Other CD Antigens

CD40 belongs to the TNF-receptor super family. CD40 has been found to be vital in mediating a wide range of immune and inflammatory responses including T cell-dependent immunoglobulin class switching, memory B cell development, and germinal center formation. AT-hook transcription factor AKNA is accounted to coordinately regulate the expression of CD40 and its ligand, which is significant for homotypic cell interactions. Adaptor protein TNFR2 interacts with CD40 and functions as a mediator of the signal transduction. The interaction of CD40 and its ligand is found to be essential for amyloid-beta-induced microglial activation, and therefore is considered to be an early event in Alzheimer disease pathogenesis.

CD96 is a type I membrane protein which is a part of the immunoglobulin superfamily. CD96 functions as cell markers in immune-phynotyping and participates in antigen presentation. CD96 plays a role in the adhesive interactions of activated T and NK cells through the late phase of the immune response.

Thy-1 membrane glycoprotein (CD90) is a cell membrane protein which contains one lg-like V-type (immunoglobulin-like) domain. CD90 protein belongs to the immunoglobulin superfamily of adhesion molecules with constitutive expression on fibroblast cells. CD90 protein is involved in cell adhesion and cell communication in numerous cell types, predominantly in cells of the immune and nervous systems. CD90 may also have a role in cell-cell or cell-ligand interactions during synaptogenesis and other events in the brain. CD90 can be used as a marker for various stem cells and for the axonal processes of mature neurons. CD90 may serve as a tumor suppressor in nasopharyngeal carcinoma.

CD9 which is found on the surface of exosomes is a cell surface glycoprotein which interacts with integrins and various transmembrane superfamily proteins. CD9 is involved in platelet activation and aggregation and also regulates paranodal junction formation. CD9 takes part in cell adhesion and migration and also promotes muscle cell fusion. CD9 is necessary for the egg-sperm fusion during mammalian fertilization.

CD9 which is found on the surface of exosomes is a cell surface glycoprotein which is interacts with integrins and various transmembrane superfamily proteins. CD9 is involved in platelet activation and aggregation and also regulates paranodal junction formation. CD9 takes part in cell adhesion and migration and also promotes muscle cell fusion. CD9 is necessary for the egg-sperm fusion during mammalian fertilization.

CD9 which is found on the surface of exosomes is a cell surface glycoprotein which is interacts with integrins and various transmembrane superfamily proteins. CD9 is involved in platelet activation and aggregation and also regulates paranodal junction formation. CD9 takes part in cell adhesion and migration and also promotes muscle cell fusion. CD9 is necessary for the egg-sperm fusion during mammalian fertilization.

CD8 protein is a glycoprotein that is located on the cell surface of cytotoxic T lymphocytes the interferes interactions between cells of the immune system. This protein is a coreceptor that helps detect antigens shown by the APC (antigen presenting cells) as part of the class I MHC proteins. It can be a homodimer build from 2 alpha chains orheterodimer build from alpha and beta chains.

CD86, also known as B7-2 or Cluster of Differentiation 86 is a protein necessary for T cell activation and survival, it is expressed on cells that are antigen-presenting cells and acts as costimulatory signals for T cells. CD86 is the ligand for CD28 (for autoregulation and intercellular association) and CTLA-4 (for attenuation of regulation and cellular disassociation), two different proteins.

CD83 is a single-pass type I membrane protein and part of the immunoglobulin superfamily of receptors. CD83 involves in the regulation of antigen presentation. A soluble form of CD83 can bind to dendritic cells and inhibit their maturation. There were 3 transcript variants encoding different isoforms for CD83.

CD81 antigen isoform 1, also known as CD81, is part of the tetraspanin family. CD81 interacts directly with immunoglobulin superfamily member 8 (IGSF8, CD316) and CD36. In B cells, CD81 is part of a complex with CD21, CD19 and Leu13. Furthermore, this complex decreases the threshold for B cell activation through B cell receptors by linking Ag specific recognition and CD21 mediator recognition. While on T cells CD81 connects with CD4 and CD8 and provides a costimulatory signal with CD3.

CD72 antigen is a member of the type II integral membrane glycoproteins which includes other related cell surface moleculaes such as the asialoglycoprotein receptors, CD23 and the Kupffer cell recpeotr. The exposure of B cells to CD72 antibodies activates a variety of signalling pathways and can induce MHC class II expression and B cell proliferation. CD72 antigen is expressed on all cells of B cell lineage with the exception of plasma cells and weakly on human tissue macrophages.

