The results of an international study published recently in Scientific Reports has confirmed the fatal facial tumour disease that has decimated populations of Tasmanian devils in the wild for over 20 years, can be cured using immunotherapy.
Led by the University of Tasmania’s Menzies Institute for Medical Research, the study involved scientists from the Universities of Sydney, Southampton, Southern Denmark and Cambridge, as well as those from UTAS’s School of Medicine, the Walter and Eliza Hall Institute of Medical Research, and CSL Ltd.
The aim of the study was to ‘explore immunisation protocols to enhance protective responses against DFTD’, but due to devils’ endangered status, only a limited number of animals are available for research purposes. This five-year trial, that tested four immunisation protocols sequentially, was therefore restricted to nine healthy and genetically different animals, some of which had reached an advanced age.
“Seven devils were immunised with a variety of cell preparations and adjuvants to determine if they could be protected against the development of DFTD following challenge with live DFTD cells. One devil was used as an adjuvant-alone control, and one devil as a non-immunised control,” the report stated.
In a technique described as ‘fighting cancer with cancer’ by UTAS Professor of Immunology Greg Woods, six of the immunised devils and the non-immunised control devil were later challenged with live DFTD cells that had been cultured in the laboratory. If the devils developed tumours, immunology commenced and tumour rejection and anti-tumour antibody responses in the animals were measured.
Co-author, and senior member of the Save the Tasmanian Devil Team Bruce Lyons, from the School of Medicine, said while previous studies had demonstrated devils responded to immunisation, there was no evidence vaccination prevented tumour regrowth, although an earlier study had shown a substantial delay in tumour regrowth, (The Veterinarian, March 2015).
Over a three-month period golf-ball sized tumours were shown to gradually shrink and disappear, allowing researchers to claim with certainty it was immunotherapy that caused the shrinkage.
Building an understanding of the devil’s immune system goes hand in hand with the development of a vaccine, and involves years of painstaking laboratory work. Although the process is incremental, Lyons said that with each step scientists are closing in on the disease.
“Now that we have a better way of getting a good immune response we’re looking at using live cells as a vaccine. There are a few hurdles to doing that – we don’t want to end up giving a tumour to an animal for example – but if we have a cell line, or lines, that are controllable then vaccination is going to much more effective. The main take-home story from this study is we have proof something’s happening with DFTD cells that we can translate into a much more effective vaccine,” he said.
The research was funded by the Australian Research Council, the National Health and Medical Research Council, and the Wellcome Trust, with additional support from the University of Tasmania Foundation through funds raised by the Save the Tasmanian Devil Appeal.
Anne Layton-Bennett
‘Regression of devil facial tumour disease following immunotherapy in immunised Tasmanian devils’ is available online.