Cluster of differentiation protein (CD) (CD)

The Cluster of Differentiation (CD) protein designation is a standardized nomenclature system used to identify cell surface molecules on leukocytes and other cell types (HCDM, 2023). This system was established to simplify the naming of cell surface antigens recognized by monoclonal antibodies, with over 370 CD numbers currently assigned (Zola et al., 2007; NCBI Gene). CD proteins encompass a diverse range of molecular classes, including receptors, adhesion molecules, and enzymes, which are essential for immune response, cell signaling, and cell-cell interactions (UniProt). Because the term "CD protein" refers to a broad classification rather than a single molecule, it is considered a generic category rather than a specific therapeutic target. However, individual members of this group, such as CD19, CD20, and CD38, are critical targets for monoclonal antibodies and CAR-T cell therapies in the treatment of hematologic malignancies and autoimmune diseases (PubMed, 2022). The biological functions and clinical significance of these proteins vary widely depending on the specific CD molecule and the cell type on which it is expressed.

Other names

CD markerCluster of differentiationCell surface antigenLeukocyte antigen

The mechanism of action depends entirely on the specific CD protein being targeted; common mechanisms for CD-targeted therapies include antibody-dependent cellular cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC), induction of apoptosis, and blockade of checkpoint signaling (StatPearls, 2023).