The following is a list of human clusters of differentiation (or CD) molecules.
* = group; ** = not listed on hcdm
CD1* MHC-like molecule that presents lipid moleculesCD1aCD1a (Cluster of Differentiation 1a), or T-cell surface glycoprotein CD1a, is a human protein encoded by the CD1A gene. An antigen-presenting protein that binds self and non-self lipid and glycolipid antigens and presents them to T-cell receptors on natural killer T-cells. CD1bT-cell surface glycoprotein CD1b. Expressed on cortical thymocytes, certain T-cell leukemias and other tissues.CD1cT-cell surface glycoprotein CD1c.CD1dT-cell surface glycoprotein CD1d encoded by the CD1D gene. CD1d-presented lipid antigens activate a special class of T cells, known as natural killer T (NKT) cells, through the interaction with the T-cell receptor present on NKT membranesCD1eT-cell surface glycoprotein CD1e is a protein in humans encoded by the CD1E gene. CD2 a type I transmembrane protein found on thymocytes, T cells, and some natural killer cells that acts as a ligand for CD58 and CD59 and is involved in signal transduction and cell adhesion; expressed in T-cell acute lymphoblastic leukemia and T-cell lymphoma. CD3* the signaling component of the T cell receptor (TCR) complexCD3dT-cell surface glycoprotein CD3 delta chainCD3eT-cell surface glycoprotein CD3 epsilon chainCD3gT-cell surface glycoprotein CD3 gamma chain CD4 a co-receptor for MHC Class II (with TCR, T-cell receptor); found on the surface of immune cells such as T helper cells, monocytes, macrophages, and dendritic cells. Used by HIV to enter T cells: in HIV infection. CD8+ cytotoxic T cells recognize and kill infected cells hence they are predominantly for protection against intracellular pathogens, e.g. viruses, and some bacteria, i.e. Rickettsiae CD5 a type I transmembrane protein found on T cells, thymocytes, and some B cells that is a ligand for CD72 and is involved in cellular activation or adhesion; expressed in B-cell chronic lymphocytic leukemia and T-cell lymphoma. CD6 adhesion molecule linking developing thymus-cells to thymus epithelial cells; co-stimulator to mature T cells; binds CD166 CD7 a type I transmembrane protein found on thymocytes, some T cells, monocytes, natural killer cells, and hematopoietic stem cells; expressed in patients with mycosis fungoides, some patients with T-cell acute lymphoblastic leukemia, and a few patients with acute nonlymphocytic leukemia CD8* a co-receptor (with TCR, T-cell receptor) for MHC Class I; mostly found on cytotoxic T cells, but also on natural killer cells, cortical thymocytes, and a subset of myeloid dendritic cells. In HIV infection, CD8+ cytotoxic T cells recognise and kill infected CD4+ helper T cells, which are critical for the body's immunity. In HBV infection CD8+ cytotoxic T cells are involved in liver injury by killing infected cells and by producing antiviral cytokines capable of purging HBV from viable hepatocytes. There are two isoforms of the protein, alpha and beta, each encoded by a different gene (below).CD8aT-cell surface glycoprotein CD8 alpha chain. Identifies cytotoxic/suppressor T-cells that interact with MHC class I bearing targetsCD8bT-cell surface glycoprotein CD8 beta chain. CD9 a member of the Tetraspanin superfamily expressed in a variety of cells, including: pre B cells, eosinophils, basophils and platelets. CD10 a type II transmembrane protein found on pre-B cells, germinal-center B cells, some neutrophils, kidney cells, T-cell precursors, and epithelial cells that acts as a zinc metalloprotease cleaving peptide bonds on the amino side of hydrophobic amino acids; expressed in acute lymphocytic leukemia and follicular-center-cell lymphomas. CD11a Integrin Alpha L (ITGAL), the alpha subunit of LFA-1, a membrane glycoprotein that provides cell-cell adhesion by interaction with ICAM-1 CD11b Integrin Alpha M (ITGAM); the alpha subunit of Mac-1 (Macrophage-1 antigen), the CR3 complement receptor which consists of CD11b and