Lymphocytes: 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.Lymphocyte Activation: 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.T-Lymphocytes: 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.T-Lymphocytes, Cytotoxic: 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.Lymphocyte Subsets: A classification of lymphocytes based on structurally or functionally different populations of cells.Lymphocyte Count: The number of LYMPHOCYTES per unit volume of BLOOD.B-Lymphocytes: 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.CD4-Positive T-Lymphocytes: 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.Cytotoxicity, Immunologic: 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.CD8-Positive T-Lymphocytes: 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.Cells, Cultured: 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.Spleen: An encapsulated lymphatic organ through which venous blood filters.T-Lymphocyte Subsets: A classification of T-lymphocytes, especially into helper/inducer, suppressor/effector, and cytotoxic subsets, based on structurally or functionally different populations of cells.Lymphocyte Culture Test, Mixed: Measure of histocompatibility at the HL-A locus. Peripheral blood lymphocytes from two individuals are mixed together in tissue culture for several days. Lymphocytes from incompatible individuals will stimulate each other to proliferate significantly (measured by tritiated thymidine uptake) whereas those from compatible individuals will not. In the one-way MLC test, the lymphocytes from one of the individuals are inactivated (usually by treatment with MITOMYCIN or radiation) thereby allowing only the untreated remaining population of cells to proliferate in response to foreign histocompatibility antigens.Interleukin-2: A soluble substance elaborated by antigen- or mitogen-stimulated T-LYMPHOCYTES which induces DNA synthesis in naive lymphocytes.Antigens, CD3: 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).Flow Cytometry: 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.Phytohemagglutinins: Mucoproteins isolated from the kidney bean (Phaseolus vulgaris); some of them are mitogenic to lymphocytes, others agglutinate all or certain types of erythrocytes or lymphocytes. They are used mainly in the study of immune mechanisms and in cell culture.Lymphocytes, Tumor-Infiltrating: Lymphocytes that show specificity for autologous tumor cells. Ex vivo isolation and culturing of TIL with interleukin-2, followed by reinfusion into the patient, is one form of adoptive immunotherapy of cancer.Mice, Inbred C57BLConcanavalin A: A MANNOSE/GLUCOSE binding lectin isolated from the jack bean (Canavalia ensiformis). It is a potent mitogen used to stimulate cell proliferation in lymphocytes, primarily T-lymphocyte, cultures.Antigens, CD: 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.Mice, Inbred BALB CAntigens, Differentiation, T-Lymphocyte: 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.Receptors, Antigen, T-Cell: 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.Leukocyte Count: The number of WHITE BLOOD CELLS per unit volume in venous BLOOD. A differential leukocyte count measures the relative numbers of the different types of white cells.Interferon-gamma: 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.Antibodies, Monoclonal: Antibodies produced by a single clone of cells.Immunity, Cellular: 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.Clone Cells: 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)Cytotoxicity Tests, Immunologic: The demonstration of the cytotoxic effect on a target cell of a lymphocyte, a mediator released by a sensitized lymphocyte, an antibody, or complement.Jurkat Cells: A CELL LINE derived from human T-CELL LEUKEMIA and used to determine the mechanism of differential susceptibility to anti-cancer drugs and radiation.Thymus Gland: 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.Lymphocyte Transfusion: The transfer of lymphocytes from a donor to a recipient or reinfusion to the donor.Lymph Nodes: They are oval or bean shaped bodies (1 - 30 mm in diameter) located along the lymphatic system.Antigens, Surface: 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.Immunophenotyping: 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.Lymphocyte Depletion: Immunosuppression by reduction of circulating lymphocytes or by T-cell depletion of bone marrow. The former may be accomplished in vivo by thoracic duct drainage or administration of antilymphocyte serum. The latter is performed ex vivo on bone marrow before its transplantation.Lymphocyte Cooperation: T-cell enhancement of the B-cell response to thymic-dependent antigens.Epitopes: Sites on an antigen that interact with specific antibodies.Mitogens: Substances that stimulate mitosis and lymphocyte transformation. They include not only substances associated with LECTINS, but also substances from streptococci (associated with streptolysin S) and from strains of alpha-toxin-producing staphylococci. (Stedman, 25th ed)Killer Cells, Natural: 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.