Prions true is:

Prions are infectious particles, which can transmit disease. These prions are composed of chiefly a protein without any detectable nucleic acid. This is a new name widely accepted for the old name slow viruses. The term prion was coined by Prusiner for proteinaceous infectious particles.  Unlike conventional viruses, the prions apparently have no virion structure or genomes and evoke no immune response in the infected host. These are extremely resistant to inactivation by heat, disinfectants, and radiation. The prions are causative agents of slow viral infections, such as subacute spongiform encephalopathy. After long incubation period of years, they produce a progressive disease that causes damage to the central nervous system, leading to subacute spongiform encephalopathy.  They are readily inactivated by autoclave at 121oC and resistant to antiseptics and disinfectants. Parija SC. Textbook of Microbiology & Immunology. Elsevier Health Sciences; 2014. Page:438-39