Bovine tuberculosis is a serious problem in many parts of the world, resulting in the culling of thousands of cattle each year and at tremendous cost. Now, Chinese scientists have produced a herd of transgenic cows that exhibit an improved ability to ward off the disease.
Cattle that were genetically modified to carry a mouse gene called SP110 were reportedly "more difficult to infect and are largely shielded from the damaging symptoms" of bovine tuberculosis. What's more, the new gene did not appear to have any effect on the activity of the cattle's normal gene function, nor was it found to be heritable. As The Guardian reports:
In the latest study, published in the journal Proceedings of the National Academy of Sciences, scientists from the Chinese agriculture ministry created 23 genetically modified calves, 13 of which survived into adulthood. The team used a gene editing tool, known as TALEN, which allows scientists to delete naturally occurring genes and insert new ones with a high degree of precision.
In laboratory tests, they showed that the Mycobacterium bovis bacterium, which causes TB, multiplied far less effectively in the presence of immune cells taken from the GM cattle, which had been given a mouse gene that was known to be protective against TB.
The scientists deliberately introduced the TB bacteria into the lungs of three of the GM cattle and three control cattle and compared the effects. One of the GM cattle showed no sign of the illness and the other two showed far fewer lesions than the control cattle in their lungs, spleen and liver, when they were dissected several weeks later.
A second test also produced encouraging results.
This is the first study to show that transgenic cattle, with the help from mice, can acquire resistance to bovine TB — one that could result in other GM farm animals automatically protected from diseases.
Image: Keith Weller/U.S. Department of Agriculture/CC