Due to the facial tumor disease, Tasmanian devil population falls to 50,000 from 1, 50,000.
They’re inky black, pointy-eared, furry and, in a fierce sort of way, cute. And in May of this year, they were added to Australia’s endangered species list. Ordinarily solitary, Tasmanian devils commune only to feast on carrion and to mate in short-lived assonate couplings during which they tear each other to ribbons. Their spine-decalcifying caterwauls – a sequence of whiffing, snarling and growing – have evoked satanic visions since the first European settlers arrived on the island of Tasmania more than century ago.
The Tasmanian devil has been trapped in a purgatory of its own. Since 1996, a deadly cancer, devil facial tumor disease, has preyed on the devil. Its population plummeted to fewer than 50,000 from about 1, 50,000 said Dr.Hamish Mc Callum, senior scientist with the Devil Facial Tumor Disease Programmed at the University of Tasmania. The devils’ situation is dire. Yet as more has been learned about the disease, hope has appeared. Scientists have begun an experimental inoculation programmed, and this year, Dr. Woods identified one devil able to mount an antibody response to the tumor.
The devil, Cedric, is a 3-year-old male from western Tasmania who has been living in captivity for several months. Dr.Woods inoculated Cedric and his half-brother, Clinky, who was also disease-free at the time, with irradiated – that is, dead – devil tumor cells. Although they had the same mother, Cedric and Clinky had different fathers. Dr. Woods repeated the vaccination three times. He then administered live tumor cells to both. Cedric mounted an immune response and lived. Clinky did not develop an immune response, and he succumbed to the cancer. His father’s genetic made Clink’s immune system more like that of the devils found in eastern Tasmania.
All mammalian immune systems rely on certain cells to recognize invaders. Demarcation of “otherness” at the cellular level is carried out in a part of the mammalian genome called the major histocompatibility complex, or MHC. An animal’s ability to fight of disease depends on this group of genes. MHC is responsible for the cell markers that flag the difference between cells that are “self’ and those that are “non-self.” But the tumor’s MHC is what makes it deadly to the devil. “The tumor has no foreign cell surface markers,” said Dr.Katherine Belov, a scientist in the Australasian Wildlife Genomic Group at the University of Sidney. “If tumor cells get into a devil, its own immune system should be able to see the cells as foreign. That doesn’t happen because the tumor’s cells look like devils’ own cells.” She said.
Dr.Belov likened the process to genetic matching for an organ transplant.
