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Post-release immune responses of Tasmanian devils vaccinated with an experimental devil facial tumour disease vaccine

Citation

Pye, RJ and Darby, JM and Flies, AS and Fox, S and Carver, SS and Elmer, J and Swift, KR and Hogg, C and Pemberton, D and Woods, GM and Lyons, AB, Post-release immune responses of Tasmanian devils vaccinated with an experimental devil facial tumour disease vaccine, Wildlife Research, 48, (8) pp. 701-712. ISSN 1035-3712 (2021) [Refereed Article]


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DOI: doi:10.1071/WR20210

Abstract

IContext: Disease is increasingly becoming a driver of wildlife population declines and an extinction risk. Vaccines are one of the most successful health interventions in human history, but few have been tested for mitigating wildlife disease. The transmissible cancer, devil facial tumour disease (DFTD), triggered the Tasmanian devil's (Sarcophilus harrisii) inclusion on the international endangered species list. In 2016, 33 devils from a DFTD-free insurance population were given an experimental DFTD vaccination before their wild release on the Tasmanian northern coast.

IAim: To determine the efficacy of the vaccination protocol and the longevity of the induced responses.

IMethod: Six trapping trips took place over the 2.5 years following release, and both vaccinated and incumbent devils had blood samples and tumour biopsies collected.

IKey results: In all, 8 of the 33 vaccinated devils were re-trapped, and six of those developed DFTD within the monitoring period. Despite the lack of protection provided by the vaccine, we observed signs of immune activation not usually found in unvaccinated devils. First, sera collected from the eight devils showed that anti-DFTD antibodies persisted for up to 2 years post-vaccination. Second, tumour-infiltrating lymphocytes were found in three of four biopsies collected from vaccinated devils, which contrasts with the 'immune deserts' typical of DFTs; only 1 of the 20 incumbent devils with DFTD had a tumour biopsy exhibiting immune-cell infiltrate. Third, immunohistochemical analysis of the vaccinated devils' tumour biopsies identified the functional immune molecules associated with antigen-presenting cells (MHC-II) and T-cells (CD3), and the immune checkpoint molecule PD-1, all being associated with anti-tumour immunit 1000 y in other species.

IConclusions: These results correlate with our previous study on captive devils in which a prophylactic vaccine primed the devil immune system and, following DFTD challenge and tumour growth, immunotherapy induced complete tumour regressions. The field trial results presented here provide further evidence that the devil immune system can be primed to recognise DFTD cells, but additional immune manipulation could be needed for complete protection or induction of tumour regressions.

Implications: A protective DFTD vaccine would provide a valuable management approach for conservation of the Tasmanian devil.

Item Details

Item Type:Refereed Article
Keywords:devil facial tumour disease, transmissible cancer, vaccine, immunohistochemistry
Research Division:Biological Sciences
Research Group:Biochemistry and cell biology
Research Field:Cell development, proliferation and death
Objective Division:Health
Objective Group:Clinical health
Objective Field:Diagnosis of human diseases and conditions
UTAS Author:Pye, RJ (Ms Ruth Pye)
UTAS Author:Darby, JM (Ms Jocelyn Darby)
UTAS Author:Flies, AS (Dr Andy Flies)
UTAS Author:Carver, SS (Associate Professor Scott Carver)
UTAS Author:Woods, GM (Professor Gregory Woods)
UTAS Author:Lyons, AB (Associate Professor Bruce Lyons)
ID Code:152080
Year Published:2021
Deposited By:Menzies Institute for Medical Research
Deposited On:2022-08-11
Last Modified:2022-08-11
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