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Rosette Formation: The in vitro formation of clusters consisting of a cell (usually a lymphocyte) surrounded by antigenic cells or antigen-bearing particles (usually erythrocytes, which may or may not be coated with antibody or antibody and complement). The rosette-forming cell may be an antibody-forming cell, a memory cell, a T-cell, a cell bearing surface cytophilic antibodies, or a monocyte possessing Fc receptors. Rosette formation can be used to identify specific populations of these cells.Molecular Sequence Data: 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.Cytokines: 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.Cell SeparationLymphocyte Function-Associated Antigen-1: An integrin heterodimer widely expressed on cells of hematopoietic origin. CD11A ANTIGEN comprises the alpha chain and the CD18 antigen (ANTIGENS, CD18) the beta chain. Lymphocyte function-associated antigen-1 is a major receptor of T-CELLS; B-CELLS; and GRANULOCYTES. It mediates the leukocyte adhesion reactions underlying cytolytic conjugate formation, helper T-cell interactions, and antibody-dependent killing by NATURAL KILLER CELLS and granulocytes. Intracellular adhesion molecule-1 has been defined as a ligand for lymphocyte function-associated antigen-1.T-Lymphocytes, Helper-Inducer: Subpopulation of CD4+ lymphocytes that cooperate with other lymphocytes (either T or B) to initiate a variety of immune functions. For example, helper-inducer T-cells cooperate with B-cells to produce antibodies to thymus-dependent antigens and with other subpopulations of T-cells to initiate a variety of cell-mediated immune functions.Antigens, CD4: 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.Immunologic Memory: 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.Receptors, Lymphocyte Homing: Cell surface glycoproteins on lymphocytes and other leukocytes that mediate adhesion to specialized blood vessels called high endothelial venules. Several different classes of lymphocyte homing receptors have been identified, and they appear to target different surface molecules (addressins) on high endothelial venules in different tissues. The adhesion plays a crucial role in the trafficking of lymphocytes.Antigens, CD45: 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.Epitopes, T-Lymphocyte: 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.Membrane Glycoproteins: Glycoproteins found on the membrane or surface of cells.HLA-A2 Antigen: A specific HLA-A surface antigen subtype. Members of this subtype contain alpha chains that are encoded by the HLA-A*02 allele family.Receptors, Antigen, T-Cell, alpha-beta: 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.CD4-CD8 Ratio: 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.Receptors, Interleukin-2: 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.Cell Division: The fission of a CELL. It includes CYTOKINESIS, when the CYTOPLASM of a cell is divided, and CELL NUCLEUS DIVISION.Antigens, Neoplasm: 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.T-Lymphocytes, Regulatory: 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.Receptors, Antigen, T-Cell, gamma-delta: T-cell receptors composed of CD3-associated gamma and delta polypeptide chains and expressed primarily in CD4-/CD8- T-cells. The receptors appear to be preferentially located in epithelial sites and probably play a role in the recognition of bacterial antigens. The T-cell receptor gamma/delta chains are separate and not related to the gamma and delta chains which are subunits of CD3 (see ANTIGENS, CD3).Dendritic Cells: 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).Mice, Inbred Strains: 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.Monocytes: 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.Antigens: Substances that are recognized by the immune system and induce an immune reaction.HIV-1: The type species of LENTIVIRUS and the etiologic agent of AIDS. It is characterized by its cytopathic effect and affinity for the T4-lymphocyte.Leukocytes, Mononuclear: Mature LYMPHOCYTES and MONOCYTES transported by the blood to the body's extravascular space. They are morphologically distinguishable from mature granulocytic leukocytes by their large, non-lobed nuclei and lack of coarse, heavily stained cytoplasmic granules.H-2 Antigens: The major group of transplantation antigens in the mouse.Antigens, CD8: 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.Amino Acid Sequence: 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.Histocompatibility Antigens Class I: 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.Perforin: A calcium-dependent pore-forming protein synthesized in cytolytic LYMPHOCYTES and sequestered in secretory granules. Upon immunological reaction between a cytolytic lymphocyte and a target cell, perforin is released at the plasma membrane and polymerizes into transmembrane tubules (forming pores) which lead to death of a target cell.Histocompatibility Antigens: 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.Macrophages: 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.)Antigen Presentation: The process by which antigen is presented to lymphocytes in a form they can recognize. This is performed by antigen presenting cells (APCs). Some antigens require processing before they can be recognized. Antigen processing consists of ingestion and partial digestion of the antigen by the APC, followed by