Prions

Abstract

Prions are infectious proteinaceous particles that lack nucleic acid. These agents are responsible for fatal degenerative diseases of the central nervous system in a number of mammalian hosts including humans. Because prions are devoid of nucleic acids unlike other pathogens, they are incapable of reproduction but can self-propagate through the mechanism of protein misfolding. The misfolded protein associated with transmission of disease is a conformationally altered isoform of host-encoded cellular prion protein (PrPC) termed PrPSc. Since PrPSc is resistant to the treatment sufficient to abolish genetic material included in other agents, prions composed of this aberrantly folded isoform of prion protein can not be inactivated by conventional sterilization methods. Studies conducted during the last several decades have provided the information that can resolve the mystery of the nature of prions and unconventional characteristics of prion transmission. In this chapter, we summarize the discovery of prions and the current knowledge of their composition, structure, and replication. © 2011 Nova Science Publishers, Inc. All rights reserved.