CD72 antigen is a member of the type II integral membrane glycoproteins which includes other related cell surface moleculaes such as the asialoglycoprotein receptors, CD23 and the Kupffer cell recpeotr. The function of CD72 is unknown but the exposure of B cells to CD72 antibodies activates a variety of signaling pathways and can induce MHC class II expression and B cell proliferation. CD72 antigen is expressed on all cells of B cell lineage with the exception of plasma cells and weakly on human tissue macrophages.

CD69 is a type 2 transmembrane glycoprotein which belongs to the C-type lectin family. CD69 is a very early activation Ag of T lymphocytes. The expression of CD69 is induced upon activation of T lymphocytes, and CD69 takes part in proliferation. Moreover, CD69 acts to transmit signals in natural killer cells as well as platelets. CD69 functions in the pathogenesis of allergen induced eosinophilic airway inflammation and responsiveness. Among the diseases which are associated with CD69: cd3gamma deficiency and mast cell disease.

CD6 is a cell surface glycoprotein expressed primarily on T cells. CD6 is expressed by mature T-cells, thymocytes, a subset of B-cells known as B-1 cells, and by cells in the brain (some of them). CD6 is a member of the group B SRCR (scavenger receptor cysteine-rich) superfamily. CD6 plays a role as both a co-stimulatory molecule in T cell activation and as an adhesion receptor. CD6 binds to CD166 and is considered as a costimulatory molecule involved in lymphocyte activation and thymocyte development.

CD59 is a cell surface glycoprotein which regulates complement-mediated cell lysis, and it is involved in lymphocyte signal transduction. CD59 is an effective inhibitor of the complement membrane attack complex, whereby it binds complement C8 and/or C9 during the compilation of this complex, thus inhibiting the incorporation of multiple copies of C9 into the complex, which is essential for osmolytic pore formation. In addition, CD59 has a role in signal transduction pathways in the activation of T cells. CD59 gene mutations cause CD59 deficiency, a disease resulting in hemolytic anemia and thrombosis, and which causes cerebral infarction.

CD57 also called B3GAT1is part of the glucuronyltransferase gene family. CD57 exhibits strict acceptor specificity, recognizing nonreducing terminal sugars and their anomeric linkages. CD57 takes part in the glucuronyl transfer reaction during the biosynthesis of the carbohydrate epitope HNK-1.

CD52 is a small GPI (glycosylphosphatidylinositol) anchored glycoprotein which is tied to the cell surface with a GPI linkage. CD52 induces immune suppression by complement-meditated cell lysis. Moreover, CD52 is expressed on lymphocytes, eosinophils, monocytes-derived dendritic cells, monocytes, as well as neutrophils, however not on the stem cells from which these lymphocytes were derived. Furthermore, CD52 is a significant goal for therapeutic interventions intended for leukocyte depletion in post-transplant immunosuppression & hematological malignancies.

CD48, is a GPI-linked protein which belongs to the CD2 family of immunoglobulin superfamily molecules. CD48 is capable to transduce signals and can likewise trigger signaling through CD2 or 2B4. CD48 to CD2 interactions advocate T cell activation and class replacing to IgG2a in B cells. In addition, high affinity of CD48 to 2B4, interactions may either promote or inhibit NK cell as well as cytotoxic T cell (CTL) activation. CD48 does not contain a transmembrane domain, though it is held at the cell surface by a GPI anchor through a C-terminal domain which possibly split to produce a soluble form of the receptor.

CD44 is a cell-surface glycoprotein that plays a role in cell-cell interactions, cell adhesion and migration. CD44 is a receptor for hyaluronic acid and also interacts with other ligands, such as osteopontin, collagens, and matrix metalloproteinases. CD44 participates in a wide variety of cellular functions such as lymphocyte activation, recirculation and homing, hematopoiesis, and tumor metastasis.

CD43 is a key sialoglycoprotein located in the surface of T lymphocytes, monocytes, granulocytes, thymocytes and some B lymphocytes. CD43 is a part of a physiologic ligand-receptor complex which participates in T-cell activation. Throughout T-cell activation, CD43 is actively taken out from the T-cell-APC (antigen-presenting cell) contact site, signifying CD43 has a negative regulatory role in adaptive immune response.

CD3D, also known as Delta Polypeptide (TiT3 Complex), is a single-pass type 1 membrane protein. CD3D jointly with CD3-zeta, CD3-gamma, CD3-epsilon and the T-cell receptor alpha/beta and gamma/delta heterodimers, creates the T-cell receptor-CD3 complex. Once antigen presenting cells (APCs) activate T-cell receptor (TCR), TCR-mediated signals are transferred through the cell membrane by the CD3 chains CD3D, CD3E, CD3G and CD3Z. Likewise, CD3D takes an important part in adaptive immune response and participates in thymocyte differentiation.