presentation of fragments on the cell surface. (From Rosen et al., Dictionary of Immunology, 1989)CD4 Lymphocyte Count: The number of CD4-POSITIVE T-LYMPHOCYTES per unit volume of BLOOD. Determination requires the use of a fluorescence-activated flow cytometer.Antigen-Presenting Cells: 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.Lectins: Proteins that share the common characteristic of binding to carbohydrates. Some ANTIBODIES and carbohydrate-metabolizing proteins (ENZYMES) also bind to carbohydrates, however they are not considered lectins. PLANT LECTINS are carbohydrate-binding proteins that have been primarily identified by their hemagglutinating activity (HEMAGGLUTININS). However, a variety of lectins occur in animal species where they serve diverse array of functions through specific carbohydrate recognition.Antigens, CD28: 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.Apoptosis: One of the mechanisms by which CELL DEATH occurs (compare with NECROSIS and AUTOPHAGOCYTOSIS). Apoptosis is the mechanism responsible for the physiological deletion of cells and appears to be intrinsically programmed. It is characterized by distinctive morphologic changes in the nucleus and cytoplasm, chromatin cleavage at regularly spaced sites, and the endonucleolytic cleavage of genomic DNA; (DNA FRAGMENTATION); at internucleosomal sites. This mode of cell death serves as a balance to mitosis in regulating the size of animal tissues and in mediating pathologic processes associated with tumor growth.Lymphocytes, Null: A class of lymphocytes characterized by the lack of surface markers specific for either T or B lymphocytes.Immune Adherence Reaction: A method for the detection of very small quantities of antibody in which the antigen-antibody-complement complex adheres to indicator cells, usually primate erythrocytes or nonprimate blood platelets. The reaction is dependent on the number of bound C3 molecules on the C3b receptor sites of the indicator cell.Lymphoid Tissue: Specialized tissues that are components of the lymphatic system. They provide fixed locations within the body where a variety of LYMPHOCYTES can form, mature and multiply. The lymphoid tissues are connected by a network of LYMPHATIC VESSELS.Immunoglobulins: Multi-subunit proteins which function in IMMUNITY. They are produced by B LYMPHOCYTES from the IMMUNOGLOBULIN GENES. They are comprised of two heavy (IMMUNOGLOBULIN HEAVY CHAINS) and two light chains (IMMUNOGLOBULIN LIGHT CHAINS) with additional ancillary polypeptide chains depending on their isoforms. The variety of isoforms include monomeric or polymeric forms, and transmembrane forms (B-CELL ANTIGEN RECEPTORS) or secreted forms (ANTIBODIES). They are divided by the amino acid sequence of their heavy chains into five classes (IMMUNOGLOBULIN A; IMMUNOGLOBULIN D; IMMUNOGLOBULIN E; IMMUNOGLOBULIN G; IMMUNOGLOBULIN M) and various subclasses.Immunotherapy, Adoptive: Form of adoptive transfer where cells with antitumor activity are transferred to the tumor-bearing host in order to mediate tumor regression. The lymphoid cells commonly used are lymphokine-activated killer (LAK) cells and tumor-infiltrating lymphocytes (TIL). This is usually considered a form of passive immunotherapy. (From DeVita, et al., Cancer, 1993, pp.305-7, 314)Immune Tolerance: 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.Receptors, Antigen, B-Cell: 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.Mice, Knockout: Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.Pore Forming Cytotoxic Proteins: Proteins secreted from an organism which form membrane-spanning pores in target cells to destroy them. This is in contrast to PORINS and MEMBRANE TRANSPORT PROTEINS that function within the synthesizing organism and COMPLEMENT immune proteins. These pore forming cytotoxic proteins are a form of primitive cellular defense which are also found in human LYMPHOCYTES.Antibody Formation: The production of ANTIBODIES by proliferating and differentiated B-LYMPHOCYTES under stimulation by ANTIGENS.Cell Movement: The movement of cells from one location to another. Distinguish from CYTOKINESIS which is the process of dividing the CYTOPLASM of a cell.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Signal Transduction: 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.Granzymes: A family of serine endopeptidases found in the SECRETORY GRANULES of LEUKOCYTES such as CYTOTOXIC T-LYMPHOCYTES and NATURAL KILLER CELLS. When secreted into the intercellular space granzymes act to eliminate transformed and virus-infected host cells.Mice, Transgenic: Laboratory mice that have been produced from a genetically manipulated EGG or EMBRYO, MAMMALIAN.Leukemia, Lymphoid: Leukemia associated with HYPERPLASIA of the lymphoid tissues and increased numbers of circulating malignant LYMPHOCYTES and lymphoblasts.Cell Differentiation: Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.Interleukin-4: A soluble factor produced by activated T-LYMPHOCYTES that induces the expression of MHC CLASS II GENES and FC RECEPTORS on B-LYMPHOCYTES and causes their proliferation and differentiation. It also acts on T-lymphocytes, MAST CELLS, and several other hematopoietic lineage cells.RNA, Messenger: 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, CD95: 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.