Antigens cd81. Medical search

Substances that are recognized by the immune system and induce an immune reaction.

Differentiation antigens residing on mammalian leukocytes. CD stands for cluster of differentiation, which refers to groups of monoclonal antibodies that show similar reactivity with certain subpopulations of antigens of a particular lineage or differentiation stage. The subpopulations of antigens are also known by the same CD designation.

Differentiation antigens found on thymocytes and on cytotoxic and suppressor T-lymphocytes. CD8 antigens are members of the immunoglobulin supergene family and are associative recognition elements in MHC (Major Histocompatibility Complex) Class I-restricted interactions.

Proteins, glycoprotein, or lipoprotein moieties on surfaces of tumor cells that are usually identified by monoclonal antibodies. Many of these are of either embryonic or viral origin.

Complex of at least five membrane-bound polypeptides in mature T-lymphocytes that are non-covalently associated with one another and with the T-cell receptor (RECEPTORS, ANTIGEN, T-CELL). The CD3 complex includes the gamma, delta, epsilon, zeta, and eta chains (subunits). When antigen binds to the T-cell receptor, the CD3 complex transduces the activating signals to the cytoplasm of the T-cell. The CD3 gamma and delta chains (subunits) are separate from and not related to the gamma/delta chains of the T-cell receptor (RECEPTORS, ANTIGEN, T-CELL, GAMMA-DELTA).

Antigens on surfaces of cells, including infectious or foreign cells or viruses. They are usually protein-containing groups on cell membranes or walls and may be isolated.

Substances elaborated by bacteria that have antigenic activity.

A bifunctional enzyme that catalyzes the synthesis and HYDROLYSIS of CYCLIC ADP-RIBOSE (cADPR) from NAD+ to ADP-RIBOSE. It is a cell surface molecule which is predominantly expressed on LYMPHOID CELLS and MYELOID CELLS.

Glycoproteins found on immature hematopoietic cells and endothelial cells. They are the only molecules to date whose expression within the blood system is restricted to a small number of progenitor cells in the bone marrow.

Differentiation antigens expressed on B-lymphocytes and B-cell precursors. They are involved in regulation of B-cell proliferation.

A member of the tumor necrosis factor receptor superfamily with specificity for CD40 LIGAND. It is found on mature B-LYMPHOCYTES and some EPITHELIAL CELLS, lymphoid DENDRITIC CELLS. Evidence suggests that CD40-dependent activation of B-cells is important for generation of memory B-cells within the germinal centers. Mutations of the gene for CD40 antigen result in HYPER-IGM IMMUNODEFICIENCY SYNDROME, TYPE 3. Signaling of the receptor occurs through its association with TNF RECEPTOR-ASSOCIATED FACTORS.

A membrane glycoprotein and differentiation antigen expressed on the surface of T-cells that binds to CD40 ANTIGENS on B-LYMPHOCYTES and induces their proliferation. Mutation of the gene for CD40 ligand is a cause of HYPER-IGM IMMUNODEFICIENCY SYNDROME, TYPE 1.

Unglycosylated phosphoproteins expressed only on B-cells. They are regulators of transmembrane Ca2+ conductance and thought to play a role in B-cell activation and proliferation.

Substances elaborated by viruses that have antigenic activity.

Costimulatory T-LYMPHOCYTE receptors that have specificity for CD80 ANTIGEN and CD86 ANTIGEN. Activation of this receptor results in increased T-cell proliferation, cytokine production and promotion of T-cell survival.

Acidic sulfated integral membrane glycoproteins expressed in several alternatively spliced and variable glycosylated forms on a wide variety of cell types including mature T-cells, B-cells, medullary thymocytes, granulocytes, macrophages, erythrocytes, and fibroblasts. CD44 antigens are the principle cell surface receptors for hyaluronate and this interaction mediates binding of lymphocytes to high endothelial venules. (From Abbas et al., Cellular and Molecular Immunology, 2d ed, p156)

Differentiation antigens expressed on pluripotential hematopoietic cells, most human thymocytes, and a major subset of peripheral blood T-lymphocytes. They have been implicated in integrin-mediated cellular adhesion and as signalling receptors on T-cells.

Glycolipid-anchored membrane glycoproteins expressed on cells of the myelomonocyte lineage including monocytes, macrophages, and some granulocytes. They function as receptors for the complex of lipopolysaccharide (LPS) and LPS-binding protein.

Glycoprotein members of the immunoglobulin superfamily which participate in T-cell adhesion and activation. They are expressed on most peripheral T-lymphocytes, natural killer cells, and thymocytes, and function as co-receptors or accessory molecules in the T-cell receptor complex.

Ratio of T-LYMPHOCYTES that express the CD4 ANTIGEN to those that express the CD8 ANTIGEN. This value is commonly assessed in the diagnosis and staging of diseases affecting the IMMUNE SYSTEM including HIV INFECTIONS.

Glycoproteins expressed on all mature T-cells, thymocytes, and a subset of mature B-cells. Antibodies specific for CD5 can enhance T-cell receptor-mediated T-cell activation. The B-cell-specific molecule CD72 is a natural ligand for CD5. (From Abbas et al., Cellular and Molecular Immunology, 2d ed, p156)

Antigens expressed primarily on the membranes of living cells during sequential stages of maturation and differentiation. As immunologic markers they have high organ and tissue specificity and are useful as probes in studies of normal cell development as well as neoplastic transformation.

A critical subpopulation of T-lymphocytes involved in the induction of most immunological functions. The HIV virus has selective tropism for the T4 cell which expresses the CD4 phenotypic marker, a receptor for HIV. In fact, the key element in the profound immunosuppression seen in HIV infection is the depletion of this subset of T-lymphocytes.

Glycoproteins expressed on cortical thymocytes and on some dendritic cells and B-cells. Their structure is similar to that of MHC Class I and their function has been postulated as similar also. CD1 antigens are highly specific markers for human LANGERHANS CELLS.

Antibodies produced by a single clone of cells.

The 140 kDa isoform of NCAM (neural cell adhesion molecule) containing a transmembrane domain and short cytoplasmic tail. It is expressed by all lymphocytes mediating non-MHC restricted cytotoxicity and is present on some neural tissues and tumors.

Antigens expressed on the cell membrane of T-lymphocytes during differentiation, activation, and normal and neoplastic transformation. Their phenotypic characterization is important in differential diagnosis and studies of thymic ontogeny and T-cell function.

A membrane-bound or cytosolic enzyme that catalyzes the synthesis of CYCLIC ADP-RIBOSE (cADPR) from nicotinamide adenine dinucleotide (NAD). This enzyme generally catalyzes the hydrolysis of cADPR to ADP-RIBOSE, as well, and sometimes the synthesis of cyclic ADP-ribose 2' phosphate (2'-P-cADPR) from NADP.

Surface antigens expressed on myeloid cells of the granulocyte-monocyte-histiocyte series during differentiation. Analysis of their reactivity in normal and malignant myelomonocytic cells is useful in identifying and classifying human leukemias and lymphomas.

A costimulatory ligand expressed by ANTIGEN-PRESENTING CELLS that binds to CTLA-4 ANTIGEN with high specificity and to CD28 ANTIGEN with low specificity. The interaction of CD80 with CD28 ANTIGEN provides a costimulatory signal to T-LYMPHOCYTES, while its interaction with CTLA-4 ANTIGEN may play a role in inducing PERIPHERAL TOLERANCE.

Tetraspanin proteins found at high levels in cells of the lymphoid-myeloid lineage. CD53 antigens may be involved regulating the differentiation of T-LYMPHOCYTES and the activation of B-LYMPHOCYTES.

A cell adhesion protein that was originally identified as a heat stable antigen in mice. It is involved in METASTASIS and is highly expressed in many NEOPLASMS.

Zinc-binding metalloproteases that are members of the type II integral membrane metalloproteases. They are expressed by GRANULOCYTES; MONOCYTES; and their precursors as well as by various non-hematopoietic cells. They release an N-terminal amino acid from a peptide, amide or arylamide.

Any part or derivative of any protozoan that elicits immunity; malaria (Plasmodium) and trypanosome antigens are presently the most frequently encountered.

Lymphocytes responsible for cell-mediated immunity. Two types have been identified - cytotoxic (T-LYMPHOCYTES, CYTOTOXIC) and helper T-lymphocytes (T-LYMPHOCYTES, HELPER-INDUCER). They are formed when lymphocytes circulate through the THYMUS GLAND and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen.

A costimulatory ligand expressed by ANTIGEN-PRESENTING CELLS that binds to CD28 ANTIGEN with high specificity and to CTLA-4 ANTIGEN with low specificity. The interaction of CD86 with CD28 ANTIGEN provides a stimulatory signal to T-LYMPHOCYTES, while its interaction with CTLA-4 ANTIGEN may play a role in inducing PERIPHERAL TOLERANCE.

Technique using an instrument system for making, processing, and displaying one or more measurements on individual cells obtained from a cell suspension. Cells are usually stained with one or more fluorescent dyes specific to cell components of interest, e.g., DNA, and fluorescence of each cell is measured as it rapidly transverses the excitation beam (laser or mercury arc lamp). Fluorescence provides a quantitative measure of various biochemical and biophysical properties of the cell, as well as a basis for cell sorting. Other measurable optical parameters include light absorption and light scattering, the latter being applicable to the measurement of cell size, shape, density, granularity, and stain uptake.

Lymphoid cells concerned with humoral immunity. They are short-lived cells resembling bursa-derived lymphocytes of birds in their production of immunoglobulin upon appropriate stimulation.

Polyomavirus antigens which cause infection and cellular transformation. The large T antigen is necessary for the initiation of viral DNA synthesis, repression of transcription of the early region and is responsible in conjunction with the middle T antigen for the transformation of primary cells. Small T antigen is necessary for the completion of the productive infection cycle.

A tumor necrosis factor receptor subtype found in a variety of tissues and on activated LYMPHOCYTES. It has specificity for FAS LIGAND and plays a role in regulation of peripheral immune responses and APOPTOSIS. Multiple isoforms of the protein exist due to multiple ALTERNATIVE SPLICING. The activated receptor signals via a conserved death domain that associates with specific TNF RECEPTOR-ASSOCIATED FACTORS in the CYTOPLASM.

Antigens determined by leukocyte loci found on chromosome 6, the major histocompatibility loci in humans. They are polypeptides or glycoproteins found on most nucleated cells and platelets, determine tissue types for transplantation, and are associated with certain diseases.

Membrane antigens associated with maturation stages of B-lymphocytes, often expressed in tumors of B-cell origin.

High-molecular weight glycoproteins uniquely expressed on the surface of LEUKOCYTES and their hemopoietic progenitors. They contain a cytoplasmic protein tyrosine phosphatase activity which plays a role in intracellular signaling from the CELL SURFACE RECEPTORS. The CD45 antigens occur as multiple isoforms that result from alternative mRNA splicing and differential usage of three exons.

Process of classifying cells of the immune system based on structural and functional differences. The process is commonly used to analyze and sort T-lymphocytes into subsets based on CD antigens by the technique of flow cytometry.

Substances of fungal origin that have antigenic activity.

Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.

The major group of transplantation antigens in the mouse.

A 67-kDa sialic acid binding lectin that is specific for MYELOID CELLS and MONOCYTE-MACROPHAGE PRECURSOR CELLS. This protein is the smallest siglec subtype and contains a single immunoglobulin C2-set domain. It may play a role in intracellular signaling via its interaction with SHP-1 PROTEIN-TYROSINE PHOSPHATASE and SHP-2 PROTEIN-TYROSINE PHOSPHATASE.

Any part or derivative of a helminth that elicits an immune reaction. The most commonly seen helminth antigens are those of the schistosomes.