CD38 is a surface molecule which acts as a plasma membrane signaling receptor in leukocytes. Furthermore, CD38 functions as signaling channel which leads to to cellular activation and proliferation. CD38 also plays a role as an ectoenzyme with various functions as well as an inducer of Ca2+ mobilization from cytoplasmic stores. CD38 signals acts as a coreceptor on B cells and modulates B cell receptor.

CD37 belongs to the transmembrane 4 superfamily, otherwise known as the tetraspanin family. Most of its members are cell-surface proteins which are distinguished by the presence of 4 hydrophobic domains. These proteins mediate signal transduction events which have a role in the regulation of cell development, activation, growth and motility. CD37 protein is a cell surface glycoprotein which is known to form complexes with integrins and other transmembrane 4 superfamily proteins. CD37 may also havea role in T-cell-B-cell interactions.

Platelet glycoprotein IV, also known as CD36 is an integral membrane glycoprotein which has multiple physiological functions. CD36 is broadly expressed on a wide array of cell types. CD36 is part of the scavenger receptor family and acts as a multiligand pattern recognition receptor which interacts with a large number of structurally dissimilar ligands. Furthermore, CD36 participates in lipid metabolism and has been known as a fatty acid translocase which is required for the binding as well as transport of LCFA in cells & tissues. CD36 also takes a major part in the initiation as well as pathogenesis of chronic inflammatory diseases such as Alzheimer’s disease and atherosclerosis. CD36 is an integral membrane protein which mainly functions as a receptor for thrombospondin & collagen. CD36 directly mediates the cytoadherence of Plasmodium falciparum parasitized erythrocytes.

CD320 is a part of the low-density lipoprotein receptor family, having 2 low-density lipoprotein receptor type A domains divided by a complement-like cysteine-rich region. CD320 participates in cobalamin uptake and internalizes the complex by endocytosis. CD320 is also plays a role as costimulator to promote B cell and follicular dendritic cells responses. CD320 is also known to augment the proliferation of PC precursors generated by IL-10.

Tumor necrosis factor receptor superfamily member 8 (CD30) is a member of the TNF-receptor superfamily. CD30 is expressed by activated (not by resting) T and B cells. CD30 interacts with TRAF2 and TRAF5 which mediate the signal transduction that leads to the activation of NF-kappaB. CD30 is a positive regulator of apoptosis, and also has been shown to limit the proliferative potential of autoreactive CD8 effector T cells and protect the body against autoimmunity.

CD28 co-stimulation is necessary for CD4 positive T-cell proliferation & survival, interleukin-2 production, and T-helper type-2 development. Human post-thymic regulatory T cells require CD28 co-stimulation to expand and maintain potent suppressive function in vivo. Apoptosis plays a key role in the age-related decline of CD28 expression and in immunosenescence.

CD276, belongs to the B7 family of immunoregulatory transmembrane glycoproteins expressed by T cells. CD276 is a costimulatory molecule for T cell activation in addition to IFN-gamma production. Furthermore, CD276 upregulates BRCC3 expression, preventing DNA defects caused by 5-Fu. CD276 is correlated with TNM stage of NSCLC and act as a potential biomarker for NSCLC-derived MPEs. CD276 inhibits natural-killer mediated cell lysis in tumor cells, and act as a marker for detection of neuroblastoma cells. CD276 is implicated in the development of acute as well as chronic transplant rejection and in the regulation of lymphocytic activity at mucosal surfaces. In addition, CD276 provides the placenta & fetus a proper immunological environment during the course of pregnancy.

CD276, belongs to the B7 family of immunoregulatory transmembrane glycoproteins expressed by T cells. CD276 is a costimulatory molecule for T cell activation in addition to IFN-gamma production. Furthermore CD276 upregulates BRCC3 expression, preventing DNA defects caused by 5-Fu. CD276 is correlated with TNM stage of NSCLC and act as a potential biomarker for NSCLC-derived MPEs. CD276 inhibits natural-killer mediated cell lysis in tumor cells, and act as a marker for detection of neuroblastoma cells. CD276 is implicated in the development of acute as well as chronic transplant rejection and in the regulation of lymphocytic activity at mucosal surfaces. In addition, CD276 provides the placenta & fetus a proper immunological environment during the course of pregnancy.