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Antigens, Differentiation: 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.Fas Ligand Protein: A transmembrane protein belonging to the tumor necrosis factor superfamily that was originally discovered on cells of the lymphoid-myeloid lineage, including activated T-LYMPHOCYTES and NATURAL KILLER CELLS. It plays an important role in immune homeostasis and cell-mediated toxicity by binding to the FAS RECEPTOR and triggering APOPTOSIS.HLA-DR Antigens: 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.Histocompatibility Antigens Class II: 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.Antigens, CD2: 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.Tumor Cells, Cultured: 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.Major Histocompatibility Complex: 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.Mice, Inbred C3HAntigens, Viral: Substances elaborated by viruses that have antigenic activity.Receptors, Immunologic: Cell surface molecules on cells of the immune system that specifically bind surface molecules or messenger molecules and trigger changes in the behavior of cells. Although these receptors were first identified in the immune system, many have important functions elsewhere.Immunoglobulin G: The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of IgG, for example, IgG1, IgG2A, and IgG2B.Palatine Tonsil: A round-to-oval mass of lymphoid tissue embedded in the lateral wall of the PHARYNX. There is one on each side of the oropharynx in the fauces between the anterior and posterior pillars of the SOFT PALATE.HLA-A Antigens: 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.Chemotaxis, Leukocyte: The movement of leukocytes in response to a chemical concentration gradient or to products formed in an immunologic reaction.Pokeweed Mitogens: Proteins isolated from the roots of the pokeweed, Phytolacca americana, that agglutinate some erythrocytes, stimulate mitosis and antibody synthesis in lymphocytes, and induce activation of plasma cells.Cell Adhesion: Adherence of cells to surfaces or to other cells.Dose-Response Relationship, Immunologic: A specific immune response elicited by a specific dose of an immunologically active substance or cell in an organism, tissue, or cell.HLA Antigens: 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.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Immunoglobulin M: 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.Immunization: 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).Mice, Inbred CBAHypersensitivity, Delayed: An increased reactivity to specific antigens mediated not by antibodies but by cells.Lymphopenia: Reduction in the number of lymphocytes.HIV Infections: Includes the spectrum of human immunodeficiency virus infections that range from asymptomatic seropositivity, thru AIDS-related complex (ARC), to acquired immunodeficiency syndrome (AIDS).Gene Expression Regulation: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.Fluorescent Antibody Technique: 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.Adoptive Transfer: 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).Coculture Techniques: A technique of culturing mixed cell types in vitro to allow their synergistic or antagonistic interactions, such as on CELL DIFFERENTIATION or APOPTOSIS. Coculture can be of different types of cells, tissues, or organs from normal or disease states.Immunologic Deficiency Syndromes: Syndromes in which there is a deficiency or defect in the mechanisms of immunity, either cellular or humoral.Leukocytes: White blood cells. These include granular leukocytes (BASOPHILS; EOSINOPHILS; and NEUTROPHILS) as well as non-granular leukocytes (LYMPHOCYTES and MONOCYTES).Immunotherapy: Manipulation of the host's immune system in treatment of disease. It includes both active and passive immunization as well as immunosuppressive therapy to prevent graft rejection.Herpesvirus 4, Human: 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.Lymphocyte Specific Protein Tyrosine Kinase p56(lck): This enzyme is a lymphoid-specific src family tyrosine kinase that is critical for T-cell development and activation. Lck is associated with the cytoplasmic domains of CD4, CD8 and the beta-chain of the IL-2 receptor, and is thought to be involved in the earliest steps of TCR-mediated T-cell activation.Immunosuppression: Deliberate prevention or diminution of the host's immune response. It may be nonspecific as in the administration of immunosuppressive agents (drugs or radiation) or by lymphocyte depletion or may be specific as in desensitization or the simultaneous administration of antigen and immunosuppressive drugs.ThymidineRecombinant Proteins: Proteins prepared by recombinant DNA technology.Cell Communication: Any of several ways in which living cells of an organism communicate with one another, whether by direct contact between cells or by means of chemical signals carried by neurotransmitter substances, hormones, and cyclic AMP.Tuberculin: A protein extracted from boiled culture of tubercle bacilli (MYCOBACTERIUM TUBERCULOSIS). It is used in the tuberculin skin test (TUBERCULIN TEST) for the diagnosis of tuberculosis infection in asymptomatic persons.Antilymphocyte