Detection of PrPres in the spleen of hamsters used as an in vivo model for experimental TSE

In order to detect the presence of PrPres in the spleen of infected hamsters, we used a newly developed extraction method, before Western blot analysis, allowing the precipitation of PrPres. The NaPTA treatment applied before proteolysis causes a change in the PK cleavage site, resulting in the generation of larger PrPres fragments, acting on the N-terminal region of PrPres. By using this procedure, with some modifications, we succeeded in detecting the prion protein in the spleen and obtained the expected bands of prion protein, while in previous reports only very weak signals were obtained. Moreover, it was possible to confirm that the amount of detectable PrPres in the hamster spleen is very low, suggesting that the spleen plays a non-essential role for development of the disease in the hamster experimental model.