Leukosialin also known as sialophorin or CD43 (cluster of differentiation
Cluster of differentiation
The cluster of differentiation is a protocol used for the identification and investigation of cell surface molecules present on white blood cells, providing targets for immunophenotyping of cells...

 43) is a transmembrane cell surface protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 that in humans is encoded by the SPN (sialophorin) gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...



Sialophorin (leukosialin) is a major sialoglycoprotein on the surface of human T lymphocytes, monocyte
Monocytes are a type of white blood cell and are part of the innate immune system of vertebrates including all mammals , birds, reptiles, and fish. Monocytes play multiple roles in immune function...

s, granulocyte
Granulocytes are a category of white blood cells characterized by the presence of granules in their cytoplasm. They are also called polymorphonuclear leukocytes because of the varying shapes of the nucleus, which is usually lobed into three segments...

s, and some B lymphocytes, which appears to be important for immune function and may be part of a physiologic ligand-receptor complex involved in T-cell activation.

Clinical significance

Defects in the CD43 molecule are associated with the development of Wiskott-Aldrich syndrome
Wiskott-Aldrich syndrome
Wiskott–Aldrich syndrome is a rare X-linked recessive disease characterized by eczema, thrombocytopenia , immune deficiency, and bloody diarrhea . It is also sometimes called the eczema-thrombocytopenia-immunodeficiency syndrome in keeping with Aldrich's original description in 1954...

. It also appears in about 25% of intestinal MALTomas. Using immunohistochemistry
Immunohistochemistry or IHC refers to the process of detecting antigens in cells of a tissue section by exploiting the principle of antibodies binding specifically to antigens in biological tissues. IHC takes its name from the roots "immuno," in reference to antibodies used in the procedure, and...

, CD43 can be demonstrated in the paracortical T-cells of healthy lymph nodes and tonsils; it is also positive in a range of lymphoid and myeloid tumours. Although it is present in over 90% of T-cell lymphoma
Lymphoma is a cancer in the lymphatic cells of the immune system. Typically, lymphomas present as a solid tumor of lymphoid cells. Treatment might involve chemotherapy and in some cases radiotherapy and/or bone marrow transplantation, and can be curable depending on the histology, type, and stage...

s, it is generally less effective at demonstrating this condition than is CD3 antigen. However, it may be useful as part of a panel to demonstrate B-cell lymphoblastic lymphoma
Lymphoblastic lymphoma
Lymphoblastic lymphoma is a rare type of non-Hodgkin lymphoma, a result of abnormal adaptive immune cells, typically T-cells. It usually occurs in children....

, since the malignant cells in this condition are often CD43 positive, and may be difficult to stain with other antibodies. Because it stains granulocytes and their precursors, it is also an effective marker for myeloid
A myelocyte is a young cell of the granulocytic series, occurring normally in bone marrow, but not in circulating blood .-Histology:...



CD43 has been shown to interact
Protein-protein interaction
Protein–protein interactions occur when two or more proteins bind together, often to carry out their biological function. Many of the most important molecular processes in the cell such as DNA replication are carried out by large molecular machines that are built from a large number of protein...

 with EZR and Moesin
Moesin is a protein that in humans is encoded by the MSN gene.Moesin is a member of the ERM protein family which includes ezrin and radixin. ERM proteins appear to function as cross-linkers between plasma membranes and actin-based cytoskeletons...


External links

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