The role of plasminogen and tPA in prion disease is further clouded by divergent results when plasminogen deficient animals (plg−/−) were inoculated with prion disease: one study reports a very slight protection of plg−/− animals (Salmona et al.,2005), while the other reports that plasminogen deficiency prompts earlier symptoms and death (Xanthopoulos et al.,2005). Here, PLG is linked to prion disease.