Serum: Serum containing GAMMA-GLOBULINS which are antibodies for lymphocyte ANTIGENS. It is used both as a test for HISTOCOMPATIBILITY and therapeutically in TRANSPLANTATION.Cell Proliferation: All of the processes involved in increasing CELL NUMBER including CELL DIVISION.Autoimmune Diseases: Disorders that are characterized by the production of antibodies that react with host tissues or immune effector cells that are autoreactive to endogenous peptides.Mice, Inbred DBAThoracic Duct: The largest lymphatic vessel that passes through the chest and drains into the SUBCLAVIAN VEIN.L-Selectin: Cell adhesion molecule and CD antigen that serves as a homing receptor for lymphocytes to lymph node high endothelial venules.Cell Line, Transformed: Eukaryotic cell line obtained in a quiescent or stationary phase which undergoes conversion to a state of unregulated growth in culture, resembling an in vitro tumor. It occurs spontaneously or through interaction with viruses, oncogenes, radiation, or drugs/chemicals.Immunosuppressive Agents: Agents that suppress immune function by one of several mechanisms of action. Classical cytotoxic immunosuppressants act by inhibiting DNA synthesis. Others may act through activation of T-CELLS or by inhibiting the activation of HELPER CELLS. While immunosuppression has been brought about in the past primarily to prevent rejection of transplanted organs, new applications involving mediation of the effects of INTERLEUKINS and other CYTOKINES are emerging.DNA: A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).Peptide Fragments: Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.Melanoma: A malignant neoplasm derived from cells that are capable of forming melanin, which may occur in the skin of any part of the body, in the eye, or, rarely, in the mucous membranes of the genitalia, anus, oral cavity, or other sites. It occurs mostly in adults and may originate de novo or from a pigmented nevus or malignant lentigo. Melanomas frequently metastasize widely, and the regional lymph nodes, liver, lungs, and brain are likely to be involved. The incidence of malignant skin melanomas is rising rapidly in all parts of the world. (Stedman, 25th ed; from Rook et al., Textbook of Dermatology, 4th ed, p2445)Cell Adhesion Molecules: Surface ligands, usually glycoproteins, that mediate cell-to-cell adhesion. Their functions include the assembly and interconnection of various vertebrate systems, as well as maintenance of tissue integration, wound healing, morphogenic movements, cellular migrations, and metastasis.Th1 Cells: Subset of helper-inducer T-lymphocytes which synthesize and secrete interleukin-2, gamma-interferon, and interleukin-12. Due to their ability to kill antigen-presenting cells and their lymphokine-mediated effector activity, Th1 cells are associated with vigorous delayed-type hypersensitivity reactions.Tumor Necrosis Factor-alpha: Serum glycoprotein produced by activated MACROPHAGES and other mammalian MONONUCLEAR LEUKOCYTES. It has necrotizing activity against tumor cell lines and increases ability to reject tumor transplants. Also known as TNF-alpha, it is only 30% homologous to TNF-beta (LYMPHOTOXIN), but they share TNF RECEPTORS.CTLA-4 Antigen: 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.Gene Expression: The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.Peptides: 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.Rats, Inbred LewVirus Replication: The process of intracellular viral multiplication, consisting of the synthesis of PROTEINS; NUCLEIC ACIDS; and sometimes LIPIDS, and their assembly into a new infectious particle.Kinetics: The rate dynamics in chemical or physical systems.Receptor-CD3 Complex, Antigen, T-Cell: Molecule composed of the non-covalent association of the T-cell antigen receptor (RECEPTORS, ANTIGEN, T-CELL) with the CD3 complex (ANTIGENS, CD3). This association is required for the surface expression and function of both components. The molecule consists of up to seven chains: either the alpha/beta or gamma/delta chains of the T-cell receptor, and four or five chains in the CD3 complex.Immunization, Passive: Transfer of immunity from immunized to non-immune host by administration of serum antibodies, or transplantation of lymphocytes (ADOPTIVE TRANSFER).Transfection: 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.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Lymphoma: A general term for various neoplastic diseases of the lymphoid tissue.Graft vs Host Reaction: An immunological attack mounted by a graft against the host because of tissue incompatibility when immunologically competent cells are transplanted to an immunologically incompetent host; the resulting clinical picture is that of GRAFT VS HOST DISEASE.Antibodies: 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).Adjuvants, Immunologic: 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.Transplantation, Homologous: Transplantation between individuals of the same species. Usually refers to genetically disparate individuals in contradistinction to isogeneic transplantation for genetically identical individuals.Muromonab-CD3: Anti-CD3 monoclonal antibody that exerts immunosuppressive effects by inducing peripheral T-cell depletion and modulation of the T-cell receptor