Molecules on the surface of T-lymphocytes that recognize and combine with antigens. The receptors are non-covalently associated with a complex of several polypeptides collectively called CD3 antigens (ANTIGENS, CD3). Recognition of foreign antigen and the major histocompatibility complex is accomplished by a single heterodimeric antigen-receptor structure, composed of either alpha-beta (RECEPTORS, ANTIGEN, T-CELL, ALPHA-BETA) or gamma-delta (RECEPTORS, ANTIGEN, T-CELL, GAMMA-DELTA) chains.

Cell-surface glycoprotein beta-chains that are non-covalently linked to specific alpha-chains of the CD11 family of leukocyte-adhesion molecules (RECEPTORS, LEUKOCYTE-ADHESION). A defect in the gene encoding CD18 causes LEUKOCYTE-ADHESION DEFICIENCY SYNDROME.

Morphologic alteration of small B LYMPHOCYTES or T LYMPHOCYTES in culture into large blast-like cells able to synthesize DNA and RNA and to divide mitotically. It is induced by INTERLEUKINS; MITOGENS such as PHYTOHEMAGGLUTININS, and by specific ANTIGENS. It may also occur in vivo as in GRAFT REJECTION.

A member of the tumor necrosis factor receptor superfamily that may play a role in the regulation of NF-KAPPA B and APOPTOSIS. They are found on activated T-LYMPHOCYTES; B-LYMPHOCYTES; NEUTROPHILS; EOSINOPHILS; MAST CELLS and NK CELLS. Overexpression of CD30 antigen in hematopoietic malignancies make the antigen clinically useful as a biological tumor marker. Signaling of the receptor occurs through its association with TNF RECEPTOR-ASSOCIATED FACTORS.

Glycoproteins found on the membrane or surface of cells.

A critical subpopulation of regulatory T-lymphocytes involved in MHC Class I-restricted interactions. They include both cytotoxic T-lymphocytes (T-LYMPHOCYTES, CYTOTOXIC) and CD8+ suppressor T-lymphocytes.

Sites on an antigen that interact with specific antibodies.

A subtype of tetraspanin proteins that play a role in cell adhesion, cell motility, and tumor metastasis. CD9 antigens take part in the process of platelet activation and aggregation, the formation of paranodal junctions in neuronal tissue, and the fusion of sperm with egg.

A glycoprotein that is secreted into the luminal surface of the epithelia in the gastrointestinal tract. It is found in the feces and pancreaticobiliary secretions and is used to monitor the response to colon cancer treatment.

A subclass of HLA-D antigens that consist of alpha and beta chains. The inheritance of HLA-DR antigens differs from that of the HLA-DQ ANTIGENS and HLA-DP ANTIGENS.

A trisaccharide antigen expressed on glycolipids and many cell-surface glycoproteins. In the blood the antigen is found on the surface of NEUTROPHILS; EOSINOPHILS; and MONOCYTES. In addition, CD15 antigen is a stage-specific embryonic antigen.

Those proteins recognized by antibodies from serum of animals bearing tumors induced by viruses; these proteins are presumably coded for by the nucleic acids of the same viruses that caused the neoplastic transformation.

Established cell cultures that have the potential to propagate indefinitely.

A sialic acid-rich protein and an integral cell membrane mucin. It plays an important role in activation of T-LYMPHOCYTES.

Leukocyte differentiation antigens and major platelet membrane glycoproteins present on MONOCYTES; ENDOTHELIAL CELLS; PLATELETS; and mammary EPITHELIAL CELLS. They play major roles in CELL ADHESION; SIGNAL TRANSDUCTION; and regulation of angiogenesis. CD36 is a receptor for THROMBOSPONDINS and can act as a scavenger receptor that recognizes and transports oxidized LIPOPROTEINS and FATTY ACIDS.

The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.

A group of three different alpha chains (CD11a, CD11b, CD11c) that are associated with an invariant CD18 beta chain (ANTIGENS, CD18). The three resulting leukocyte-adhesion molecules (RECEPTORS, LEUKOCYTE ADHESION) are LYMPHOCYTE FUNCTION-ASSOCIATED ANTIGEN-1; MACROPHAGE-1 ANTIGEN; and ANTIGEN, P150,95.

Large, transmembrane, non-covalently linked glycoproteins (alpha and beta). Both chains can be polymorphic although there is more structural variation in the beta chains. The class II antigens in humans are called HLA-D ANTIGENS and are coded by a gene on chromosome 6. In mice, two genes named IA and IE on chromosome 17 code for the H-2 antigens. The antigens are found on B-lymphocytes, macrophages, epidermal cells, and sperm and are thought to mediate the competence of and cellular cooperation in the immune response. The term IA antigens used to refer only to the proteins encoded by the IA genes in the mouse, but is now used as a generic term for any class II histocompatibility antigen.

A group of antigens that includes both the major and minor histocompatibility antigens. The former are genetically determined by the major histocompatibility complex. They determine tissue type for transplantation and cause allograft rejections. The latter are systems of allelic alloantigens that can cause weak transplant rejection.

Small glycoproteins found on both hematopoietic and non-hematopoietic cells. CD59 restricts the cytolytic activity of homologous complement by binding to C8 and C9 and blocking the assembly of the membrane attack complex. (From Barclay et al., The Leukocyte Antigen FactsBook, 1993, p234)

IMMUNOGLOBULINS on the surface of B-LYMPHOCYTES. Their MESSENGER RNA contains an EXON with a membrane spanning sequence, producing immunoglobulins in the form of type I transmembrane proteins as opposed to secreted immunoglobulins (ANTIBODIES) which do not contain the membrane spanning segment.

Nuclear antigen with a role in DNA synthesis, DNA repair, and cell cycle progression. PCNA is required for the coordinated synthesis of both leading and lagging strands at the replication fork during DNA replication. PCNA expression correlates with the proliferation activity of several malignant and non-malignant cell types.

Oligosaccharide antigenic determinants found principally on NK cells and T-cells. Their role in the immune response is poorly understood.

A transmembrane protein belonging to the tumor necrosis factor superfamily that specifically binds to CD27 ANTIGEN. It is found on activated T-LYMPHOCYTES; B-LYMPHOCYTES; and DENDRITIC CELLS where it plays a role in stimulating the proliferation of CD4-POSITIVE T-LYMPHOCYTES and CD8-POSITIVE T-LYMPHOCYTES.

A ubiquitously expressed complement receptor that binds COMPLEMENT C3B and COMPLEMENT C4B and serves as a cofactor for their inactivation. CD46 also interacts with a wide variety of pathogens and mediates immune response.

A class of animal lectins that bind to carbohydrate in a calcium-dependent manner. They share a common carbohydrate-binding domain that is structurally distinct from other classes of lectins.

Glycoproteins with a wide distribution on hematopoietic and non-hematopoietic cells and strongly expressed on macrophages. CD58 mediates cell adhesion by binding to CD2; (ANTIGENS, CD2); and this enhances antigen-specific T-cell activation.

55-kDa antigens found on HELPER-INDUCER T-LYMPHOCYTES and on a variety of other immune cell types. CD4 antigens are members of the immunoglobulin supergene family and are implicated as associative recognition elements in MAJOR HISTOCOMPATIBILITY COMPLEX class II-restricted immune responses. On T-lymphocytes they define the helper/inducer subset. CD4 antigens also serve as INTERLEUKIN-15 receptors and bind to the HIV receptors, binding directly to the HIV ENVELOPE PROTEIN GP120.

A ubiquitously expressed membrane glycoprotein. It interacts with a variety of INTEGRINS and mediates responses to EXTRACELLULAR MATRIX PROTEINS.

A CD antigen that contains a conserved I domain which is involved in ligand binding. When combined with CD18 the two subunits form MACROPHAGE-1 ANTIGEN.

The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.

A glycoprotein that is a kallikrein-like serine proteinase and an esterase, produced by epithelial cells of both normal and malignant prostate tissue. It is an important marker for the diagnosis of prostate cancer.

An integrin alpha subunit of approximately 150-kDa molecular weight. It is expressed at high levels on monocytes and combines with CD18 ANTIGEN to form the cell surface receptor INTEGRIN ALPHAXBETA2. The subunit contains a conserved I-domain which is characteristic of several of alpha integrins.

The lipopolysaccharide-protein somatic antigens, usually from gram-negative bacteria, important in the serological classification of enteric bacilli. The O-specific chains determine the specificity of the O antigens of a given serotype. O antigens are the immunodominant part of the lipopolysaccharide molecule in the intact bacterial cell. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)

A specific HLA-A surface antigen subtype. Members of this subtype contain alpha chains that are encoded by the HLA-A*02 allele family.

An immunoassay utilizing an antibody labeled with an enzyme marker such as horseradish peroxidase. While either the enzyme or the antibody is bound to an immunosorbent substrate, they both retain their biologic activity; the change in enzyme activity as a result of the enzyme-antibody-antigen reaction is proportional to the concentration of the antigen and can be measured spectrophotometrically or with the naked eye. Many variations of the method have been developed.

Histochemical localization of immunoreactive substances using labeled antibodies as reagents.

Progenitor cells from which all blood cells derive.

The number of CD4-POSITIVE T-LYMPHOCYTES per unit volume of BLOOD. Determination requires the use of a fluorescence-activated flow cytometer.

The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of IgG, for example, IgG1, IgG2A, and IgG2B.

Carbohydrate antigens expressed by malignant tissue. They are useful as tumor markers and are measured in the serum by means of a radioimmunoassay employing monoclonal antibodies.

GPI-linked membrane proteins broadly distributed among hematopoietic and non-hematopoietic cells. CD55 prevents the assembly of C3 CONVERTASE or accelerates the disassembly of preformed convertase, thus blocking the formation of the membrane attack complex.

Cell adhesion molecules present on virtually all monocytes, platelets, and granulocytes. CD31 is highly expressed on endothelial cells and concentrated at the junctions between them.

Cells grown in vitro from neoplastic tissue. If they can be established as a TUMOR CELL LINE, they can be propagated in cell culture indefinitely.

Membrane glycoproteins consisting of an alpha subunit and a BETA 2-MICROGLOBULIN beta subunit. In humans, highly polymorphic genes on CHROMOSOME 6 encode the alpha subunits of class I antigens and play an important role in determining the serological specificity of the surface antigen. Class I antigens are found on most nucleated cells and are generally detected by their reactivity with alloantisera. These antigens are recognized during GRAFT REJECTION and restrict cell-mediated lysis of virus-infected cells.

Tetraspanin proteins that are involved in a variety of cellular functions including BASEMENT MEMBRANE assembly, and in the formation of a molecular complexes on the surface of LYMPHOCYTES.

Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.

A member of the tumor necrosis factor receptor superfamily that is specific for 4-1BB LIGAND. It is found in a variety of immune cell types including activated T-LYMPHOCYTES; NATURAL KILLER CELLS; and DENDRITIC CELLS. Activation of the receptor on T-LYMPHOCYTES plays a role in their expansion, production of cytokines and survival. Signaling by the activated receptor occurs through its association with TNF RECEPTOR-ASSOCIATED FACTORS.

Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.

Proteins prepared by recombinant DNA technology.

White blood cells formed in the body's lymphoid tissue. The nucleus is round or ovoid with coarse, irregularly clumped chromatin while the cytoplasm is typically pale blue with azurophilic (if any) granules. Most lymphocytes can be classified as either T or B (with subpopulations of each), or NATURAL KILLER CELLS.

Large, phagocytic mononuclear leukocytes produced in the vertebrate BONE MARROW and released into the BLOOD; contain a large, oval or somewhat indented nucleus surrounded by voluminous cytoplasm and numerous organelles.