CD18. CR3 is a human cell surface receptor, found on polymorphonuclear leukocytes (mostly neutrophils), NK cells, and mononuclear phagocytes like macrophages, which is capable of recognizing and binding to many molecules found on the surfaces of invading bacteria. Binding to the receptor causes phagocytosis and destruction of the foreign cell. CD11c Integrin Alpha X (ITGAX), the alpha subunit of (iC3b) receptor 4 (CR4). It is a type I transmembrane protein found on monocytes, macrophages, neutrophils, and some B cells that induces cellular activation and helps trigger neutrophil respiratory burst; expressed in hairy cell leukemias, acute nonlymphocytic leukemias, and some B-cell chronic lymphocytic leukemias. Also one of the defining markers for dendritic cells and hairy cell leukemia cells.CD11dIntegrin alpha-D - ITGAD. Integrin alpha-D/beta-2 is a receptor for ICAM3 and VCAM1. May play a role in the atherosclerotic process such as clearing lipoproteins from plaques and in phagocytosis of blood-borne pathogens, particulate matter, and senescent erythrocytes from the blood. CD13 a zinc metalloproteinase, also known as aminopeptidase N, which is found naturally on myelomonocytic cells from early differentiation through maturity; usually present on acute myeloid leukemia blasts and rarely found in some forms of lymphoma and lymphocytic leukemia CD14 a membrane protein found on macrophages which binds to bacterial lipopolysaccharide. CD15 a carbohydrate adhesion molecule (not a protein) that mediates phagocytosis and chemotaxis, found on neutrophils; expressed in patients with Hodgkin disease, some B-cell chronic lymphocytic leukemias, acute lymphoblastic leukemias, and most acute nonlymphocytic leukemias. It is also called Lewis x and SSEA-1 (stage specific embryonic antigen 1) and represents a marker for murine pluripotent stem cells, in which it plays an important role in adhesion and migration of the cells in the preimplantation embryo.CD16* FcγRIII, a low-affinity Fc receptor for IgG. Found on NK cells, macrophages, and neutrophils.CD16aLow affinity immunoglobulin gamma Fc region receptor III-A encoded by the FCGR3A gene. Mutations in the gene associated with immunodeficiency, particularly severe Epstein Barr virus and HPV infections.CD16bLow affinity immunoglobulin gamma Fc region receptor III-B encoded by the FCGR3B gene. Expressed by neutrophils and stimulated eosinophils CD17 possible role in phagocytosis. Bacteria binding. CD18 Integrin Beta 2 chain (ITGB2). Adhesion and signaling in the hematopoietic system.CD19 B-lymphocyte surface antigen B4, component of the B-cell co-receptor; highly represented in B-cell malignancies, CD19 is the target of several CAR-T and mAb cancer drugs in development e.g. Juno JCAR015, Kite KTE-C19 CAR, Novartis CTL019, Morphosys MOR208, Macrogenics MGD011, Affimed AFM11 CD20 a type III transmembrane protein found on B cells that forms a calcium channel in the cell membrane allowing for the influx of calcium required for cell activation; expressed in B-cell lymphomas, hairy cell leukemia, and B-cell chronic lymphocytic leukemia. Important for therapy of those diseases, as antibodies against CD20 exist: e.g. Rituximab and Ofatumumab, with several more in development. Similarly, anti-CD20 monoclonal antibody Ocrelizumab is in trials for multiple sclerosis. CD21 CR2, a type I transmembrane protein found in the cytoplasm of pre-B cells and on the surface of mature B cells, follicular dendritic cells, pharyngeal and cervical epithelial cells, some thymocytes, and some T cells that plays a role in signal transduction; expressed in hairy cell leukemia, B-cell lymphoma, and some T-cell acute lymphocytic leukemias. Receptor for complement (C3d) and Epstein–Barr virus (EBV). CD22 a sugar binding transmembrane protein that specifically binds sialic acid with an immunoglobulin (Ig) domain located at its N-terminus. It is a member of the immunoglobulin superfamily and the SIGLEC family. CD22 functions as an