complex (CD3/Ti).Receptors, Chemokine: Cell surface glycoproteins that bind to chemokines and thus mediate the migration of pro-inflammatory molecules. The receptors are members of the seven-transmembrane G protein-coupled receptor family. Like the CHEMOKINES themselves, the receptors can be divided into at least three structural branches: CR, CCR, and CXCR, according to variations in a shared cysteine motif.Cell Survival: The span of viability of a cell characterized by the capacity to perform certain functions such as metabolism, growth, reproduction, some form of responsiveness, and adaptability.Intestinal Mucosa: Lining of the INTESTINES, consisting of an inner EPITHELIUM, a middle LAMINA PROPRIA, and an outer MUSCULARIS MUCOSAE. In the SMALL INTESTINE, the mucosa is characterized by a series of folds and abundance of absorptive cells (ENTEROCYTES) with MICROVILLI.Mice, SCID: 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.Membrane Proteins: Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Immunologic Capping: An energy dependent process following the crosslinking of B CELL ANTIGEN RECEPTORS by multivalent ligands (bivalent anti-antibodies, LECTINS or ANTIGENS), on the B-cell surface. The crosslinked ligand-antigen receptor complexes collect in patches which flow to and aggregate at one pole of the cell to form a large mass - the cap. The caps may then be endocytosed or shed into the environment.Thymectomy: Surgical removal of the thymus gland. (Dorland, 28th ed)Immunoconjugates: Combinations of diagnostic or therapeutic substances linked with specific immune substances such as IMMUNOGLOBULINS; MONOCLONAL ANTIBODIES; or ANTIGENS. Often the diagnostic or therapeutic substance is a radionuclide. These conjugates are useful tools for specific targeting of DRUGS and RADIOISOTOPES in the CHEMOTHERAPY and RADIOIMMUNOTHERAPY of certain cancers.Lymphokines: Soluble protein factors generated by activated lymphocytes that affect other cells, primarily those involved in cellular immunity.Lectins, C-Type: 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.Bone Marrow Cells: Cells contained in the bone marrow including fat cells (see ADIPOCYTES); STROMAL CELLS; MEGAKARYOCYTES; and the immediate precursors of most blood cells.Polymerase Chain Reaction: In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.Enzyme-Linked Immunosorbent Assay: 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.B-Lymphocyte Subsets: A classification of B-lymphocytes based on structurally or functionally different populations of cells.Receptors, Fc: Molecules found on the surface of some, but not all, B-lymphocytes, T-lymphocytes, and macrophages, which recognize and combine with the Fc (crystallizable) portion of immunoglobulin molecules.Th2 Cells: Subset of helper-inducer T-lymphocytes which synthesize and secrete the interleukins IL-4, IL-5, IL-6, and IL-10. These cytokines influence B-cell development and antibody production as well as augmenting humoral responses.Models, Immunological: Theoretical representations that simulate the behavior or activity of immune system, processes, or phenomena. They include the use of mathematical equations, computers, and other electrical equipment.Disease Models, Animal: Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.Up-Regulation: A positive regulatory effect on physiological processes at the molecular, cellular, or systemic level. At the molecular level, the major regulatory sites include membrane receptors, genes (GENE EXPRESSION REGULATION), mRNAs (RNA, MESSENGER), and proteins.Chromium Radioisotopes: Unstable isotopes of chromium that decay or disintegrate emitting radiation. Cr atoms with atomic weights of 46-49, 51, 55, and 56 are radioactive chromium isotopes.Antigen-Antibody Reactions: The processes triggered by interactions of ANTIBODIES with their ANTIGENS.Bone Marrow: 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.Macaca mulatta: A species of the genus MACACA inhabiting India, China, and other parts of Asia. The species is used extensively in biomedical research and adapts very well to living with humans.Ovalbumin: An albumin obtained from the white of eggs. It is a member of the serpin superfamily.Genetic Vectors: DNA molecules capable of autonomous replication within a host cell and into which other DNA sequences can be inserted and thus amplified. Many are derived from PLASMIDS; BACTERIOPHAGES; or VIRUSES. They are used for transporting foreign genes into recipient cells. Genetic vectors possess a functional replicator site and contain GENETIC MARKERS to facilitate their selective recognition.Simian immunodeficiency virus: Species of the genus LENTIVIRUS, subgenus primate immunodeficiency viruses (IMMUNODEFICIENCY VIRUSES, PRIMATE), that induces acquired immunodeficiency syndrome in monkeys and apes (SAIDS). The genetic organization of SIV is virtually identical to HIV.Ionomycin: A divalent calcium ionophore that is widely used as a tool to investigate the role of intracellular calcium in cellular processes.Antibody-Producing Cells: Cells of the lymphoid series that can react with antigen to produce specific cell products called antibodies. Various cell subpopulations, often B-lymphocytes, can be defined, based on the different classes of immunoglobulins that they synthesize.

