CD markers are leukocyte cell surface molecules useful for identifying white blood cells and important for the diagnosis of leukemia and lymphocytes.
CD, abbreviation of ‘cluster of differentiation’ or ‘cluster designation’, is a protocol for identification and investigation of cell surface molecules. The nomenclature CD markers were developed in 1982 at First International Workshop and Conference on the Human Leukocyte Differentiation Antigens and since then the list of CD markers has been maintained.
CD markers are characterized by numbers. For instance, CD3 represents a CD marker on the surface of all mature T-cells which are a subset of white blood cells and play an important role in the body’s immune system. CD4 represents helper cells found on certain immune cells like T-cells, macrophages, and monocytes. CD4 activates the body’s response to infection. Likewise, CD8 is on cytotoxic T-cells and produces antibodies that help to fight viruses and other foreign invaders. There are more than 370 cell surface antigens of leukocytes referred as CD antigens that virtually tag each cell of the body by providing a unique identification number.
CD antigens can be used to monitor infection and detect neoplasm. Neoplasm is the abnormal growth of tissue caused by the rapid division of cells that have gone through mutation. Neoplasm may be precancerous, cancerous and non-cancerous and like other cells have CD markers that scientists can use to identify them. CD markers may help in identifying the effective treatment of cancer as well by monitoring changes in the relevant CD markers.
Moreover, researchers have created a type of protein called monoclonal antibody (mAb), which is a defensive protein and can be matched to a specific CD antigen. mAbs can be used to fight cancer by targeted immunotherapy treatment. Currently, 12 therapeutic monoclonal antibodies (TMA) are approved for cancer therapy, out of which five are employed for leukemia and lymphoma therapy. For example, in 1997, Rituxin was approved for the treatment of Non-Hodgkin B-cell lymphoma. It was the first TMA to be approved for cancer therapy.