Polymorphic class I human histocompatibility (HLA) surface antigens present on almost all nucleated cells. At least 20 antigens have been identified which are encoded by the A locus of multiple alleles on chromosome 6. They serve as targets for T-cell cytolytic responses and are involved with acceptance or rejection of tissue/organ grafts.

Serological reactions in which an antiserum against one antigen reacts with a non-identical but closely related antigen.

Specialized cells of the hematopoietic system that have branch-like extensions. They are found throughout the lymphatic system, and in non-lymphoid tissues such as SKIN and the epithelia of the intestinal, respiratory, and reproductive tracts. They trap and process ANTIGENS, and present them to T-CELLS, thereby stimulating CELL-MEDIATED IMMUNITY. They are different from the non-hematopoietic FOLLICULAR DENDRITIC CELLS, which have a similar morphology and immune system function, but with respect to humoral immunity (ANTIBODY PRODUCTION).

Receptors present on activated T-LYMPHOCYTES and B-LYMPHOCYTES that are specific for INTERLEUKIN-2 and play an important role in LYMPHOCYTE ACTIVATION. They are heterotrimeric proteins consisting of the INTERLEUKIN-2 RECEPTOR ALPHA SUBUNIT, the INTERLEUKIN-2 RECEPTOR BETA SUBUNIT, and the INTERLEUKIN RECEPTOR COMMON GAMMA-CHAIN.

Sets of cell surface antigens located on BLOOD CELLS. They are usually membrane GLYCOPROTEINS or GLYCOLIPIDS that are antigenically distinguished by their carbohydrate moieties.

Those hepatitis B antigens found on the surface of the Dane particle and on the 20 nm spherical and tubular particles. Several subspecificities of the surface antigen are known. These were formerly called the Australia antigen.

Ubiquitously-expressed tetraspanin proteins that are found in late ENDOSOMES and LYSOSOMES and have been implicated in intracellular transport of proteins.

The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES.

The property of antibodies which enables them to react with some ANTIGENIC DETERMINANTS and not with others. Specificity is dependent on chemical composition, physical forces, and molecular structure at the binding site.

Tetraspanin proteins found associated with LAMININ-binding INTEGRINS. The CD151 antigens may play a role in the regulation of CELL MOTILITY.

A component of the B-cell antigen receptor that is involved in B-cell antigen receptor heavy chain transport to the PLASMA MEMBRANE. It is expressed almost exclusively in B-LYMPHOCYTES and serves as a useful marker for B-cell NEOPLASMS.

An encapsulated lymphatic organ through which venous blood filters.

Test for tissue antigen using either a direct method, by conjugation of antibody with fluorescent dye (FLUORESCENT ANTIBODY TECHNIQUE, DIRECT) or an indirect method, by formation of antigen-antibody complex which is then labeled with fluorescein-conjugated anti-immunoglobulin antibody (FLUORESCENT ANTIBODY TECHNIQUE, INDIRECT). The tissue is then examined by fluorescence microscopy.

Human immune-response or Class II antigens found mainly, but not exclusively, on B-lymphocytes and produced from genes of the HLA-D locus. They are extremely polymorphic families of glycopeptides, each consisting of two chains, alpha and beta. This group of antigens includes the -DR, -DQ and -DP designations, of which HLA-DR is most studied; some of these glycoproteins are associated with certain diseases, possibly of immune etiology.

A membrane-bound tumor necrosis family member found primarily on activated T-LYMPHOCYTES that binds specifically to CD30 ANTIGEN. It may play a role in INFLAMMATION and immune regulation.

The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.

A class of enzymes involved in the hydrolysis of the N-glycosidic bond of nitrogen-linked sugars.

A form of undifferentiated malignant LYMPHOMA usually found in central Africa, but also reported in other parts of the world. It is commonly manifested as a large osteolytic lesion in the jaw or as an abdominal mass. B-cell antigens are expressed on the immature cells that make up the tumor in virtually all cases of Burkitt lymphoma. The Epstein-Barr virus (HERPESVIRUS 4, HUMAN) has been isolated from Burkitt lymphoma cases in Africa and it is implicated as the causative agent in these cases; however, most non-African cases are EBV-negative.

Molecules on the surface of B- and T-lymphocytes that recognize and combine with specific antigens.

Deliberate stimulation of the host's immune response. ACTIVE IMMUNIZATION involves administration of ANTIGENS or IMMUNOLOGIC ADJUVANTS. PASSIVE IMMUNIZATION involves administration of IMMUNE SERA or LYMPHOCYTES or their extracts (e.g., transfer factor, immune RNA) or transplantation of immunocompetent cell producing tissue (thymus or bone marrow).

The production of ANTIBODIES by proliferating and differentiated B-LYMPHOCYTES under stimulation by ANTIGENS.

An alpha-integrin subunit found on lymphocytes, granulocytes, macrophages and monocytes. It combines with the integrin beta2 subunit (CD18 ANTIGEN) to form LYMPHOCYTE FUNCTION-ASSOCIATED ANTIGEN-1.

RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.

Antigens of the virion of the HEPATITIS B VIRUS or the Dane particle, its surface (HEPATITIS B SURFACE ANTIGENS), core (HEPATITIS B CORE ANTIGENS), and other associated antigens, including the HEPATITIS B E ANTIGENS.

The soft tissue filling the cavities of bones. Bone marrow exists in two types, yellow and red. Yellow marrow is found in the large cavities of large bones and consists mostly of fat cells and a few primitive blood cells. Red marrow is a hematopoietic tissue and is the site of production of erythrocytes and granular leukocytes. Bone marrow is made up of a framework of connective tissue containing branching fibers with the frame being filled with marrow cells.

The processes triggered by interactions of ANTIBODIES with their ANTIGENS.

Serum that contains antibodies. It is obtained from an animal that has been immunized either by ANTIGEN injection or infection with microorganisms containing the antigen.

The relatively long-lived phagocytic cell of mammalian tissues that are derived from blood MONOCYTES. Main types are PERITONEAL MACROPHAGES; ALVEOLAR MACROPHAGES; HISTIOCYTES; KUPFFER CELLS of the liver; and OSTEOCLASTS. They may further differentiate within chronic inflammatory lesions to EPITHELIOID CELLS or may fuse to form FOREIGN BODY GIANT CELLS or LANGHANS GIANT CELLS. (from The Dictionary of Cell Biology, Lackie and Dow, 3rd ed.)

Mice homozygous for the mutant autosomal recessive gene "scid" which is located on the centromeric end of chromosome 16. These mice lack mature, functional lymphocytes and are thus highly susceptible to lethal opportunistic infections if not chronically treated with antibiotics. The lack of B- and T-cell immunity resembles severe combined immunodeficiency (SCID) syndrome in human infants. SCID mice are useful as animal models since they are receptive to implantation of a human immune system producing SCID-human (SCID-hu) hematochimeric mice.

Immunized T-lymphocytes which can directly destroy appropriate target cells. These cytotoxic lymphocytes may be generated in vitro in mixed lymphocyte cultures (MLC), in vivo during a graft-versus-host (GVH) reaction, or after immunization with an allograft, tumor cell or virally transformed or chemically modified target cell. The lytic phenomenon is sometimes referred to as cell-mediated lympholysis (CML). These CD8-positive cells are distinct from NATURAL KILLER CELLS and NATURAL KILLER T-CELLS. There are two effector phenotypes: TC1 and TC2.

Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.

The fission of a CELL. It includes CYTOKINESIS, when the CYTOPLASM of a cell is divided, and CELL NUCLEUS DIVISION.

A heterogeneous group of immunocompetent cells that mediate the cellular immune response by processing and presenting antigens to the T-cells. Traditional antigen-presenting cells include MACROPHAGES; DENDRITIC CELLS; LANGERHANS CELLS; and B-LYMPHOCYTES. FOLLICULAR DENDRITIC CELLS are not traditional antigen-presenting cells, but because they hold antigen on their cell surface in the form of IMMUNE COMPLEXES for B-cell recognition they are considered so by some authors.

The type species of LYMPHOCRYPTOVIRUS, subfamily GAMMAHERPESVIRINAE, infecting B-cells in humans. It is thought to be the causative agent of INFECTIOUS MONONUCLEOSIS and is strongly associated with oral hairy leukoplakia (LEUKOPLAKIA, HAIRY;), BURKITT LYMPHOMA; and other malignancies.

T-cell receptors composed of CD3-associated alpha and beta polypeptide chains and expressed primarily in CD4+ or CD8+ T-cells. Unlike immunoglobulins, the alpha-beta T-cell receptors recognize antigens only when presented in association with major histocompatibility (MHC) molecules.

Immunoglobulins produced in a response to BACTERIAL ANTIGENS.

Class I human histocompatibility (HLA) surface antigens encoded by more than 30 detectable alleles on locus B of the HLA complex, the most polymorphic of all the HLA specificities. Several of these antigens (e.g., HLA-B27, -B7, -B8) are strongly associated with predisposition to rheumatoid and other autoimmune disorders. Like other class I HLA determinants, they are involved in the cellular immune reactivity of cytolytic T lymphocytes.

The altered state of immunologic responsiveness resulting from initial contact with antigen, which enables the individual to produce antibodies more rapidly and in greater quantity in response to secondary antigenic stimulus.

Cells contained in the bone marrow including fat cells (see ADIPOCYTES); STROMAL CELLS; MEGAKARYOCYTES; and the immediate precursors of most blood cells.

The phenomenon of target cell destruction by immunologically active effector cells. It may be brought about directly by sensitized T-lymphocytes or by lymphoid or myeloid "killer" cells, or it may be mediated by cytotoxic antibody, cytotoxic factor released by lymphoid cells, or complement.

Laboratory mice that have been produced from a genetically manipulated EGG or EMBRYO, MAMMALIAN.

A melanosome-specific protein that plays a role in the expression, stability, trafficking, and processing of GP100 MELANOMA ANTIGEN, which is critical to the formation of Stage II MELANOSOMES. The protein is used as an antigen marker for MELANOMA cells.

A widely distributed cell surface transmembrane glycoprotein that stimulates the synthesis of MATRIX METALLOPROTEINASES. It is found at high levels on the surface of malignant NEOPLASMS and may play a role as a mediator of malignant cell behavior.

A general term for various neoplastic diseases of the lymphoid tissue.

An albumin obtained from the white of eggs. It is a member of the serpin superfamily.

Antigens associated with specific proteins of the human adult T-cell immunodeficiency virus (HIV); also called HTLV-III-associated and lymphadenopathy-associated virus (LAV) antigens.

An inhibitory T CELL receptor that is closely related to CD28 ANTIGEN. It has specificity for CD80 ANTIGEN and CD86 ANTIGEN and acts as a negative regulator of peripheral T cell function. CTLA-4 antigen is believed to play role in inducing PERIPHERAL TOLERANCE.

A promyelocytic cell line derived from a patient with ACUTE PROMYELOCYTIC LEUKEMIA. HL-60 cells lack specific markers for LYMPHOID CELLS but express surface receptors for FC FRAGMENTS and COMPLEMENT SYSTEM PROTEINS. They also exhibit phagocytic activity and responsiveness to chemotactic stimuli. (From Hay et al., American Type Culture Collection, 7th ed, pp127-8)

A widely expressed transmembrane glycoprotein that functions as a METASTASIS suppressor protein. It is underexpressed in a variety of human NEOPLASMS.

Immunologic techniques based on the use of: (1) enzyme-antibody conjugates; (2) enzyme-antigen conjugates; (3) antienzyme antibody followed by its homologous enzyme; or (4) enzyme-antienzyme complexes. These are used histologically for visualizing or labeling tissue specimens.

