Test Improves Detection of Prions in Animals

Researchers have developed a highly sensitive, automated immunoassay for detecting prions that significantly improves the accuracy and speed of detecting the infectious agent that causes a set of neurodegenerative diseases in cattle, sheep, deer and elk. The test also has the potential to test people for Creutzfeld-Jakob disease (CJD), the human version of mad cow disease. The development of the test was reported in the October 21 online version of Nature Biotechnology.

Because the test is automated, it could be used for high-throughput testing of brain samples of cattle with bovine spongiform encephalopathy (BSE, also known as mad cow disease), as well as deer and elk with chronic wasting disease (CWD). An immunologic probe, the test uses a novel strategy and newly developed, high-affinity antibodies to reveal and measure prions in brain tissue. As a result, it is able to directly measure infectious, abnormal prion protein. In 1,729 tests, the test correctly identified samples of diseased and normal tissue with 100 % accuracy.

Known as a conformation-dependent immunoassay (CDI), the test is able to detect much smaller levels of the infectious prion protein than can be seen with the current standard immunologic procedures. The test was developed by researchers at the University of California, San Francisco, Institute for Neurodegenerative Diseases (UCSF, USA; www.ucsf.edu).

"The conformation-dependent immunoassay essentially lowers the threshold for detection of bovine spongiform encephalopathies,” says the lead author of the study, Jiri Safar, M.D., UCSF associate adjunct professor of neurology. "We believe that by applying the test to cattle we should significantly reduce human exposure to bovine prions.” More broadly, Dr. Safar believes the CDI could be applied to studies of other neurodegenerative diseases, such as Alzheimer's disease, and could potentially be used to diagnose patients with Creutzfeldt-Jakob disease.




Related Links:
Univ. of California, San Francisco