CD123

This antibody reacts with the CD123 antigen, the α chain of the IL-3 receptor. This 60-70 kDa transmembrane protein binds to IL-3 with low affinity by itself, and when associated with CD131 (common β chain) binds IL-3 with high affinity. CD123 is expressed by myeloid precursors, macrophages, dendritic cells, mast cells, basophils, and megakaryocytes. At the level of the hematopoietic system IL-3R alpha expression was described on bone marrow CD34+ cells (including primitive multipotential and committed progenitors), granulocytes, monocytes/macrophages, megakaryocytes and B-lymphocytes. Although the IL-3R alpha is expressed on the large majority of progenitor cells, it does not seem to be expressed on the stem cell fraction.