Immunoglobulin molecules having a specific amino acid sequence by virtue of which they interact only with the ANTIGEN (or a very similar shape) that induced their synthesis in cells of the lymphoid series (especially PLASMA CELLS).

The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.

A group of differentiation surface antigens, among the first to be discovered on thymocytes and T-lymphocytes. Originally identified in the mouse, they are also found in other species including humans, and are expressed on brain neurons and other cells.

Non-antibody proteins secreted by inflammatory leukocytes and some non-leukocytic cells, that act as intercellular mediators. They differ from classical hormones in that they are produced by a number of tissue or cell types rather than by specialized glands. They generally act locally in a paracrine or autocrine rather than endocrine manner.

The specific failure of a normally responsive individual to make an immune response to a known antigen. It results from previous contact with the antigen by an immunologically immature individual (fetus or neonate) or by an adult exposed to extreme high-dose or low-dose antigen, or by exposure to radiation, antimetabolites, antilymphocytic serum, etc.

Manifestations of the immune response which are mediated by antigen-sensitized T-lymphocytes via lymphokines or direct cytotoxicity. This takes place in the absence of circulating antibody or where antibody plays a subordinate role.

A single, unpaired primary lymphoid organ situated in the MEDIASTINUM, extending superiorly into the neck to the lower edge of the THYROID GLAND and inferiorly to the fourth costal cartilage. It is necessary for normal development of immunologic function early in life. By puberty, it begins to involute and much of the tissue is replaced by fat.

Endogenous tissue constituents that have the ability to interact with AUTOANTIBODIES and cause an immune response.

A group of genetically identical cells all descended from a single common ancestral cell by mitosis in eukaryotes or by binary fission in prokaryotes. Clone cells also include populations of recombinant DNA molecules all carrying the same inserted sequence. (From King & Stansfield, Dictionary of Genetics, 4th ed)

Nuclear antigens encoded by VIRAL GENES found in HUMAN HERPESVIRUS 4. At least six nuclear antigens have been identified.

A soluble substance elaborated by antigen- or mitogen-stimulated T-LYMPHOCYTES which induces DNA synthesis in naive lymphocytes.

A class of immunoglobulin bearing mu chains (IMMUNOGLOBULIN MU-CHAINS). IgM can fix COMPLEMENT. The name comes from its high molecular weight and originally being called a macroglobulin.

A cell line derived from cultured tumor cells.

Measurable and quantifiable biological parameters (e.g., specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.

A sex-specific cell surface antigen produced by the sex-determining gene of the Y chromosome in mammals. It causes syngeneic grafts from males to females to be rejected and interacts with somatic elements of the embryologic undifferentiated gonad to produce testicular organogenesis.

A cell adhesion molecule of the immunoglobulin superfamily that is expressed in ENDOTHELIAL CELLS and is involved in INTERCELLULAR JUNCTIONS.

Antigens stimulating the formation of, or combining with heterophile antibodies. They are cross-reacting antigens found in phylogenetically unrelated species.

CD4-positive T cells that inhibit immunopathology or autoimmune disease in vivo. They inhibit the immune response by influencing the activity of other cell types. Regulatory T-cells include naturally occurring CD4+CD25+ cells, IL-10 secreting Tr1 cells, and Th3 cells.

Antibodies obtained from a single clone of cells grown in mice or rats.

Antigenic determinants recognized and bound by the T-cell receptor. Epitopes recognized by the T-cell receptor are often located in the inner, unexposed side of the antigen, and become accessible to the T-cell receptors after proteolytic processing of the antigen.

The major interferon produced by mitogenically or antigenically stimulated LYMPHOCYTES. It is structurally different from TYPE I INTERFERON and its major activity is immunoregulation. It has been implicated in the expression of CLASS II HISTOCOMPATIBILITY ANTIGENS in cells that do not normally produce them, leading to AUTOIMMUNE DISEASES.

A heterodimeric protein that is a cell surface antigen associated with lymphocyte activation. The initial characterization of this protein revealed one identifiable heavy chain (ANTIGENS, CD98 HEAVY CHAIN) and an indeterminate smaller light chain. It is now known that a variety of light chain subunits (ANTIGENS, CD98 LIGHT CHAINS) can dimerize with the heavy chain. Depending upon its light chain composition a diverse array of functions can be found for this protein. Functions include: type L amino acid transport, type y+L amino acid transport and regulation of cellular fusion.

The hepatitis B antigen within the core of the Dane particle, the infectious hepatitis virion.

Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.

The complex formed by the binding of antigen and antibody molecules. The deposition of large antigen-antibody complexes leading to tissue damage causes IMMUNE COMPLEX DISEASES.

They are oval or bean shaped bodies (1 - 30 mm in diameter) located along the lymphatic system.

The sum of the weight of all the atoms in a molecule.

Technique involving the diffusion of antigen or antibody through a semisolid medium, usually agar or agarose gel, with the result being a precipitin reaction.

A group of the D-related HLA antigens found to differ from the DR antigens in genetic locus and therefore inheritance. These antigens are polymorphic glycoproteins comprising alpha and beta chains and are found on lymphoid and other cells, often associated with certain diseases.

Immunoglobulins produced in response to VIRAL ANTIGENS.

The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.

Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations, or by parent x offspring matings carried out with certain restrictions. All animals within an inbred strain trace back to a common ancestor in the twentieth generation.

A glycolipid, cross-species antigen that induces production of antisheep hemolysin. It is present on the tissue cells of many species but absent in humans. It is found in many infectious agents.

Elements of limited time intervals, contributing to particular results or situations.

The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.

An inhibitory B7 antigen that has specificity for the T-CELL receptor PROGRAMMED CELL DEATH 1 PROTEIN. CD274 antigen provides negative signals that control and inhibit T-cell responses and is found at higher than normal levels on tumor cells, suggesting its potential role in TUMOR IMMUNE EVASION.

Serologic tests based on inactivation of complement by the antigen-antibody complex (stage 1). Binding of free complement can be visualized by addition of a second antigen-antibody system such as red cells and appropriate red cell antibody (hemolysin) requiring complement for its completion (stage 2). Failure of the red cells to lyse indicates that a specific antigen-antibody reaction has taken place in stage 1. If red cells lyse, free complement is present indicating no antigen-antibody reaction occurred in stage 1.

A species of POLYOMAVIRUS originally isolated from Rhesus monkey kidney tissue. It produces malignancy in human and newborn hamster kidney cell cultures.

Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.

Substances that augment, stimulate, activate, potentiate, or modulate the immune response at either the cellular or humoral level. The classical agents (Freund's adjuvant, BCG, Corynebacterium parvum, et al.) contain bacterial antigens. Some are endogenous (e.g., histamine, interferon, transfer factor, tuftsin, interleukin-1). Their mode of action is either non-specific, resulting in increased immune responsiveness to a wide variety of antigens, or antigen-specific, i.e., affecting a restricted type of immune response to a narrow group of antigens. The therapeutic efficacy of many biological response modifiers is related to their antigen-specific immunoadjuvanticity.

Antigens that exist in alternative (allelic) forms in a single species. When an isoantigen is encountered by species members who lack it, an immune response is induced. Typical isoantigens are the BLOOD GROUP ANTIGENS.

Cells artificially created by fusion of activated lymphocytes with neoplastic cells. The resulting hybrid cells are cloned and produce pure MONOCLONAL ANTIBODIES or T-cell products, identical to those produced by the immunologically competent parent cell.

A melanosome-associated protein that plays a role in the maturation of the MELANOSOME.

The genetic region which contains the loci of genes which determine the structure of the serologically defined (SD) and lymphocyte-defined (LD) TRANSPLANTATION ANTIGENS, genes which control the structure of the IMMUNE RESPONSE-ASSOCIATED ANTIGENS, HUMAN; the IMMUNE RESPONSE GENES which control the ability of an animal to respond immunologically to antigenic stimuli, and genes which determine the structure and/or level of the first four components of complement.

Bone marrow-derived lymphocytes that possess cytotoxic properties, classically directed against transformed and virus-infected cells. Unlike T CELLS; and B CELLS; NK CELLS are not antigen specific. The cytotoxicity of natural killer cells is determined by the collective signaling of an array of inhibitory and stimulatory CELL SURFACE RECEPTORS. A subset of T-LYMPHOCYTES referred to as NATURAL KILLER T CELLS shares some of the properties of this cell type.

A technique that combines protein electrophoresis and double immunodiffusion. In this procedure proteins are first separated by gel electrophoresis (usually agarose), then made visible by immunodiffusion of specific antibodies. A distinct elliptical precipitin arc results for each protein detectable by the antisera.

Form of passive immunization where previously sensitized immunologic agents (cells or serum) are transferred to non-immune recipients. When transfer of cells is used as a therapy for the treatment of neoplasms, it is called adoptive immunotherapy (IMMUNOTHERAPY, ADOPTIVE).

Selective tetraspan-integrin complexes (CD81/alpha4beta1, CD151/alpha3beta1, CD151/alpha6beta1) under conditions disrupting tetraspan interactions. (1/333)

The tetraspans are molecules with four transmembrane domains which are engaged in multimolecular complexes (the tetraspan web) containing a subset of beta1 integrins (in particular alpha3beta1, alpha4beta1 and alpha6beta1), MHC antigens and several unidentified molecules. The molecules associated with tetraspans are readily detected after immunoprecipitation performed in mild detergents such as Brij 97 or CHAPS. In this study we show that another classical mild detergent, digitonin, dissociated most of these associated molecules, including integrins, from the tetraspans CD9, CD37, CD53, CD63, CD82, Co-029, Talla-1 and NAG-2. In contrast, reciprocal immunoprecipitations from various cell lines demonstrated that two other tetraspans, CD81 and CD151, formed complexes with integrins not disrupted by digitonin. These complexes were CD81/alpha4beta1, CD151/alpha3beta1 and CD151/alpha6beta1. Furthermore, a new anti-CD151 monoclonal antibody (mAb), TS151r, was shown to have a restricted pattern of expression, inversely related to the sum of the levels of expression of alpha6beta1 and alpha3beta1. This mAb was unable to co-precipitate integrins in digitonin, suggesting that its epitope is blocked by the association with integrins. Indeed, the binding of TS151r to the cell surface was quantitatively diminished following alpha3beta1 overexpression. Altogether, these data suggest that, among tetraspans, CD81 interacts directly with the integrin alpha4beta1, and CD151 interacts directly with integrins alpha3beta1 and alpha6beta1. Because all tetraspan-tetraspan associations are disrupted by digitonin, it is likely that the other tetraspans interact indirectly with integrins, through interactions with CD81 or CD151. (+info)

Characterization of hepatitis C virus E2 glycoprotein interaction with a putative cellular receptor, CD81. (2/333)

A truncated soluble form of the hepatitis C virus E2 glycoprotein, E2661, binds specifically to the surface of cells expressing human CD81 (hCD81) but not other members of the tetraspanin family (CD9, CD63, and CD151). No differences were noted between the level of E2661 binding to hCD81 expressed on the surface of rat RBL or KM3 cells compared to Daudi and Molt-4 cells, suggesting that additional human-cell-specific factors are not required for the primary interaction of E2 with the cell surface. E2 did not interact with African green monkey (AGM) CD81 on the surface of COS cells, which differs from the hCD81 sequence at four residues within the second extracellular region (EC2) (amino acids [aa] 163, 186, 188, and 196), suggesting that one or more of these residues defines the site of interaction with E2. Various recombinant forms of CD81 EC2 show differences in the ability to bind E2, suggesting that CD81 conformation is important for E2 recognition. Regions of E2 involved in the CD81 interaction were analyzed, and our data suggest that the binding site is of a conformational nature involving aa 480 to 493 and 544 to 551 within the E2 glycoprotein. Finally, we demonstrate that ligation of CD81 by E2661 induced aggregation of lymphoid cells and inhibited B-cell proliferation, demonstrating that E2 interaction with CD81 can modulate cell function. (+info)

