ERAP1 and infection: In addition to using a non-classical MHC class Ib-restricting molecule, QFL T cells have other characteristics of unconventional T cells, including the predominant use of a fixed TCR α chain and an antigen-experienced (CD44+) phenotype in naive mice.29,30 It has been suggested that QFL T cells may monitor cells for ERAAP dysfunction,28 but whether QFL T cells play a role during infection remains unknown.