Prevention of TSE (Transmisible Spongiform Encephalopathies) with synthetic peptides: influence on progression of disease.

Prion diseases are neurodegenerative disorders characterized by protein misfolding and extracellular deposition of pathological proteins. Therapeutic studies on these conformational disorders place great emphasis on immunotherapy. In the current study immunization with two peptides was performed in Syrian Golden hamsters. The effect of immunization of the animals at different stages of scrapie infection was studied. Fourteen Syrian Golden hamsters were divided into two groups and immunized with the synthetic peptides PrP 119–146 and PrP 142–179, conjugated to carriers, respectively. Animals were infected intraperitoneally with the scrapie strain 263 K (105ID50) and killed at the onset of symptoms. Positive and negative control groups were also included. Brain from all animals were analyzed for spongiform lesions, PrPres deposits and astrocytosis and PrPres was evaluated in all spleen samples. Results showed that immunization with peptide PrP 119–146 slowed down and limited the neurodegenerative processes induced by prion diseases, as well as neuroinflammation. Immunization slightly reduced PrPres deposition in the central nervous system and seemed to slow down the progression of PrPres during peripheral pathogenesis. Once PrP had reached the brain, immunization did not prevent death. Our results indicated that immunization against TSE with synthetic peptides only had a prophylactic function.