UCSF-led researchers have developed a highly sensitive, automated test for detecting prions (PREE-on) that they report significantly improves the accuracy and speed of detecting the various forms of the infectious agent, which causes a set of neurodegenerative diseases, in cattle, sheep, deer and elk.
Because the test is automated, the researchers say, it could be used for high-throughput testing of brain samples of cattle with bovine spongiform encephalopathy (BSE), or "mad cow" disease, as well as deer and elk with chronic wasting disease (CWD).
The test, an immunological probe, or "immunoassay," 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.
The high sensitivity of the test in detecting BSE and CWD prions, reported in the October 21 on-line version of Nature Biotechnology, culminates an effort to perfect the application of a principal that the UCSF team firsts reported in 1998 in a study in hamsters.
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 immunological procedures. Those older methods, which detect only fragments of infectious prion protein that are resistant to an enzyme known as protease, are currently used in the United Kingdom and Europe to detect prion-infected brain in cattle.
The new test in fact matches the sensitivity of what is currently the most reliable technique for determining the level of prion infectivity in a tissue. This bioassay, which has a time lag that makes it impractical for the rapid detection of prions in large-scale testing in tissue, involves injecting brain tissue from cattle with BSE into mice geneti
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Contact: Jennifer OBrien
jobrien@pubaff.ucsf.edu
415-476-2557
University of California - San Francisco
20-Oct-2002