Functional analysis of cell surface-expressed hepatitis C virus E2 glycoprotein. (3/333)

Hepatitis C virus (HCV) glycoproteins E1 and E2, when expressed in eukaryotic cells, are retained in the endoplasmic reticulum (ER). C-terminal truncation of E2 at residue 661 or 715 (position on the polyprotein) leads to secretion, consistent with deletion of a proposed hydrophobic transmembrane anchor sequence. We demonstrate cell surface expression of a chimeric glycoprotein consisting of E2 residues 384 to 661 fused to the transmembrane and cytoplasmic domains of influenza A virus hemagglutinin (HA), termed E2661-HATMCT. The E2661-HATMCT chimeric glycoprotein was able to bind a number of conformation-dependent monoclonal antibodies and a recombinant soluble form of CD81, suggesting that it was folded in a manner comparable to "native" E2. Furthermore, cell surface-expressed E2661-HATMCT demonstrated pH-dependent changes in antigen conformation, consistent with an acid-mediated fusion mechanism. However, E2661-HATMCT was unable to induce cell fusion of CD81-positive HEK cells after neutral- or low-pH treatment. We propose that a stretch of conserved, hydrophobic amino acids within the E1 glycoprotein, displaying similarities to flavivirus and paramyxovirus fusion peptides, may constitute the HCV fusion peptide. We demonstrate that influenza virus can incorporate E2661-HATMCT into particles and discuss experiments to address the relevance of the E2-CD81 interaction for HCV attachment and entry. (+info)

Finding the right RNA: identification of cellular mRNA substrates for RNA-binding proteins. (4/333)

Defects in RNA-binding proteins have been implicated in human genetic disorders. However, efforts in understanding the functions of these proteins have been hampered by the inability to obtain their mRNA substrates. To identify cognate cellular mRNAs associated with an RNA-binding protein, we devised a strategy termed isolation of specific nucleic acids associated with proteins (SNAAP). The SNAAP technique allows isolation and subsequent identification of these mRNAs. To assess the validity of this approach, we utilized cellular mRNA and protein from K562 cells and alphaCP1, a protein implicated in a-globin mRNA stability, as a model system. Immobilization of an RNA-binding protein with the glutathione-S-transferase (GST) domain enables isolation of mRNA within an mRNP context and the identity of the bound mRNAs is determined by the differential display assay. The specificity of protein-RNA interactions was considerably enhanced when the interactions were carried out in the presence of cellular extract rather than purified components. Two of the mRNAs specifically bound by alphaCP1 were mRNAs encoding the transmembrane receptor protein, TAPA-1, and the mitochondrial cytochrome c oxidase subunit II enzyme, coxII. A specific poly(C)-sensitive complex formed on the TAPA-1 and coxII 3' UTRs consistent with the binding of aCP1. Furthermore, direct binding of purified alphaCP proteins to these 3' UTRs was demonstrated and the binding sites determined. These results support the feasibility of the SNAAP technique and suggest a broad applicability for the approach in identifying mRNA targets for clinically relevant RNA-binding proteins that will provide insights into their possible functions. (+info)

Role of transmembrane 4 superfamily (TM4SF) proteins CD9 and CD81 in muscle cell fusion and myotube maintenance. (5/333)

The role of transmembrane 4 superfamily (TM4SF) proteins during muscle cell fusion has not been investigated previously. Here we show that the appearance of TM4SF protein, CD9, and the formation of CD9-beta1 integrin complexes were both regulated in coordination with murine C2C12 myoblast cell differentiation. Also, anti-CD9 and anti-CD81 monoclonal antibodies substantially inhibited and delayed conversion of C2C12 cells to elongated myotubes, without affecting muscle-specific protein expression. Studies of the human myoblast-derived RD sarcoma cell line further demonstrated that TM4SF proteins have a role during muscle cell fusion. Ectopic expression of CD9 caused a four- to eightfold increase in RD cell syncytia formation, whereas anti-CD9 and anti-CD81 antibodies markedly delayed RD syncytia formation. Finally, anti-CD9 and anti-CD81 monoclonal antibodies triggered apoptotic degeneration of C2C12 cell myotubes after they were formed. In summary, TM4SF proteins such as CD9 and CD81 appear to promote muscle cell fusion and support myotube maintenance. (+info)

Rapid and systemic accumulation of chloroplast mRNA-binding protein transcripts after flame stimulus in tomato. (6/333)

It has been shown that tomato (Lycopersicon esculentum) plants respond to flame wounding and electrical stimulation by a rapid (15 min) and systemic up-regulation of proteinase inhibitor (pin) genes. To find other genes having a similar expression pattern, we used subtractive cDNA screening between flamed and control plants to select clones up-regulated by flame wounding. We report the characterization of one of them, a chloroplast mRNA-binding protein encoded by a single gene and expressed preferentially in the leaves. Systemic gene expression in response to flaming in the youngest terminal leaf exhibited three distinct phases: a rapid and transient increase (5-15 min) in transcript accumulation, a decline to basal levels (15-45 min), and then a second, more prolonged increase (60-90 min). In contrast, after a mechanical wound the rapid, transient increase (5 min) was followed by a rapid decline to basal levels but no later, prolonged accumulation. In the petiole, the initial flame-wound-evoked transient increase (15 min) was followed by a continuous decline for 3 h. The nature of the wound signal(s) causing such rapid changes in transcript abundance is discussed in relation to electrical signaling, which has recently been implicated in plant responses to wounding. (+info)

Association of a tetraspanin CD9 with CD5 on the T cell surface: role of particular transmembrane domains in the association. (7/333)

CD9 is a member of the tetraspanin superfamily which is characterized by four transmembrane (TM) domains and associates with other surface molecules. This tetraspanin was recently found to be expressed on mature T cells. Here, we investigated which molecules associate with CD9 on T cells and which CD9 domains are required for the association. Immunoprecipitation of T cell lysates with anti-CD9 mAb followed by immunoblotting with mAb against various T cell molecules showed the association of CD9 with CD3, CD4, CD5, CD2, CD29 and CD44. Because association with CD5 was most prominent, we determined the role of CD9 TM or extracellular (EC) domains in the association with CD5. CD9 mutant genes lacking each domain were constructed and introduced into EL4 thymoma cells deficient in CD9 but expressing CD5. Among various types of stable EL4 transfectants, EL4 transfected with the mutant gene lacking TM domains (TM2/TM3) between two EC domains expressed a small amount of the relevant protein without showing association with CD5. CD9(-)CD5(-) monkey COS-7 cells transfected with this mutant gene and the CD5 gene expressed both transfected gene products, but the association of these was not detected. EL4 cells transfected with a CD9/CD81 chimera gene (the CD9 gene containing TM2/TM3 of CD81) expressed the chimeric protein on the cell surface and showed association with CD5. These results suggest an essential role of particular CD9 TM domains in the surface expression of the CD9 molecule as well as the association with CD5. (+info)

Functional characterization of intracellular and secreted forms of a truncated hepatitis C virus E2 glycoprotein. (8/333)

The E2 protein of hepatitis C virus (HCV) is believed to be a virion surface glycoprotein that is a candidate for inclusion in an antiviral vaccine. A truncated soluble version of E2 has recently been shown to interact with CD81, suggesting that this protein may be a component of the receptor for HCV. When expressed in eukaryotic cells, a significant proportion of E2 forms misfolded aggregates. To analyze the specificity of interaction between E2 and CD81, the aggregated and monomeric forms of a truncated E2 glycoprotein (E2(661)) were separated by high-pressure liquid chromatography and analyzed for CD81 binding. Nonaggregated forms of E2 preferentially bound CD81 and a number of conformation-dependent monoclonal antibodies (MAbs). Furthermore, intracellular forms of E2(661) were found to bind CD81 with greater affinity than the extracellular forms. Intracellular and secreted forms of E2(661) were also found to differ in reactivity with MAbs and human sera, consistent with differences in antigenicity. Together, these data indicate that proper folding of E2 is important for its interaction with CD81 and that modifications of glycans can modulate this interaction. Identification of the biologically active forms of E2 will assist in the future design of vaccines to protect against HCV infection. (+info)

No data available that match "antigens cd81"

CD81 (CD81 Molecule) is a Protein Coding gene. (genecards.org)
In our study, we combined single-molecule microscopy and biochemistry experiments to investigate the clustering and membrane behaviour of CD81 in the context of cells expressing EWI-2wint, a natural inhibitor of HCV entry. (nih.gov)
CD81 (TAPA-1): a molecule involved in signal transduction and cell adhesion in the immune system. (nih.gov)
Collectively the results obtained with this new structural model of E2c suggest the development of small molecule inhibitors such as 281816 that target E2 and disrupt its interaction with CD81 may provide a new paradigm for HCV treatment. (nih.gov)
CD81 molecule, also known as CD81 (Cluster of Differentiation 81), is a protein which in humans is encoded by the CD81 gene. (wikipedia.org)
Cell-surface expression of one or all of the candidate receptor molecules (CD81, low-density lipoprotein receptor, scavenger receptor class B type 1, and dendritic cell-specific intercellular adhesion molecule 3 grabbing nonintegrin) failed to confer permissivity to HIV-HCV pseudotype infection. (pnas.org)
Truncated soluble versions of E2 have been reported to bind specifically to human cells and were used to identify interactions with CD81 ( 7 , 8 ), scavenger receptor class B type 1 (SR-B1) ( 12 ), and dendritic cell-specific intercellular adhesion molecule 3 grabbing nonintegrin (DC-SIGN) ( 13 , 14 ). (pnas.org)
Today, the HLDA Workshop meeting has been held 10 times and has over 371 CD antigens molecule have been identified. (sinobiological.com)
CD81 is a widely expressed and evolutionary conserved molecule that associates with different proteins in different cell types ( ref/abstract ). (stanford.edu)
CD81 is required for normal immune responses, lack of this molecule results in weaker early antibody responses to protein antigens, specifically Th2 responses ( ref/abstract ). (stanford.edu)
CD81 is required for the normal expression of the CD19 signaling molecule in B cells ( ref/abstract ). (stanford.edu)
CD81 is also critical for infection of human hepatocytes by Plasmodium falciparum sporozoites, highlighting the importance of this molecule in the most widespread infectious disease known to mankind ( ref/abstract ). (stanford.edu)
The short antigen peptide is complexed to MHC class II molecule. (yourarticlelibrary.com)

