The talk and poster initiated discussions on existing Q fever vaccines and how these can be improved in terms of safety of manufacture and use.
Year(s) Of Engagement Activity 2019
URL http://www.avtrw.co.uk/past-events/2019/
 
Description The contribution of livestock to food production, biodiversity and the environment - Open Day in the presence of HRH The Princess Royal 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact An open day event was held on 21st October 2019 at the Moredun Research Institute on 'The contribution of livestock to food production, biodiversity and the environment'. The Q fever vaccine project was presented to HRH The Princess Royal and her visiting group and the project aims and outputs discussed. A total of 114 people attended the meeting including invited members of the general public, farmers, veterinarians, scientists, undergraduate and postgraduate students. The presentation sparked discussions on the current state of Q fever vaccines and how they can be improved.
Year(s) Of Engagement Activity 2019
URL https://www.moredun.org.uk/news/press-release-princess-royal-visits-moredun-highlight-contribution-l...