Even as scientist Stanley B. Prusiner was accepting a Nobel prize in 1997 for linking misfolded proteins to certain brain diseases, doubters were pointing out that no one had ever actually shown that these proteins—which Prusiner dubbed prions—could cause infection.
Prusiner, a neurologist and biochemist at the University of California, San Francisco (UCSF), and his colleagues now report results that could silence many of his critics. The study, published in the July 30 Science, shows that purified prions can cause disease when injected into the brains of genetically engineered mice.
Previous work by Prusiner and others had implicated prions in human-brain ailments that include Creutzfeldt-Jakob disease and kuru, as well as mad cow disease, chronic wasting disease in deer and elk, and scrapie in sheep.
Suggesting that proteins, misfolded or not, can be infectious is "a radical notion," says Neil R. Cashman of the University of Toronto. Neverth