The NKp46 protein was named as such since a 46-kDa band was precipitated from NK cells, using NKp46-specific mAb. Molecular cloning of the NKp46 cDNA revealed that NKp46 is a member of the immunoglobulin superfamily, characterized by two extracellular C2-type Ig-like domains.Although it has been recently demonstrated that NKp46 is expressed on a special subset of lymphocytes of the innate immune system, NKp46 is still considered a unique NK cell marker and is the only NCR that has a mouse ortholog, named NCR1.