What is "hla-e"

HLA class I histocompatibility antigen, alpha chain E (HLA-E) also known as MHC class I antigen E is a protein that in humans is encoded by the HLA-E gene. The human HLA-E is a non-classical MHC class I molecule that is characterized by a limited polymorphism and a lower cell surface expression than its classical paralogues. The functional homolog in mice is called Qa-1b, officially known as H2-T23.