The quality of each exosome preparation was confirmed by hybridization with antihuman leukocyte antigen (HLA) antibodies. (nih.gov)
Human peripheral blood mononuclear cells (PBMCs) were stained with CD81 antibodies or with the corresponding REA Control (S) antibodies (left images). (miltenyibiotec.com)
Now Offering Over 102,157 Antibodies & 44,722 Antigens! (avivasysbio.com)
Numerous antibodies have been described that potently neutralize a broad range of hepatitis C virus (HCV) isolates and the majority of these antibodies target the binding site for the cellular receptor CD81 within the major HCV glycoprotein E2. (frontiersin.org)
One of the most striking findings from these studies is that the same segments of the E2 polypeptide chain induce antibodies targeting distinct antigen conformations. (frontiersin.org)
The observation, by Ray Owen and colleagues in 1954, that D-negative women were less likely to form anti-D antibodies against their D-positive fetus if their mother possessed the D-antigen, was not found in all later studies. (haematologica.org)
For mismatched red blood cell antigens the mother was exposed to, whether or not antibodies were formed, we determined whether her mother, the grandmother, carried these antigens. (haematologica.org)
Maternal antibodies against IPAs expressed on red blood cells (RBC) such as Rh and K antigens, can cause severe hemolytic disease of the fetus and newborn (HDFN). (haematologica.org)
The expression of both CD19 and CD81 was determined with 3 different monoclonal antibodies. (jci.org)
Imai T, Yoshie O: C33 antigen and M38 antigen recognized by monoclonal antibodies inhibitory to syncytium formation by human T cell leukemia virus type 1 are both members of the transmembrane 4 superfamily and associate with each other and with CD4 or CD8 in T cells. (exbio.cz)
Fukudome K, Furuse M, Imai T, Nishimura M, Takagi S, Hinuma Y, Yoshie O: Identification of membrane antigen C33 recognized by monoclonal antibodies inhibitory to human T-cell leukemia virus type 1 (HTLV-1)-induced syncytium formation: altered glycosylation of C33 antigen in HTLV-1-positive T cells. (exbio.cz)
Anti-CD81 antibodies downregulate HIV production 3 fold, however the CD81 protein free virus is more infectious. (wikipedia.org)
See our complete line of Immunohistochemistry Reagents including antigen retrieval solutions, blocking agents ABC Detection Kits and polymers, biotinylated secondary antibodies, substrates and more. (lsbio.com)
Conserved epitopes like the viral CD81-binding site are targeted by rare broadly neutralizing antibodies. (uni-koeln.de)
Results: Mutant viruses bound soluble CD81 and antibodies targeting the CD81 binding site with enhanced efficacy. (uni-koeln.de)
The virus-containing vacuoles were also labeled with antibodies against LAMP-1, CD81, and CD82, which were also incorporated into the viral envelope. (rupress.org)
Only antibodies against antigens found in late endosomes precipitated infectious virus, whereas antibodies against proteins located primarily on the cell surface did not. (rupress.org)
AP33-related anti-idiotypes (Ab₂s) have the potential to carry the internal image of the antigen E2, eliciting the production of AP33-like antibodies in humans. (bl.uk)
We have so far established high quality monoclonal antibodies against human CD9, CD63 and CD81, which are members of tetraspanin superfamily and utilized as exosomal surface markers. (cosmobio.co.jp)
Moreover, the combination of these antibodies with one against a cancer cell surface antigen resulted in sensitive detection of cancer cell derived exosomes. (cosmobio.co.jp)
CD antigens for cluster of differentiation, which indicates a defined subset of cellular surface receptors (epitopes) that identify cell type and stage of differentiation, and which are recognized by antibodies. (sinobiological.com)

23499492 ). Upon initial encounter with a microbial pathogen, enables the assembly of CD19-CR2 and B cell receptor complexes at signaling TERMs, lowering the threshold dose of antigen required to trigger B cell clonal expansion and humoral immune response (By similarity). (uniprot.org)
Associates with CLDN1 and the CLDN1-CD81 receptor complex is essential for HCV entry into host cell. (nih.gov)
CD81 is a major receptor for Hepatitis C Virus (HCV). (nih.gov)
In addition, we showed that EWI-2wint influences the colocalization of CD81 with Claudin-1 - a co-receptor required for HCV entry. (nih.gov)
This unprecedented flexibility extends to the entire binding site for the cellular receptor CD81, underlining the importance of dynamic analyses to understand (1) the interplay between HCV and the humoral immune system and (2) the relevance of this structural flexibility for virus entry. (frontiersin.org)
In particular, the receptor-binding glycoprotein E2 contains major antigenic determinants of HCV, mostly overlapping with binding sites for cellular receptors, including scavenger receptor class B type 1 (SR-B1) ( 5 ), the low-density lipoprotein receptor (LDLr) ( 6 ), and the tetraspanin CD81 ( 7 ). (frontiersin.org)
B cells that respond are propagated and undergo a process called hypermutation, where their genes are rearranged to create a B cell receptor that better fits the foreign antigen. (news-medical.net)
B cells are activated when they bind to an antigen through a B cell receptor. (news-medical.net)
The surface receptor CD21 can enhance B cell activation in complex with CD19 and CD81. (news-medical.net)
In that process, the B cell receptor binds an antigen tagged with a fragment of C3 complement protein, and CD21 binds the fragment. (news-medical.net)
B cells can also undergo T cell dependent activation, which occurs when a B cell receptor binds a T cell-dependent antigen. (news-medical.net)
CD19 functions in a complex with CD21, CD81, and CD225 to signal with the B cell receptor upon antigen recognition. (jci.org)
Similar to CD19-deficient patients, CD81-deficient patients had B cells that showed impaired activation upon stimulation via the B cell antigen receptor but no overt T cell subset or function defects. (jci.org)
A first signal, which is antigen-specific, is provided through the T cell receptor (TCR) which interacts with peptide-MHC molecules on the membrane of antigen presenting cells (APC). (wikipedia.org)
HCV-E2 engaged CD81 is only 30% internalized after 12hr, suggesting CD81 may be primarily an attachment receptor for HCV. (wikipedia.org)
The CD8 antigen, acting as a coreceptor, and the T-cell receptor on the T lymphocyte recognize antigens displayed by an antigen presenting cell (APC) in the context of class I MHC molecules. (mybiosource.com)
Defects in the genes that encode for inducible costimulator (ICOS), transmembrane activator and CAML interactor (TACI), CD19, B-cell activating factor receptor (BAFFR), CD81, CD20, and CD21 have been reported [ 1 , 4 - 6 ]. (hindawi.com)
CD21 is the receptor for the C3 fraction of complement and is involved in signal transduction pathways triggered by the B cell receptor (BCR) with CD19 and CD81. (hindawi.com)
However, HIV-HCV pseudotype infectivity was inhibited by a recombinant soluble form of CD81 and a mAb specific for CD81, suggesting that CD81 may be a component of a receptor complex. (pnas.org)
CD81 has also been identified as en essential receptor for HCV (hepatitis C virus) (PMID: 21428934). (ptglab.com)
HCV-neutralizing antibody AP33 recognizes a linear, highly conserved epitope on the viral entry protein E2, disrupting the interaction with the cellular receptor CD81 that leads to viral entry. (bl.uk)
6] The presence of a transmembrane protein known as CD81 on the surface of these B cells may provide a pathway through which HCV can cause B-cell activation via the B-cell receptor. (cancernetwork.com)
For example, CD81 is a receptor for hepatitis C virus and for malarial parasites ( 11 , 41 ), and CD9 is a coreceptor for diphtheria toxin ( 21 ). (asm.org)
Low affinity receptor for IgE, ligand for CD19, CD21 and CD81. (sinobiological.com)
CD81 along with human scavenger receptor SR-BI, and tight junction molecules claudin-1 (CLDN) and occludin (OCLN) are the most important receptors that mediate HCV entry (46). (thefreedictionary.com)
The tetraspanin CD81 was originally identified in our laboratory as a receptor that controls cell growth. (stanford.edu)
CD81 is the putative receptor for HCV, CD81 is also required for infection by malaria. (stanford.edu)
My laboratory has been engaged in HCV related research since the identification of CD81 as the putative receptor of this virus. (stanford.edu)
Assembles with the antigen receptor of B-lymphocytes in order to decrease the threshold for antigen receptor-dependent stimulation. (cusabio.com)
Duffy antigen/chemokine receptor ( DARC ), also known as Fy glycoprotein ( FY ) or CD234 ( C luster of D ifferentiation 234), is a protein that in humans is encoded by the ACKR1 gene . (wikipedia.org)
CD81 has been also identified as a receptor for the hepatitis C virus. (sysmex-flowcytometry.com)
The sIg-antigen complex is internalized into the B cell by endocytosis (referred to as receptor-mediated or immuno- globulin-mediated endocytosis). (yourarticlelibrary.com)
1. The T cell receptor (TCR) of helper T cell binds to the MHC class II-antigen peptide complex on the B cell. (yourarticlelibrary.com)

CD81 (TAPA-1) is a widely expressed cell-surface protein involved in an astonishing variety of biologic responses. (nih.gov)
These mice do exhibit diminished antibody responses to protein antigens. (nih.gov)
Clone REA513 recognizes the human CD81 antigen, a multi-pass membrane protein also known as TAPA-1. (miltenyibiotec.com)
On the other hand, CD81 belongs to the tetraspanin family, which has been described as organizers of protein microdomains on the plasma membrane. (jimmunol.org)
EVs derived from antigen presenting cells (APCs) that are loaded with either peptide or whole protein antigens are reported to induce anti-tumor immunity in animal models but show only modest improvements in cancer patients ( 2 , 7 - 9 ). (frontiersin.org)
Recognizes CD81/ TAPA-1 antigen, a 23 kDa (smear) protein. (cellsciences.com)
The Eat-2 monoclonal antibody reacts with mouse CD81, a 26kDA non-glycosylated transmembrane protein. (peprotech.com)
The major HCV envelope protein E2 has been shown to bind to CD81. (pubmedcentralcanada.ca)
This Polyclonal antibody is directed against human CD81 protein. (lsbio.com)
CD81 (also known as TAPA1or TSPAN28) is a membrane protein of the tetraspanin superfamily, which are characterized by the presence of four conserved transmembrane regions. (ptglab.com)
Angelisova P, Vlcek C, Stefanova I, Lipoldova M, Horejsi V. The human leucocyte surface antigen CD53 is a protein structurally similar to the CD37 and MRC OX-44 antigens. (springer.com)
Q226 is involved in recognizing the CD8 protein, and the binding of CD8 to MHC class I is crucial to MHC class I's function in stimulating T lymphocytes to respond to foreign peptide antigens presented by MHC class I. Therefore I expect Q226 to be highly conserved. (proteopedia.org)
We mapped the critical amino acid of CD81 involved in binding the viral envelope protein. (stanford.edu)

HIV gag proteins use tetraspanin enriched microdomains (containing minimally CD81, CD82, CD63) as a platform for virion assembly and release. (wikipedia.org)
CD63 is a 53 kD type III lysosomal glycoprotein also known as LIMP, LAMP-3, gp55, and melanoma-associated antigen (ME491). (biolegend.com)
CD63 has been shown to associate with CD9, CD81, VLA-3, and VLA-6. (biolegend.com)
Here, we reveal the presence of tetraspanin-enriched microdomains (TEMs) containing the tetraspanins CD9, CD63, CD81, and CD82 at the plasma membrane. (rupress.org)
CD63 antigen is a member of the TM4 superfamily with its structure consisting of four transmembrane regions, short cytoplasmic N and C-termini and two extracellular regions. (leicabiosystems.com)
CD63 antigen is widely distributed on the surface and interior of both hematopoietic and non-hematopoietic cells such as most sweat glands, islets of Langerhans, pituitary, pancreas, peribronchial glands, Paneth cells and prostate glands. (leicabiosystems.com)
CD63 antigen associates non-covalently with CD9, CD81 and the integrins VLA-3, VLA-4 and VLA-6. (leicabiosystems.com)
It is reported that CD63 antigen may play a role as a tumor suppressor gene, as its expression in human melanoma cells reduces tumor spread and metastasis. (leicabiosystems.com)
Exosomes are 50-90 nm diameter vesicles containing antigen presenting molecules (MHC class I, class II, CD1, hsp70-90) tetraspan molecules (CD9, CD63, CD81), adhesion molecules (CD11b, CD54) and CD86 costimulatory molecules [ 17 - 19 ] i.e the necessary machinery required for generating potent immune responses. (biomedcentral.com)