CD22, also known as Sialic Acid-Binding Ig-Like Lectin 2, is part of the immunoglobulin(Ig)superfamily. CD22 mediates B-cell to B-cell interactions and is implicated in the localization of B-cells in lymphoid tissues. CD22 acts as positive regulator via interaction with the Src family tyrosine kinases, in addition CD22 preform as an inhibitory receptor by recruiting cytoplasmic phosphatases.

CD21 is expressed strongly on mature B cells, follicular dentritic cells and weakly on immature thymocytes and T lymphocytes. In B-cell ontogeny, CD21 appears after the pre-B-stage, is maintained during peripheral B-cell development and is lost upon terminal differentiation into plasma cells. CD21 expression is also gradually lost after stimulation of B cells in vitro. CD21 functions as receptor for C3d, C3dg and iC3b Complement components, for EBV and for IFNalpha. CD21 binds to CD23 and associates with CD19, CD81 and Leu13 to form a large signal-transduction complex involved in B cell activation.

CD209 (a member of the C-typelectin family) is Pathogen-recognition receptor expressed on the surface of immature dendritic cells (DCs) andtakes part in initiation of primary immune response.CD209has a high affinity for theICAM3 molecule and binds various microorganisms by recognizing high-mannose-containing glycoproteins ontheir envelopes and especially functions as receptor for several viruses such as HIV and Hepatitis C. Along with other C-typelectins, CD209is involved in recognition of tumors by dendritic cells.CD209also initiatesnatural immunity bymodulating toll-like receptors.

CD19, also known as B-Lymphocyte Surface Antigen B4, belongs to the Ig superfamily which is expressed on the surface of all B-lymphoid cells with the exception of terminally differentiated plasma cells. CD19 is involved as a signal-transducing receptor in the control of differentiation as well as proliferation. CD19 is as an adaptor protein which drafts cytoplasmic signaling proteins to the membrane and operates within the CD19/CD21 complex to decrease the threshold for B cell receptor signaling pathways. CD19 is present on all B cells, and therefore is a biomarker for lymphoma diagnosis, B lymphocyte development and can be used as a target for leukemia immunotherapies.

CD18 (ITGB2 or integrin beta-2) is a receptor for ICAM1, ICAM2, ICAM3 and ICAM4. CD18 may be a member of an extended family of cell surface molecules including the fibronectin binding protein. In addition, CD18 is a complement receptor type 3 (CR3). CD18 triggers neutrophil transmigration during lung injury through PTK2B/PYK2-mediated activation.

CD164 Sialomucin-Like 2, also known as CD164L2 is amember of the CD164 family.

CD163 is an acute phase-regulated receptor which participates in the removal and endocytosis of hemoglobin/haptoglobin complexes by macrophages and thus keeps tissues from free hemoglobin-mediated oxidative damage. Furthermore, CD163 partakes in the uptake and recycling of iron, through endocytosis of hemoglobin/haptoglobin and ensuing breakdown of heme. In addition, CD163 binds hemoglobin/haptoglobin complexes in a calcium-dependent and pH-dependent way. CD163 demonstrates greater affinity for complexes of hemoglobin and multimeric haptoglobin of HP-1F phenotype than for complexes of hemoglobin and dimeric haptoglobin of HP-1S phenotype. Moreover, CD163 stimulates a cascade of intracellular signals which involves tyrosine kinase-dependent calcium recruitment, inositol triphosphate formation and secretion of IL-6 & CSF-1.

CD163 is an acute phase-regulated receptor which participates in the removal and endocytosis of hemoglobin/haptoglobin complexes by macrophages and thus keeps tissues from free hemoglobin-mediated oxidative damage. Furthermore, CD163 partakes in the uptake and recycling of iron, through endocytosis of hemoglobin/haptoglobin and ensuing breakdown of heme. In addition, CD163 binds hemoglobin/haptoglobin complexes in a calcium-dependent and pH-dependent way. CD163 demonstrates greater affinity for complexes of hemoglobin and multimeric haptoglobin of HP-1F phenotype than for complexes of hemoglobin and dimeric haptoglobin of HP-1S phenotype. Moreover, CD163 stimulates a cascade of intracellular signals which involves tyrosine kinase-dependent calcium recruitment, inositol triphosphate formation and secretion of IL-6 & CSF-1.

