CD45 (PTPRC) - General marker for hematopoietic and immune cells.

CD-markers (Cluster of Differentiation) are antibodies that recognize cell surface antigens and antibodies detecting specific CD antigens are used in immunohistochemistry, mainly to distinguish different types of immune cells. The PTPRC gene encodes for the CD45 molecule (leucocyte common antigen, LCA), a receptor type protein tyrosine phosphatase. CD45 functions as an essential regulator of T- and B-cell antigen receptor signaling. CD45 is exclusively expressed in cells from the hematopoietic and immune systems. Almost all hematopoietic and lymphoid cells, including precursor cells and mature B- and T-lymphocytes, granulocytes, monocytes/histiocytes and interdigitating reticulum cells and follicular dendritic cells express CD45. CD45 is lost in maturing erythocytes, megakaryocytes and plasma cells. CD45 antibodies are used as a general marker for hematopoietic and lymphoid cells in diagnostics of lymphoma/leukemia and to determine inflammatory cell infiltrates.