Did you hear the news? They finally proved that prions cause TSE. Oh, you thought they already proved that didn't you? They gave the guy a Nobel Prize, after all. Well, he not only failed to prove it before, he still hasn't proved it.
Here's the deal: if you take prions from a tse-ridden brain, purify them, and inject them directly into someone else's brain (say, a mouse), they don't get the disease. In the latest experiment, they finally got some mice to get sick from these injections. The first problem is that the shit they injected was modified into amyloid plaques in advance, so they certainly didn't prove that prions spontaneously form these plaques of their own accord. Furthermore, the supposedly unique prion strain that resulted looks surprisingly familiar:
Dr. Laura Manuelidis, a neuropathologist at the Yale University Medical School, one of Dr. Prusiner's most vocal critics, said the prion strain that turned up in the experiment looked like a mouse prion frequently used in Dr. Prusiner's laboratory. She said that meant that something else might have caused the infection. "Basically I think the data look like contamination," Dr. Manuelidis said, possibly stemming from "inadequately washed instruments.''And then there's another small problem: the mice in question were genetically modified to produce prions all by themselves. [NYT story, ScienceNOW story, Science paper]