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Published on: 6/27/2003
Last Visited: 7/9/2006
At the University of Kentucky, for example, Glenn Telling, PhD, associate professor of microbiology, immunology, and molecular genetics, is making transgenic mice that express cervid (deer or elk) PrP, and also chimeric forms between mouse and cervid.At this point, he and his colleagues are waiting to see when the inoculated mice will develop disease.
They're also interested in the mechanism of prion propagation, which involves using cell culture in vitro approaches as well as transgenic models.Currently Dr. Telling is studying the post-translational processing of PrPc (the normal form of the prion protein) and PrP scrapie (the abnormal form)."It's clear they're very different," he says."So we're trying to define these processing events in the infected and uninfected states."He and his colleagues have recently discovered an enzyme group called calpains, which are calcium-activated cysteine proteases and cleave the scrapie form of PrP."We think this is a major advance," he says."It could open up new therapeutic avenues for inhibiting prion propagation, because if we can inhibit calpains that cleave PrP scrapie, then we can possibly abrogate prion disease.But," he acknowledges, "we need to do a lot of work in vivo to substantiate that, and that's what we're doing at the moment."
Other therapeutic possibilities are more developed, especially immunotherapies.Researchers have developed specific antibodies against PrP and demonstrated, in vitro and in animal models, that certain antibodies can inhibit prion replication."They've shown they could treat animals with specific monoclonal antibodies peripherally, at least, and inhibit the development of clinical features of prion disease," Dr. Telling says.
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Indeed, along with Drs. Gambetti, Telling, and others, he's well versed in the devilish nature of prions.
"Usually when you study how virus or bacteria behaves in the environment, you're looking at a fairly well-defined entity," he says.