Cluster of differentiation antigen (CD antigen (for specific molecules, e.g., CD4, CD8, etc.))

Differentiation antigens (most commonly referred to as Cluster of Differentiation or CD antigens) are molecules present on the membranes of living cells, whose expression reflects distinct stages of cell maturation and differentiation, particularly within the immune system. These antigens serve as important cell markers for immunophenotyping, play essential roles in cell signaling, cell adhesion, and immune response, and are frequently used as diagnostic and therapeutic targets in diseases such as cancer and autoimmune disorders. Individual CD antigens are associated with particular cell types (e.g., CD4 on helper T cells, CD8 on cytotoxic T cells) and their identification is fundamentally important for clinical and research immunology.

Other names

Cluster of differentiationCD antigenT-cell differentiation antigenclassification determinantcluster of designation

Drug mechanisms include antibody-dependent cell-mediated cytotoxicity, complement-dependent cytotoxicity, and immune modulation—mechanisms are specific to each CD target.