inhibitory receptor for B cell receptor (BCR) signalling. Like CD19, CD22 is a cell surface marker for lymphocytes that is present on most B cell malignancies, including acute lymphoblastic leukemia and various subtypes of non-Hodgkin lymphoma, including diffuse large B-cell lymphoma. CD22 expression has been shown to be maintained in acute lymphoblastic leukemia that has lost CD19, making anti-CD22 a potential combination or follow on therapy for anti-CD19 therapy. Anti-CD22 monoclonal antibodies have been developed, notably inotuzumab ozogamicin, approved by the FDA in 2017 for relapsed and refractory CD22-positive B-ALL. Currently Juno Therapeutics has an anti-CD22 CAR-T in development. CD23 a type II transmembrane protein found on mature B cells, monocytes, activated macrophages, eosinophils, platelets, and dendritic cells that enhances capture and processing of antigen complexed with IgE. CD24 a glycoprotein expressed at the surface of most B lymphocytes and differentiating neuroblasts. This gene encodes a sialoglycoprotein that is expressed on mature granulocytes and in many B cells. The encoded protein is anchored via a glycosyl phosphatidylinositol (GPI) link to the cell surface. Is also known as Heat Stable Antigen (HSA). CD25 a type I transmembrane protein present on activated T cells, activated B cells, some thymocytes, myeloid precursors, and oligodendrocytes that associates with CD122 to form a heterodimer that can act as a high-affinity receptor for IL-2; expressed in most B-cell neoplasms, some acute nonlymphocytic leukemias, and neuroblastomas. CD26 Membrane-bound protease. T-cell costimulatory molecule. Cell adhesion molecule CD27 TNF-receptor (Tumor necrosis factor receptor superfamily member 7). Present on the surface of resting memory B cells. Binds to ligand CD70. Celldex has an agonist anti-CD27 mAb, CDX-1127, in early stage trials, which activates T-cells by substituting for CD70 and may have anti-tumour effects. Human B and T cell lymphomas often express CD27 at high levels. CD28 costimulatory receptor present on all T-cells. It functions by binding one of two possible costimulatory ligands, CD80 (B7.1) or CD86 (B7.2), thus eliciting a costimulatory effect on the T-cell CD29 AKA integrin beta-1 - a cell adhesion molecule. CD30 a type I transmembrane protein present on activated T and B cells that may play a role in cell activation and/or differentiation; expressed in Hodgkin disease, some T-cell lymphomas, and anaplastic large cell lymphomas. CD31 PECAM-1, a cell adhesion molecule on platelets and endothelial cells CD32A** FcγRII-a, a receptor for the Fc (constant) region of immunoglobulin G (IgG). Of the related pair FCGR2A and FCGR2B (CD32B), the 'A' type is considered the activating isoform. CD32B** FcγRII-b, a receptor for the Fc (constant) region of immunoglobulin G (IgG). Of the related pair FCGR2A (CD32A) and FCGR2B, the 'B' type is considered the inhibitory isoform. Ligation of CD32B on B cells downregulates antibody production and may, in some circumstances, promote apoptosis. Co-ligation of CD32B on dendritic cells inhibits maturation and blocks cell activation. CD33 a marker of unknown function found on immature myeloid cells, including acute myeloid leukemia blasts and mature monocytes. Anti-CD33 monoclonal antibodies are extensively used for the diagnosis of all types of AMLs. CD34 stem cell marker, adhesion, found on hematopoietic precursors (found in high concentrations in umbilical cord blood), capillary endothelium, and embryonic fibroblasts CD35 Complement receptor 1 (C3b/C4b receptor) CD36 Platelet glycoprotein IV or IIIb (GP IV / GP IIIb) CD37 A leucocyte restricted tetraspanin expressed primarily in B cells, but also found on T cells, Monocytes and Granulocytes. CD38 involved in ecto-ADP-ribosyl cyclase and cell activation on many hematopoietic, plasma, and B & T activated cells; marker increases with HIV seroconversion, coexpression with CD8 associated with progression (indicates