Thus, association of HTLV-1 Gag with tetraspanin-enriched microdomains is mediated by the inner loops of CD81 and CD82. (nih.gov)
Imai T, Kakizaki M, Nishimura M, Yoshie O: Molecular analyses of the association of CD4 with two members of the transmembrane 4 superfamily, CD81 and CD82. (exbio.cz)
Some are involved in oncogenesis and in the control of metastasis: CD9, CD81, CD82, C0/029, and CD151 can all modulate cancer cell motility both in vitro and in vivo (reviewed in references 5 and 49). (asm.org)

The following antibody was used in this experiment: CD81 Monoclonal Antibody (Eat2) from Thermo Fisher Scientific, catalog # MA1-80209, RRID AB_929499. (thermofisher.com)
The mouse monoclonal antibody recognizes human CD81, a member of the transmembrane 4/ tetraspanin family. (cellsciences.com)
CD81 cross-linking by monoclonal antibody (mAb) specific for CD81 or by immobilized E2 have been shown to result in costimulatory signals for human T cells. (pubmedcentralcanada.ca)
CD81 antibody LS-C742193 is an unconjugated mouse monoclonal antibody to CD81 from human, feline and rabbit. (lsbio.com)

In this study, we present what we believe to be the first antibody deficiency syndrome caused by a mutation in the CD81 gene and consequent disruption of the CD19 complex on B cells. (jci.org)
Summary: TEHRAN (FNA)- Researchers found that mutations in the CD81 gene are the genetic cause of antibody deficiency. (thefreedictionary.com)
The Duffy antigen gene was the fourth gene associated with the resistance after the genes responsible for sickle cell anaemia , thalassemia and glucose-6-phosphate dehydrogenase . (wikipedia.org)
[6] The gene was first localised to chromosome 1 in 1968, and was the first blood system antigen to be localised. (wikipedia.org)

The CD antigens / Cluster of differentiation nomenclature was established in the 1st International Workshop and Conference on Human Leukocyte Differentiation Antigens (HLDA), which was held in Paris in 1982. (sinobiological.com)
Brackman D, Lund-Johansen F, Aarskog D. Expression of leukocyte differentiation antigens during the differentiation of HL-60 cells induced by 1,25-dihydroxyvitamin D3: comparison with the maturation of normal monocytic and granulocytic bone marrow cells. (springer.com)
CD81 forms complexes with other tetraspanin proteins, integrins, coreceptors, MHC class I and II molecules, and influences adhesion, morphology, activation, proliferation and differentiation of B, T and other cells, e.g. in muscles CD81 promotes cell fusion and myotube maintenance. (sysmex-flowcytometry.com)

On B cells CD81 is part of a complex with CD21, CD19, and Leu13. (nih.gov)
Expression of CD21 forms a complex with CD19 and CD81 to form the B cell coreceptor and it can serve as antigen-presenting cells, secrete cytokines, and differentiate into plasma cells that produce and secrete immunoglobulins (Foote et al. (thefreedictionary.com)
B lenfositlerinin yuzeyinde B hucre almaci (reseptoru) ile birlikte CD19, CD21, CD81 ve CD225 gibi ko-reseptorler de bulunmaktadir (13). (thefreedictionary.com)
CD19 molekulu CD21, CD81 ve CD225 ile B hucre reseptor kompleksi olusturarak antijen baglanmasi sonrasi B hucre reseptor sinyallerini kuvvetlendirir. (thefreedictionary.com)
After the naive mature B lymphocyte contacts the immunogen through surface IgM and/or IgD [with or without the B-lymphocyte CD21 (CR2), CD19, CD81 coreceptor interaction], help must be supplied by T-helper 1 or 2 cells to class switch to IgG (affinity maturation takes place as well). (thefreedictionary.com)
CD81 play role as a member of CD19/CD21/Leu-13 signal transdiction complex. (acmbcb.org)

The patient's B cells lack CD19 and CD81 membrane expression. (jci.org)
CR2 on mature B cells forms a complex with CD19 and CD81. (wikipedia.org)

Together, our results indicate that a change in membrane partitioning of CD81 occurs in the presence of EWI-2wint. (nih.gov)
These data indicate that CD9 and CD81 have an important role in membrane fusion induced by HIV-1 envelope. (jimmunol.org)
The antigen is then taken up into the B cell and presented to T cells on the cell membrane. (news-medical.net)
Retroviral transduction and glycosylation experiments on EBV-transformed B cells from the patient revealed that CD19 membrane expression critically depended on CD81. (jci.org)
B ). The patient's lymphocytes also completely lack CD81 membrane expression. (jci.org)
A second signal, the co-stimulatory signal, is antigen nonspecific and is provided by the interaction between co-stimulatory molecules expressed on the membrane of APC and the T cell. (wikipedia.org)
B cell binds antigens with its BCR (a membrane-bound antibody), which transfers intracellular signals to the B cell as well as inducing the B cell to engulf the antigen, process it, and present it on the MHC II molecules. (wikipedia.org)
Tetraspanins form multimolecular complexes with each other and with other membrane proteins, including integrins, major histocompatibility complex antigens, signaling complexes, and cell-associated growth factors. (asm.org)
Deneka M, Pelchen-Matthews A, Byland R, Ruiz-Mateos E, Marsh M. In macrophages, HIV-1 assembles into an intracellular plasma membrane domain containing the tetraspanins CD81, CD9, and CD53. (springer.com)
CD81 is required for membrane reorganization during fertilization, cd81-/- eggs do not fuse with sperm, resulting in female infertility ( ref/abstract ). (stanford.edu)

Like CD81, several tetraspanins are involved in cell adhesion, motility, and metastasis, as well as cell activation and signal transduction. (nih.gov)
Tetraspanins CD9 and CD81 are molecular partners of trimeric FcsRI on human antigen-presenting cells. (thefreedictionary.com)

Anti-CD81 can activate integrin alpha 4 beta 1 (VLA-4) on B cells, facilitating their adhesion to tonsilar interfollicular stroma. (nih.gov)
Similarly, anti-CD81 can activate alpha L beta 2 (LFA-1) on human thymocytes. (nih.gov)
CD81 can also affect cognate B-T cell interactions because anti-CD81 increases IL-4 synthesis by T cells responding to antigen presented by B cells but not by monocytes. (nih.gov)
In addition, anti-CD81 Abs triggered its clustering in patches, where CD4 and CXCR4 were included. (jimmunol.org)

Rat anti Mouse CD8 antibody, clone YTS169.4 recognizes the murine CD8 cell surface antigen, expressed by a subset of T lymphocytes. (mybiosource.com)

This I-domain containing alpha integrin combines with the beta 2 chain (ITGB2) to form the integrin lymphocyte function-associated antigen-1 (LFA-1), which is expressed on all leukocytes. (cancerindex.org)

Human peripheral blood lymphocytes were stained with CD81 (clone 5A6) Pacific Blue™ (filled histogram) or mouse IgG1, κ isotype control Pacific Blue™ (open histogram). (biolegend.com)
1X10^6 human peripheral blood lymphocytes were surface stained with 5 ul CoraLite®488-conjugated Anti-Human CD81 (CL488-65195, Clone: 5A6) (green) or isotype control antibody (black). (ptglab.com)

Non peptide antigen presentation to T-cell receptors on NKT cells. (sinobiological.com)
The MHC class Il-antigen peptide complex is transported to the B cell surface and expressed on the surface of B cell. (yourarticlelibrary.com)
The MHC class II antigen peptide complex on B cell is presented to the T H cell. (yourarticlelibrary.com)

CD81 induces B cell adhesion via VLA-4 integrin and has been shown to play a role in early T cell development. (biolegend.com)

Angelisova P, Hilgert I, Horejsi V. Association of four antigens of the tetraspans family (CD37, CD53, TAPA-1, and R2/C33) with MHC class II glycoproteins. (springer.com)

CVID6 is a primary immunodeficiency characterized by antibody deficiency, hypogammaglobulinemia, recurrent bacterial infections and an inability to mount an antibody response to antigen. (abcam.com)

CD81 is a 26 kD non-glycosylated member of the tetraspanin superfamily (TM4SF), also known as TAPA-1 (target of an antiproliferative antibody). (biolegend.com)

The species-specific traits in CD9 and CD81 distribution during sperm maturation were compared between mice and humans. (antikoerper-online.de)

CD81 is a 26kD cell surface glycoprotein that is also known as TAPA-1. (thermofisher.com)
CD81 is a cell surface glycoprotein that is known to complex with integrins. (cellsciences.com)
The large extracellular loop of CD81 binds the hepatitis E2 glycoprotein dimer. (wikipedia.org)
The CD8 antigen is a cell surface glycoprotein found on most cytotoxic T lymphocytes that mediates efficient cell-cell interactions within the immune system. (mybiosource.com)
Cloning of the virus enabled the production of the recombinant envelope glycoprotein E2, which in turn, was shown to bind to human CD81. (stanford.edu)

CD81 interacts directly with immunoglobulin superfamily member 8 (IGSF8, CD316) and CD36. (wikipedia.org)
CD81 is a member of the transmembrane 4 superfamily, also known as the tetraspanin family. (lsbio.com)
Along with CLDN1, LDL-R, and the tetraspanin superfamily member CD81, SCARB1 has been reported to be an entry factor for the Hepatitis C virus. (fishersci.com)

A T helper cell activated with the same antigen recognizes and binds the antigen complex, triggering a cascade of signals. (news-medical.net)
Whereas, a resting B cell, which binds to the antigen through the B cell surface immunoglobulin (sigs) becomes activated. (yourarticlelibrary.com)
The antigen binds to sIgs on B cell and cross-links the sIgs. (yourarticlelibrary.com)

Tissue, cells or virus corresponding to Human CD81. (abcam.com)
CD81 is required for Plasmodium vivax sporozoite entry into human hepatocytes and for Plasmodium yoelii sporozoite entry into murine hepatocytes. (wikipedia.org)
CD81 antibody LS-B6373 is an unconjugated rabbit polyclonal antibody to human CD81. (lsbio.com)
CL488-65195 targets CD81 in FC applications and shows reactivity with Human samples. (ptglab.com)
Human Antibody Laboratories manufactures the human serum contain antigen or antibody reagents distributed by Genprice. (muzeumamonitow.pl)
The Human Serum Contain Antigen Or Antibody reagent is RUO (Research Use Only) to test human serum or cell culture lab samples. (muzeumamonitow.pl)
Description: Alpha Fetoprotein, Antigen Grade, Cancer antigen from Human Cord Serum, 1.0 mg/Vial. (muzeumamonitow.pl)
CD81 has been implicated in the pathogenesis of two major human diseases: hepatitis C virus (HCV) and malaria. (stanford.edu)
We determined the structural basis for the interactions of the viral envelope proteins with human CD81. (stanford.edu)

Given the aberrant expression of specific genes in a variety of cancer types, restricted in testis or selected in normal tissue, cancer-testis antigens (CTAs) have emerged as efficient specific tumor targets which spare normal tissue from incurring damage during treatment 3 . (nature.com)
These observations support the proposal that nano-sized EVs can be used as carriers to deliver soluble antigens in tumor models ( 10 ). (frontiersin.org)
CD antigens are used widely for research, immunotherary, tumor and drug target. (sinobiological.com)
Fifteen patients fullfilling the inclusion criteria (stage IIIB and IV, HLA-A1 + , or -B35 + and HLA-DPO4 + leukocyte phenotype, tumor expressing MAGE3 antigen) were enrolled from 2000 to 2002 and received four exosome vaccinations. (biomedcentral.com)

