PrP^TSE-associated seeding activity in muscles from CWD-infected WTD.

<p>Western blot detection of Proteinase K-resistant prion protein (PrPres) after PMCA. For PMCA normal hamster brain homogenate was seeded with 10 µl of a 10% (w/v) CWD brain homogenate from an infected WTD (A), or with PrP^TSE-extract from <i>M. semimembranosus/tendinosus</i> of a CWD-infected WTD (Fa-WTD 1, B). In (C) PMCA was seeded with <i>M. semimembranosus/tendinosus</i> from Fa-WTD 2 that had been tested positive for PrP^TSE in brain tissue while no PrP^TSE could be detected by Western blotting in muscle extracts of this animal (the negative result with this muscle is shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0018345#pone-0018345-g002" target="_blank">figure 2</a>, lane 8). (D) Unseeded control in which PMCA was performed with normal hamster brain homogenate only. Lanes 1–7 represent Western blot findings after 1, 2, 3, 4, 5, 6 and 7 rounds of PMCA. Lane 8, Proteinase K-digested brain homogenate from a hamster in the clinical stage of scrapie representing 1×10⁻⁷ g of hamster brain tissue (loaded as an internal blotting control). M: molecular mass marker. Anti-PrP monoclonal antibody 3F4 was used as primary antibody for the detection of PrPres.