Table 2.

Prion variants/strains

Prion	Variant discriminant	Ref.
TSE	Incubation period
	Region of brain affected
	Interspecies transmission efficiency
	Clinical signs: dementia, ataxia, glucose intolerance…
[PSI+]	Strong/Weak: efficiency of terminator read-thru	(Derkatch et al. 1996)
	Stability: directly related to seed number	(Derkatch et al. 1996)
	Lethal/Toxic/Mild	(McGlinchey et al. 2011)
	Pattern of sensitivity to intraspecies transmission barriers from polymorphic Sup35 prion domain	(Bateman and Wickner 2012; Bateman and Wickner 2013)
	Sensitivity to interspecies barriers	(Sharma et al. 2015)
	Ability to propagate in various mutant prion proteins	(King 2001)
	Sensitivity to chaperone over/under production	(Borchsenius et al. 2006) (Kushnirov et al. 2000) (Lancaster et al. 2013)(Harris et al. 2014)
[URE3]	Strong/Weak: level of DAL5 promoter activity	(Brachmann et al. 2005)
	Stability: directly related to seed number	(Brachmann et al. 2005)
	Toxic/Mild	(McGlinchey et al. 2011)
	Btn2-Cur1 Sensitive/Hypersensitive	(Wickner et al. 2014)
	Species barrier sensitive/resistant	(Edskes et al. 2009)
[PIN+]	Strong/weak: efficiency of generating [PSI+]	(Bradley et al. 2002)
	Pattern of [PSI+] variants generated	(Sharma and Liebman 2013)