T-cell development: a new marker of differentiation state. (1/39207)

Differentiation of T cells is a complicated affair and there has been a dearth of markers that faithfully reflect thymocyte phenotype. A new strategy based on T-cell receptor gene sequencing has revealed a marker that can be used to monitor thymocyte differentiation with fidelity and without perturbation.  (+info)

The hematopoietic-specific adaptor protein gads functions in T-cell signaling via interactions with the SLP-76 and LAT adaptors. (2/39207)

BACKGROUND: The adaptor protein Gads is a Grb2-related protein originally identified on the basis of its interaction with the tyrosine-phosphorylated form of the docking protein Shc. Gads protein expression is restricted to hematopoietic tissues and cell lines. Gads contains a Src homology 2 (SH2) domain, which has previously been shown to have a similar binding specificity to that of Grb2. Gads also possesses two SH3 domains, but these have a distinct binding specificity to those of Grb2, as Gads does not bind to known Grb2 SH3 domain targets. Here, we investigated whether Gads is involved in T-cell signaling. RESULTS: We found that Gads is highly expressed in T cells and that the SLP-76 adaptor protein is a major Gads-associated protein in vivo. The constitutive interaction between Gads and SLP-76 was mediated by the carboxy-terminal SH3 domain of Gads and a 20 amino-acid proline-rich region in SLP-76. Gads also coimmunoprecipitated the tyrosine-phosphorylated form of the linker for activated T cells (LAT) adaptor protein following cross-linking of the T-cell receptor; this interaction was mediated by the Gads SH2 domain. Overexpression of Gads and SLP-76 resulted in a synergistic augmentation of T-cell signaling, as measured by activation of nuclear factor of activated T cells (NFAT), and this cooperation required a functional Gads SH2 domain. CONCLUSIONS: These results demonstrate that Gads plays an important role in T-cell signaling via its association with SLP-76 and LAT. Gads may promote cross-talk between the LAT and SLP-76 signaling complexes, thereby coupling membrane-proximal events to downstream signaling pathways.  (+info)

JNK2 is required for efficient T-cell activation and apoptosis but not for normal lymphocyte development. (3/39207)

BACKGROUND: The Jun N-terminal kinase (JNK) signaling pathway has been implicated in cell proliferation and apoptosis, but its function seems to depend on the cell type and inducing signal. In T cells, JNK has been implicated in both antigen-induced activation and apoptosis. RESULTS: We generated mice lacking the JNK2 isozymes. The mutant mice were healthy and fertile but defective in peripheral T-cell activation induced by antibody to the CD3 component of the T-cell receptor (TCR) complex - proliferation and production of interleukin-2 (IL-2), IL-4 and interferon-gamma (IFN-gamma) were reduced. The proliferation defect was restored by exogenous IL-2. B-cell activation was normal in the absence of JNK2. Activation-induced peripheral T-cell apoptosis was comparable between mutant and wild-type mice, but immature (CD4(+) CD8(+)) thymocytes lacking JNK2 were resistant to apoptosis induced by administration of anti-CD3 antibody in vivo. The lack of JNK2 also resulted in partial resistance of thymocytes to anti-CD3 antibody in vitro, but had little or no effect on apoptosis induced by anti-Fas antibody, dexamethasone or ultraviolet-C (UVC) radiation. CONCLUSIONS: JNK2 is essential for efficient activation of peripheral T cells but not B cells. Peripheral T-cell activation is probably required indirectly for induction of thymocyte apoptosis resulting from administration of anti-CD3 antibody in vivo. JNK2 functions in a cell-type-specific and stimulus-dependent manner, being required for apoptosis of immature thymocytes induced by anti-CD3 antibody but not for apoptosis induced by anti-Fas antibody, UVC or dexamethasone. JNK2 is not required for activation-induced cell death of mature T cells.  (+info)

Hematopoietic stem-cell transplantation for the treatment of severe combined immunodeficiency. (4/39207)

BACKGROUND: Since 1968 it has been known that bone marrow transplantation can ameliorate severe combined immunodeficiency, but data on the long-term efficacy of this treatment are limited. We prospectively studied immunologic function in 89 consecutive infants with severe combined immunodeficiency who received hematopoietic stem-cell transplants at Duke University Medical Center between May 1982 and September 1998. METHODS: Serum immunoglobulin levels and lymphocyte phenotypes and function were assessed and genetic analyses performed according to standard methods. Bone marrow was depleted of T cells by agglutination with soybean lectin and by sheep-erythrocyte rosetting before transplantation. RESULTS: Seventy-seven of the infants received T-cell-depleted, HLA-haploidentical parental marrow, and 12 received HLA-identical marrow from a related donor; 3 of the recipients of haploidentical marrow also received placental-blood transplants from unrelated donors. Except for two patients who received placental blood, none of the recipients received chemotherapy before transplantation or prophylaxis against graft-versus-host disease. Of the 89 infants, 72 (81 percent) were still alive 3 months to 16.5 years after transplantation, including all of the 12 who received HLA-identical marrow, 60 of the 77 (78 percent) who were given haploidentical marrow, and 2 of the 3 (67 percent) who received both haploidentical marrow and placental blood. T-cell function became normal within two weeks after transplantation in the patients who received unfractionated HLA-identical marrow but usually not until three to four months after transplantation in those who received T-cell-depleted marrow. At the time of the most recent evaluation, all but 4 of the 72 survivors had normal T-cell function, and all the T cells in their blood were of donor origin. B-cell function remained abnormal in many of the recipients of haploidentical marrow. In 26 children (5 recipients of HLA-identical marrow and 21 recipients of haploidentical marrow) between 2 percent and 100 percent of B cells were of donor origin. Forty-five of the 72 children were receiving intravenous immune globulin. CONCLUSIONS: Transplantation of marrow from a related donor is a life-saving and life-sustaining treatment for patients with any type of severe combined immunodeficiency, even when there is no HLA-identical donor.  (+info)

