CD3 protein complex (T cell co-receptor) (CD3)

CD3 is a multimeric protein complex expressed on the surface of all mature T lymphocytes. It forms a critical part of the T cell receptor (TCR)/CD3 complex that mediates antigen recognition and signal transduction, triggering T cell activation and immune responses[2][3][5]. "Mature CD3-positive lymphocyte" refers to T cells which have completed maturation in the thymus and are capable of participating in adaptive immunity. CD3 expression defines the T cell lineage and is used as a diagnostic and prognostic marker in hematology and oncology. Therapeutically, CD3 is targeted by immunosuppressive and immunomodulatory antibodies in transplantation and autoimmune disease, and by T cell-engaging antibodies in cancer. The term "mature CD3-positive lymphocyte" is commonly used in immunophenotyping to identify and monitor T cells but is not the canonical name of a molecular target. The correct target is the CD3 protein complex itself[2][3][4].

Other names

T lymphocyte, matureCD3+ T lymphocyteMature T cellCD3+ lymphocyte

Antibody-mediated modulation or depletion of T cells (immunosuppression); T cell activation or redirection (e.g., bispecific T cell engager therapy)