Description: This A1 monoclonal antibody reacts with Ly49A, a 44-kDa member of the Ly49 family of type II transmembrane receptors expressed on natural killer (NK) cells. This receptor is present as a disulfide-linked homodimer with C-type lectin extracellular domains. An inhibitory receptor, Ly49A binds MHC class I molecules, such as H-2Dd, H-2Dk, and H-2DP, to inhibit NK-mediated cytotoxicity by triggering phosphorylation of its ITIM domain and recruitment of SHP-1 and SHP-2. Ly49A is expressed on DX5+CD3- NK cells and DX5+CD3+ NK T cells, as well as on a population of memory CD8+ T cells in C57BL/6, C57BL/10, and B10 congenic mice.