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Stanley Prusiner photo


Dr. Stanley Prusiner, who took his undergraduate degree in chemistry from the College and an M.D. from Penn Med, has been awarded the Nobel Prize in medicine for his work in discovering the agent that may cause such brain diseases as Mad Cow and Creutzfeldt-Jakob disease. The Nobel Assembly cited Prusiner for his discovery of the prion (PREE-on), a rogue protein that is totally unlike anything else previously known to cause infectious disease.

Prusiner was the first researcher to suspect that a protein, which does not contain the genes or genetic material that allows viruses and bacteria to reproduce themselves, could cause disease. The idea was immediately controversial -- so much so that many in the scientific community dismissed Prusiner and his work as heretical. As Dr. Britton Chance, emeritus professor of biochemistry and biophysics explains, "Nobody believed in the existence of prions for many years, but with his dogged persistence and wonderful integrity he went on until he unlocked the cause of Mad Cow Disease and the rest of the prion diseases."

It was only the fifth time since 1960 that the Nobel Prize for medicine was awarded to an individual instead of a group. Prusiner's research was done at the University of California at San Francisco. He will receive $1 million when he attends the award ceremony in Stockholm on December 10.

Prusiner began his work in 1972 when one of his patients died of Creutzfeldt-Jakob Disease (CJD), a form of dementia resulting from brain disease. Previous work had shown that similar brain diseases such as kuru and scrapie, a disease affecting sheep, could be transmitted by introducing extracts of an infected brain into a host. Prusiner began his work to identify the infective agent in these diseases and, in 1982, identified the agent as a single protein. He named the protein a prion, an acronym for proteinaceous infectious particle.

Prions are a natural part of human and animal brains and, in their normal form, cause no problems. What Prusiner found was that they occasionally change shape and, with this change, the prions become defective and begin to work at changing others into this destructive form. When this happens in the brain, entire pockets of brain tissue eventually die as they accumulate abnormal proteins.

In addition to the existence of prions, Prusiner also showed how these diseases can be passed from one species to another. There is strong evidence that new cases of Creutzfeldt-Jakob discovered in Europe are the result of people eating beef from cows with Mad Cow Disease. When the disease is passed from animal to animal, it is often from feeding cows, for example, with the offal of sheep who were infected with scrapie.

The implications of Prusiners discoveries are being applied to the search for the cause of Alzheimer's disease. Alzheimer's is distinguished by deposits of a plaque called beta amyloid, an insoluble form of a protein that normally appears in the brain. The scientific community is now considering whether some prion-like process is involved in changing the amyloid from its normal state into the plaque state.

Prusiner's list of awards is distinguished and long, and includes prizes from the American Academy of Neurology, the NIH, the National Academy of Sciences, and the Fairdner Foundation Award for Outstanding Achievement in Medical Science -- widely considered to be a predictor of the Nobel. In 1991, he received the Distinguished Alumnus Award from the University's Medical School. Upon receiving the award Prusiner told Penn Medicine, "Britton Chance gave me an extraordinary opportunity to pursue an interest in adipose tissue....And I keep wondering today whether, if someone came to me with such a crazy idea, I would let them pursue it in my laboratories." The editors of Penn Medicine believe that this remark was made tongue-in-cheek because he is known for recruiting junior investigators and stimulating them as they start scientific careers.

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