The myeloid-associated immunoglobulin-like receptor family (CD300) consists of nine activating or inhibitory cell surface receptors preferentially expressed on myloid cells and are encoded by the genes in a small cluster on mouse chromosome 11. MAIR-V is one of the family members. MAIR-V regulates the activation of myeloid cells. It has been reported that cross-linking MAIR-V with anti-MAIR-V monoclonal antibody induced cell death in peritoneal macrophages as well as transfectants. Data suggested that MAIR-V is one of the inhibitory receptors in the family. The functional of characteristics of this receptor are still not clear. Monoclonal antibody TX70 recognized both MAIR-Va and MAIR-Vb.