In vitro generation of infectious scrapie prions
Authors: Claudio Soto
Claudio Hetz
Paula Saá
Joaquín Castilla
Journal: Cell (2005)
Discipline: MOLECULAR BIOLOGY & GENETICS
Keywords: Prions; transmissible spongiform encephalopathy; TSE diseases; protease-resistant prion protein; PrPres
Affiliations: Department of Neurology, University of Texas Medical Branch, Galveston, Texas 77555, USA.

Abstract:  Prions are unconventional infectious agents responsible for transmissible spongiform encephalopathy (TSE) diseases. They are thought to be composed exclusively of the protease-resistant prion protein (PrPres) that replicates in the body by inducing the misfolding of the cellular prion protein (PrPC). Although compelling evidence supports this hypothesis, generation of infectious prion particles in vitro has not been convincingly demonstrated. Here we show that PrPC --&gt; PrPres conversion can be mimicked in vitro by cyclic amplification of protein misfolding, resulting in indefinite amplification of PrPres. The in vitro-generated forms of PrPres share similar biochemical and structural properties with PrPres derived from sick brains. Inoculation of wild-type hamsters with in vitro-produced PrPres led to a scrapie disease identical to the illness produced by brain infectious material. These findings demonstrate that prions can be generated in vitro and provide strong evidence in support of the protein-only hypothesis of prion transmission. 

Retracted: No

PubPeer comments:
 Figure 1B. * Blue, orange, green, and red boxes focus attention to areas in the blot strips that show unexpected similarities. * Image made darker to bring out details. Would the authors still have the original blots to show? There might be a perfectly fine technical explanation, but I am just curious how such similarities in different parts of the blots could happen. ![file] , 
 #1 Hereu2019s an inverse version of that image. ![file] , 
 Maybe a detail: lane 10 seems to be divided left right with vertical limits occurring at slightly different X-positions below and above the middle band. I also see in the figure legend that lane 6 corresponds to Bartonella elizabethae: back in 2001, could the inclusion of this species in the setup have been an anticipated tribute to Dr Bik? , 
 Apparently there is a cabal of antiscientists currently active on PubPeer dedicated to undermining the pure science and the even purer motives of some outfit in Marseilles. Itu2019s been hampering their efforts to dose up COVID patients with HCQ. That is just so unfair. https: www.buzzfeednews.com article stephaniemlee elisabeth-bik-didier-raoult-hydroxychloroquine-study The intarwebs being what it is, the tweetosphere has inevitably plunged into the depths of a seemingly bottomless well of ordure. Trolls gotta troll. Aroused by all this hullaballoo, I couldnu2019t help but wonder whether the gel in Fig. 1A of this 2001 paper has been manipulated and republished from Fig. 1 of a 2000 paper. https: pubpeer.com publications CD0D28903FC0BC318E23D3DE3CBB86 The vertical artefacts in some of the lanes match up well. However, the whole gel cannot be superposed, in part due to internal splicing between some lanes. Vertically stretched, rotated and differently cropped it maybe too. Some lanes may have been flipped and repasted in position. Some lanes may have vertical smearing effects. Three additional lanes are also newly added at right. It is going to take lane-by-lane transparency superpositions to work through the similarities. May as well begin with lanes 10. ![image] Dr. Condy has been labouring under the misapprehension that new papers are supposed to have new data. Perhaps that is why it has not yet injected 3,168 publications into the scientific literature. Still, it is never too late to learn from oneu2019s peers out there. , 
 Next up the lanes 5 are superposed. Lanes 3 and 4 are shifted horizontally. Lane 6 in 2021 is not lane 6 in 2020 - weu2019ll come back to that later. ![image] , 
 It turns out that the 2020 Fig. 1 WB has already been reused in its entirety. Back in 2020. The same year it was first published. Unacknowledged. This observation may be appreciated at https: pubpeer.com publications 645E9E294197B90ED341981E263156 Regarding efforts at lane superpositioning, perhaps it might be better to invert greyscale for both WB images and then use RGB colour overlay as an estimate of band similarity. If one gel is now blue and the other is green, and one of them is 50% transparent, then the goal is to maximise what approximates as cyan. In this case for superposed lanes 3. Bearing in mind that Dr. Condy is a woody Amazonian plant that absorbs blue light but prefers to reflect green wavelengths, how did it manage? ![image] , 
 Since my last lane superpositioning effort, things seem to have all gone a bit pear-shaped down Marseillesu2019 way. https: www.leparisien.fr societe sante didier-raoult-accuse-davoir-falsifie-des-resultats-de-tests-pour-ses-travaux-lhopital-ouvre-une-enquete-interne-19-11-2021-XPFMQ52W75C67CYHNOHYL7TEBY.php *u201cPlus u00e7a change, plus c est la mu00eame choseu201d* Might the French establishment now get around to reviewing the way that u201cla recherche scientifiqueu201d has recently been conducted in that institutional mini-dictatorship? *u201cu00c0 la recherche du COVID-19 temps perduu201d* Optimist that I am, I hope to sign off on the admittedly rather more dull stuff here with this Lanes 1 superposition. That required a 2u00ba Rotation and the usual stretchiness. The temporally subsequent WB is inverted and set to 100% green colour channel. The original WB is inverted and set to 100% for both red and blue channels. Superposed elements should approximate to grey white. ![image] ,