CD160 antigen (CD160) is a human natural killer (NK)-cell-activating receptor which is also expressed on T-cell subsets. CD160 is a tumor-specific antigen known to mediate cellular activation signals in CLL, and is a novel target for therapeutic manipulation and monitoring of minimal residual disease. CD160 was identified as a T cell coinhibitory molecule which interacts with the herpesvirus entry mediator (HVEM) on antigen-presenting cells to deliver a potent inhibitory signal to CD4(+) T cells. CD160 expression is strongly associated with peripheral blood NK cells and CD8 T lymphocytes with cytolytic effector activity. CD160 is expressed on all intestinal intraepithelial lymphocytes. CD160 has a broad specificity for binding to both classical and nonclassical MHC class I molecules.

Semaphorin-4D (CD100) is a member of the semaphorin family containing 1 Ig-like C2-type domain, 1 PSI domain and 1 Sema domain. CD100 is the cell surface receptor forPLXN1B and PLXNB2 which plays a central role in cell-cell signaling. CD100 stimulates the migration of cerebellar granule cells and of endothelial cells, regulates dendrite and axon branching and morphogenesis. In addition, CD100 has a role in the immune system; it promotes signaling via SRC and PTK2B/PYK2, which subsequently mediates activation of phosphatidylinositol 3-kinase and of the AKT1 signaling cascade.

Basigin Isoform 2 or BSG is a part of the immunoglobulin superfamily, it is a type 1 transmembrane protein which has a variety of Nand O- glycosylation. BSG has several ligands, such as integrins, cyclophilin proteins Cyp-A & CyP-B. The protein has a crucial role in intercellular recognition, it takes part in many immunologic processes, differentiation and cell development. Also, it regulates numerus cell processes such as production and release of expression of the mono-carboxylate transporter, spermatogenesis, etc. Basigin Isoform 2 promotes invasion, metastasis, growth and survival of malignant cells by producing and releasing matrix metalloproteinases nearby mesenchymal cells and tumor cells.

Ectonucleoside Triphosphate Diphosphohydrolase 6 or ENTPD6 is an enzyme, akin to E-type nucleotidases. E-type nucleotidases, for instance CD39, are responsible for extracellular nucleotides catabolism. ENTPD6 has four apyrase-conserved areas like all to E-type nucleotidases. Rather spliced transcript agents that codes various isoforms were discovered for the DNA segment.

Ectonucleoside Triphosphate Diphosphohydrolase 6 or ENTPD6 is an enzyme, akin to E-type nucleotidases. E-type nucleotidases, for instance CD39, are responsible for extracellular nucleotides catabolism. ENTPD6 has four apyrase-conserved areas like all to E-type nucleotidases. Rather spliced transcript agents that codes various isoforms were discovered for the DNA segment.

Basal Cell Adhesion Molecule (BCAM) which is a product of alternate splicing of the Lutheran blood group molecule is a part of the immunoglobulin superfamily. BCAM contains five extracellular immunoglobulin domains, a single transmembrane domain, and a short C-terminal cytoplasmic tail. BCAM protein is upregulated following malignant transformation of some cell types in vivo and in vitro. Furthermore, BCAM interacts with integrin in sickle red cells, and participates in vasoocclusive episodes.

CD166 antigen isoform 2 (ALCAM) is a type 1 membrane glycoprotein and belongs to the immunoglobulin superfamily. ALCAM is expressed on thymic epithelium, microvascular endothelium, activated lymphocytes and monocytes, and monocyte-derived dendritic cells. CD166 and CD6 interaction plays a role in T cell development and T cell regulation, as well as in the binding of T cells and B cells to activated leukocytes.

CD166 antigen isoform 2 (ALCAM) is a type 1 membrane glycoprotein and belongs to the immunoglobulin superfamily. ALCAM is expressed on thymic epithelium, microvascular endothelium, activated lymphocytes and monocytes, and monocyte-derived dendritic cells. CD166 and CD6 interaction plays a role in T cell development and T cell regulation, as well as in the binding of T cells and B cells to activated leukocytes.

MS4A1 is an activated-glycosylated phosphoprotein expressed on the surface of all B-cells. The expression begins at the pro-B phase and until maturity the concentration increases in order to allow optimal B-cell immune response, specifically against T-independent antigens. MS4A1 takes part in the microenvironmental interactions of B cells and also in the regulation of B-cell activation and proliferation. MS4A1 also plays a role as a calcium channel in the cell membrane.

Cytotoxic and Regulatory T Cell Molecule, also known as CRTAM belongs to the immunoglobulin superfamily which complies with the structural characteristics of the JAM family and is phylogenetically more closely related to nectin-like proteins. CRTAM is implicated in epithelial cell adhesion. Furthermore, CRTAM interacts with CADM1 as well as promotes natural killer (NK) cell cytotoxicity.