The Nobel Prize in medicine has been awarded to Stanley Prusiner, who has tirelessly championed the idea that infectious proteins can cause brain diseases such as Creutzfeldt-Jakob syndrome, scrapie, and mad cow disease. The Karolinska Institute announced this morning that the University of California, San Francisco, neurologist had won the prize "for his discovery of prions, a new biological principle of infection."
Prusiner coined the term "prions" in 1982 to describe the "proteinaceous infectious particles" that many scientists now believe cause disease by misfolding and recruiting other proteins to do likewise. The idea that a protein acting alone--without DNA or RNA--could transmit disease was heretical when Prusiner began promoting it. Since then, the theory has gained support from experiments by Prusiner and others, which reported that a protein called PrP changes shape in the brains of diseased animals and that the protein is crucial to infectivity.
Scientists in the field say both his experiments and his tireless defense of the theory have had an important impact. In a statement, Charles Weissmann of the University of Zurich wrote, "Prusiner is a true pioneer and iconoclast, and fully deserves the Nobel Prize he has been awarded."
However, many scientists say that there is not yet final proof that prions can cause disease by themselves: No one has been able to inject the purified protein into a healthy animal and make it sick. "I think it's speculation that the protein itself is infectious," says Laura Manuelidis, a neuropathologist at Yale University who has argued that a virus or other particle is involved in the prion process. "I hope [the award] won't stop people from trying to find out the definitive data for what the agent is."
[See Prusiner's Article, "Prion Diseases and the BSE Crisis ," in the current issue of Science.]
[Also see the 12 July 1996 issue of Science for a Special News Report  on prions.]