CD172a, also known as signal-regulatory protein α (SIRPα), is a 75–110 kDa transmembrane glycoprotein in the immunoglobulin superfamily. It consists of three Ig-like extracellular domains and two cytoplasmic immunoreceptor tyrosine-based inhibitory motifs (ITIMs). The interaction of ITIMs with the Src homology 2 domain-containing phosphatases SHP-1 and SHP-2 produces negative signaling in the regulation of leukocyte adhesion and transmigration, T cell activation, macrophage fusion, and phagocytosis. CD172a is expressed on monocytes/macrophages, granulocytes, dendritic cells, and neurons, but not on T and B lymphocytes. Clone SE5A5 recognizes a common epitope on CD172a and CD172b (SIRPβ) but is only weakly cross reactive with CD172b.
Anti-Human CD172a (SE5A5)-175Lu—100 Tests