CD Markers

Synonyms

CD molecules; Cluster of differentiation; Human leukocyte differentiation antigens

Definition

CD markers are leukocyte cell surface molecules, as well as the respective ligands expressed by other tissues. CD markers are used to identify, count, study, purify, destroy, or in some other way work with leukocytes. The name originated from studies using antibodies against leukocytes, and the term CD marker is used in the context of antibody-based studies, although the CD number refers to the leukocyte molecule, not to the antibody used to detect it.

The CD nomenclature was devised to achieve standardization at a time when many new monoclonal antibodies were being described against leukocyte antigens. The number of published antibodies was increasing rapidly, and in many cases the corresponding antigens were unknown, and it was difficult to establish whether two antibodies with similar reactivities were in fact against the same antigen or not. The first International Workshop and...