Interestingly, we found that EWI-2wint reduces the global diffusion of CD81 molecules due to a decrease of the diffusion rate of mobile CD81 molecules and an increase in the proportion of confined molecules. (nih.gov)
Computational docking of a diverse library of 1,715 small molecules to this model led to the identification of a set of 34 ligands predicted to bind near conserved amino acid residues involved in the HCV E2: CD81 interaction. (nih.gov)
Dendritic cells displaying co-stimulatory molecules while presenting antigen are able to activate T cells. (wikipedia.org)
In contrast, T cells that recognize antigen presented by a dendritic cell not displaying co-stimulatory molecules are generally driven to apoptosis, or may become unresponsive to future encounters with the antigen. (wikipedia.org)
Both in DC lysates and on the surface of living cells, I-A and I-E molecules engaged in lateral interactions not observed on other antigen-presenting cells such as B blasts. (semanticscholar.org)
The CD antigens are protocol used for the identification and investigation of cell surface molecules providing targets for immunophenotyping of cells. (sinobiological.com)
Antigen binding to sIgs on B cell also induces the B cell to express large number of class II molecules and B7 molecules on B cell surface. (yourarticlelibrary.com)

In T cells, associates with CD4 or CD8 coreceptors and defines the maturation state of antigen-induced synapses with B cells (By similarity). (uniprot.org)
In fetal thymic organ culture, mAb to CD81 block maturation of CD4-CD8- thymocytes, and expression of CD81 on CHO cells endows those cells with the ability to support T cell maturation. (nih.gov)
During the different steps of their maturation, B cells circulate between splenic follicles, lymph nodes, and bone marrow, until they undergo apoptosis or are activated by an antigen. (hindawi.com)
Plasmodium sporozoites mature in the liver to merozoites, the stage that infects red blood cells, this maturation step is CD81-dependent. (stanford.edu)

Mouse monoclonal to CD81.COB81 reacts with the CD81, a target for anti-proliferative antigen (TAPA-1) with 26 kDa MW, which ia a member of the TM4SF tetraspanin family. (acmbcb.org)

This study gives new insights on the mechanism by which HCV enters into its target cells, namely by exploiting the dynamic properties of CD81. (nih.gov)
Similarly on T cells CD81 associates with CD4 and CD8 and provides a costimulatory signal with CD3. (nih.gov)
However, CD81-deficient mice express normal numbers and subsets of T cells. (nih.gov)
In rodents CD81 is expressed at much higher levels on resting B cells than on T cells, although increased expression on T cells is found following activation. (thermofisher.com)
CD81 is expressed by epithelial and endothelial cells, T and B cells, as well as natural killer (NK) cells. (miltenyibiotec.com)
Accordingly, overexpression of CD81 and CD9 rendered cells less susceptible to Env-mediated syncytia formation. (jimmunol.org)
Mature B cells in the peripheral blood are tested for their ability to recognize foreign antigens. (news-medical.net)
Impaired CD19 expression and signaling, enhanced antibody response to type II T independent antigen and reduction of B-1 cells in CD81-deficient mice. (harvard.edu)
The antibody M38 reacts with CD81, a 25 kDa member of the tetraspanin family, expressed on majority of cells. (exbio.cz)
Co-stimulation is a secondary signal which immune cells rely on to activate an immune response in the presence of an antigen-presenting cell. (wikipedia.org)
The latter case induces recognition by antigen-specific Th2 cells or Tfh cells, leading to activation of the B cell through binding of TCR to the MHC-antigen complex. (wikipedia.org)
This additional binding makes the B cells 100- to 10,000-fold more sensitive to antigen. (wikipedia.org)
Purified HIV produced by MOLT\HIV cells contains CD81. (wikipedia.org)
Engagement of CD81 lowers the signaling threshold required to trigger T-Cell\CD3 mediated proviral DNA in CD4+ T cells. (wikipedia.org)
Thus, HCV binding to natural killer (NK) cells could result in the cross-linking of CD81. (pubmedcentralcanada.ca)
To explore this possibility, we investigated whether cross-linking CD81 on NK cells could alter NK cell function. (pubmedcentralcanada.ca)
In this study, we show that CD81 cross-linking via immobilized E2 or mAbs specific for CD81 inhibits not only non major histocompatibility complex-restricted cytotoxicity mediated by NK cells but also interferon (IFN)-γ production by NK cells after exposure to interleukin (IL)-2, IL-12, IL-15, or CD16 cross-linking. (pubmedcentralcanada.ca)
These results show that CD81 cross-linking mediates completely different signals in NK cells versus T cells. (pubmedcentralcanada.ca)
In this study, we have investigated whether cross-linking CD81 on NK cells can alter NK cell function. (pubmedcentralcanada.ca)
Upon activation by an antigen, B cells differentiate either into plasma cells [ 12 ] or into memory B cells. (hindawi.com)
Mast cell-derived IL-13 downregulates IL-12 production by skin dendritic cells to inhibit the TH1 cell response to cutaneous antigen exposure. (childrenshospital.org)
13 CD169 + macrophages directly present captured antigen to T cells or natural killer (NK) T cells 17 and are adept at transferring antigen to CD8α + DC and B cells. (bloodjournal.org)
The cDNA encoding the corresponding antigen was cloned from megakaryoblastic leukemia cells and shown to be a member of the transmembrane 4 or tetraspanin family ( 10 ). (asm.org)
Are there differences between laboratories that use of fail to use the CDC's guidelines to measure CD41 and CD81 T cells? (thefreedictionary.com)
Therefore, it is conceivable that antigen spreading initiated by the specific T cells and/or intervention of alternate effectors also elicited by mature DC [ 11 , 12 ] might account for this apparent discrepancy. (biomedcentral.com)
CD81 is broadly expressed on hemapoietic cells and enothelial and epithelial cells, but absent from erythrocytes and platelets as well as neutrophils. (acmbcb.org)
Anti-CD19-chimeric antigen receptors T cells synergistically exerted collaborative cytotoxicity against primary double-hit lymphoma cells with anti-CD38-chimeric antigen receptors T cells. (cusabio.com)
The Duffy antigen is located on the surface of red blood cells , and is named after the patient in whom it was discovered. (wikipedia.org)
CD81 (TAPA-1), a member of the tetraspanin family, is expressed on virtually all nucleated cells, but above all on germinal center B cells. (sysmex-flowcytometry.com)
The developing B cells capable of reacting with self-antigens are killed in the bone marrow. (yourarticlelibrary.com)
When the memory B cell happens to contact the similar antigen (which induced the production of memory B cells from an activated B cell), the memory B cell gets activated. (yourarticlelibrary.com)

The impairment in Th2 responses is physiologically important, as cd81 -/- mice do not develop allergen-induced airway hyper-reactivity ( ref/abstract ). (stanford.edu)

Exposure of the CD81-binding site and conserved epitopes was quantified by soluble CD81 and antibody interaction and neutralization assays. (uni-koeln.de)

We hypothesize that CD81 affects a multitude of cell functions because it is essential for the spatial orientation of its associated/partner proteins in membranes. (stanford.edu)

CD81 is also physically and functionally associated with several integrins. (nih.gov)

Co-stimulation is required in addition to the antigen-specific signal from their antigen receptors. (wikipedia.org)

13 , 17 CD169 + macrophages sample a wide variety of antigens and participate in generation of immunity to tumors and viruses but may also down-regulate immune responses to self-tissue. (bloodjournal.org)

Pattern of expression of tetraspanin antigen genes in Burkitt lymphoma cell lines. (springer.com)

CD81 enhances cognate T-B cell interactions and greatly augments intracellular activation pathways leading to Th2 polarization ( ref/abstract ). (stanford.edu)

also called antibody deficiency due to CD81 defect. (abcam.com)
These findings may contribute to unraveling the genetic basis of antibody deficiency syndromes and the nonredundant functions of CD81 in humans. (jci.org)

APRIL expression is upregulated in atopic dermatitis skin lesions and at sites of antigen driven allergic skin inflammation in mice. (childrenshospital.org)
Interestingly, CD169 −/− mice demonstrated an enhanced response to antigen-pulsed exosomes. (bloodjournal.org)
This is supported by experiments showing that hepatic CD81 expression is increased in Pcsk9 (KO) mice and PCSK9 downregulates CD81 independently of LDL-R. (thefreedictionary.com)
To better define the role of CD81 we created CD81-deficient mice. (stanford.edu)
To determine its role we generated CD81 knockout (cd81-/-) mice. (stanford.edu)
cd81 -/- mice are resistant to infection by Plasmodium yoelii sporozoites. (stanford.edu)

Anatomy29

Organisms10

Diseases3

Chemicals and Drugs157

Analytical, Diagnostic and Therapeutic Techniques and Equipment27

Phenomena and Processes31

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Health Care3

Selective tetraspan-integrin complexes (CD81/alpha4beta1, CD151/alpha3beta1, CD151/alpha6beta1) under conditions disrupting tetraspan interactions. (1/333)

Characterization of hepatitis C virus E2 glycoprotein interaction with a putative cellular receptor, CD81. (2/333)

Functional analysis of cell surface-expressed hepatitis C virus E2 glycoprotein. (3/333)

Finding the right RNA: identification of cellular mRNA substrates for RNA-binding proteins. (4/333)

Role of transmembrane 4 superfamily (TM4SF) proteins CD9 and CD81 in muscle cell fusion and myotube maintenance. (5/333)

Rapid and systemic accumulation of chloroplast mRNA-binding protein transcripts after flame stimulus in tomato. (6/333)

Association of a tetraspanin CD9 with CD5 on the T cell surface: role of particular transmembrane domains in the association. (7/333)

Functional characterization of intracellular and secreted forms of a truncated hepatitis C virus E2 glycoprotein. (8/333)

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Antigens

Antigens, CD

Antigens, CD8

Antigens, Neoplasm

Antigens, CD3

Antigens, Surface

Antigens, Bacterial

Antigens, CD38

Antigens, CD34

Antigens, CD19

Antigens, CD40

CD40 Ligand

Antigens, CD20

Antigens, Viral

Antigens, CD28

Antigens, CD44

Antigens, CD7

Antigens, CD14

Antigens, CD2

CD4-CD8 Ratio

Antigens, CD5

Antigens, Differentiation

CD4-Positive T-Lymphocytes

Antigens, CD1

Antibodies, Monoclonal

Antigens, CD56

Antigens, Differentiation, T-Lymphocyte

ADP-ribosyl Cyclase

Antigens, Differentiation, Myelomonocytic

Antigens, CD80

Antigens, CD53

Antigens, CD24

Antigens, CD13

Antigens, Protozoan

T-Lymphocytes

Antigens, CD86

Flow Cytometry

B-Lymphocytes

Antigens, Polyomavirus Transforming

Antigens, CD95

HLA Antigens

Antigens, Differentiation, B-Lymphocyte

Antigens, CD45

Immunophenotyping

NAD+ Nucleosidase

Antigens, Fungal

Molecular Sequence Data

H-2 Antigens

Sialic Acid Binding Ig-like Lectin 3

Antigens, Helminth

Receptors, Antigen, T-Cell

Antigens, CD18

Lymphocyte Activation

Antigens, CD30

Membrane Glycoproteins

CD8-Positive T-Lymphocytes

Epitopes

Antigens, CD9

Carcinoembryonic Antigen

HLA-DR Antigens

Antigens, CD15

Antigens, Viral, Tumor

Cell Line

Antigens, CD43

Antigens, CD36

Amino Acid Sequence

Antigens, CD11

Histocompatibility Antigens Class II

Histocompatibility Antigens

Antigens, CD59

Receptors, Antigen, B-Cell

Proliferating Cell Nuclear Antigen

Antigens, CD57

Antigens, CD70

Antigens, CD46

Lectins, C-Type

Antigens, CD58

Antigens, CD4

Antigens, CD47

Antigens, CD11b