CD159a, also known as NKG2A or KLRC1 (killer cell lectin-like receptor subfamily C, member 1), is a 43 kD type II transmembrane protein with extracellular C-type lectin domains. It belongs to the killer cell lectin-like receptor family also known as the NKG2 family. It is expressed on NK and NKT cells and activated CD8+ T cells. NKG2A binds to non-classical MHC class I molecule Qa-1 and causes inhibition of NK cell-mediated target-cell lysis.