Transmissible Cancers and Immune Downregulation in Tasmanian Devil (Sacrophilus harrisii) and Canine Populations.

Transmissible Cancers and Immune Downregulation in Tasmanian Devil (Sacrophilus harrisii) and Canine Populations. Comp Med. 2019 Aug 06;: Authors: Chale RS, Ghiam N, McNamara SA, Jimenez JJ Abstract Known as devil facial tumor disease (DFTD) and canine transmissible venereal tumor (CTVT), transmissible cancer occurs in both Tasmanian devil and canine populations, respectively. Both malignancies show remarkable ability to be transmitted as allografts into subsequent hosts. How DFTD and CTVT avoid detection by immunocompetent hosts is of particular interest, given that these malignancies are rarely seen in other species in nature. Both of these transmissible cancers can downregulate the host immune system, enabling proliferation. DFTD is characterized by epigenetic modifications to the DNA promoterregions of β2 microglobulin, transporters associated with antigen processing 1 and 2, MHC I, and MHC II-crucial proteinsrequired in the detection and surveillance of foreign material. Downregulation during DFTD may be achieved by altering the activity of histone deacetylases. DFTD has caused widespread destruction of devil populations, placing the species on the brink of extinction. CTVT demonstrates a proliferative phase, during which the tumor evades immune detection, allowing it to proliferate, and a regressive phase when hosts mount an effective immune response. Alteration of TGFβ signaling in CTVT likely impedes the antigen-processing ...
Source: Comparative Medicine - Category: Zoology Authors: Tags: Comp Med Source Type: research