Tyrosine phosphorylation and complex formation of Cbl-b upon T cell receptor stimulation. (5/39207)

Cbl-b, a mammalian homolog of Cbl, consists of an N-terminal region (Cbl-b-N) highly homologous to oncogenic v-Cbl, a Ring finger, and a C-terminal region containing multiple proline-rich stretches and potential tyrosine phosphorylation sites. In the present study, we demonstrate that upon engagement of the T cell receptor (TCR), endogenous Cbl-b becomes rapidly tyrosine-phosphorylated. In heterogeneous COS-1 cells, Cbl-b was phosphorylated on tyrosine residues by both Syk- (Syk/Zap-70) and Src- (Fyn/Lck) family kinases, with Syk kinase inducing the most prominent effect. Syk associates and phosphorylates Cbl-b in Jurkat T cells. A Tyr-316 Cbl-binding site in Syk was required for the association with and for the maximal tyrosine phosphorylation of Cbl-b. Mutation at a loss-of-function site (Gly-298) in Cbl-b-N disrupts its interaction with Syk. Cbl-b constitutively binds Grb2 and becomes associated with Crk-L upon TCR stimulation. The Grb2- and the Crk-L-binding regions were mapped to the C-terminus of Cbl-b. The Crk-L-binding sites were further determined to be Y655DVP and Y709KIP, with the latter being the primary binding site. Taken together, these results implicate that Cbl-b is involved in TCR-mediated intracellular signaling pathways.  (+info)

Vascular endothelial growth factor activates nuclear factor of activated T cells in human endothelial cells: a role for tissue factor gene expression. (6/39207)

Vascular endothelial growth factor (VEGF) is a potent angiogenic inducer that stimulates the expression of tissue factor (TF), the major cellular initiator of blood coagulation. Here we show that signaling triggered by VEGF induced DNA-binding and transcriptional activities of nuclear factor of activated T cells (NFAT) and AP-1 in human umbilical vein endothelial cells (HUVECs). VEGF also induced TF mRNA expression and gene promoter activation by a cyclosporin A (CsA)-sensitive mechanism. As in lymphoid cells, NFAT was dephosphorylated and translocated to the nucleus upon activation of HUVECs, and these processes were blocked by CsA. NFAT was involved in the VEGF-mediated TF promoter activation as evidenced by cotransfection experiments with a dominant negative version of NFAT and site-directed mutagenesis of a newly identified NFAT site within the TF promoter that overlaps with a previously identified kappaB-like site. Strikingly, this site bound exclusively NFAT not only from nuclear extracts of HUVECs activated by VEGF, a stimulus that failed to induce NF-kappaB-binding activity, but also from extracts of cells activated with phorbol esters and calcium ionophore, a combination of stimuli that triggered the simultaneous activation of NFAT and NF-kappaB. These results implicate NFAT in the regulation of endothelial genes by physiological means and shed light on the mechanisms that switch on the gene expression program induced by VEGF and those regulating TF gene expression.  (+info)

Activation-dependent transcriptional regulation of the human Fas promoter requires NF-kappaB p50-p65 recruitment. (7/39207)

Fas (CD95) and Fas ligand (CD95L) are an interacting receptor-ligand pair required for immune homeostasis. Lymphocyte activation results in the upregulation of Fas expression and the acquisition of sensitivity to FasL-mediated apoptosis. Although Fas upregulation is central to the preservation of immunologic tolerance, little is known about the molecular machinery underlying this process. To investigate the events involved in activation-induced Fas upregulation, we have examined mRNA accumulation, fas promoter activity, and protein expression in the Jurkat T-cell line treated with phorbol myristate acetate and ionomycin (P/I), pharmacological mimics of T-cell receptor activation. Although resting Jurkat cells express Fas, Fas mRNA was induced approximately 10-fold in 2 h upon P/I stimulation. Using sequential deletion mutants of the human fas promoter in transient transfection assays, we identified a 47-bp sequence (positions -306 to -260 relative to the ATG) required for activation-driven fas upregulation. Sequence analysis revealed the presence of a previously unrecognized composite binding site for both the Sp1 and NF-kappaB transcription factors at positions -295 to -286. Electrophoretic mobility shift assay (EMSA) and supershift analyses of this region documented constitutive binding of Sp1 in unactivated nuclear extracts and inducible binding of p50-p65 NF-kappaB heterodimers after P/I activation. Sp1 and NF-kappaB transcription factor binding was shown to be mutually exclusive by EMSA displacement studies with purified recombinant Sp1 and recombinant p50. The functional contribution of the kappaB-Sp1 composite site in P/I-inducible fas promoter activation was verified by using kappaB-Sp1 concatamers (-295 to -286) in a thymidine kinase promoter-driven reporter construct and native promoter constructs in Jurkat cells overexpressing IkappaB-alpha. Site-directed mutagenesis of the critical guanine nucleotides in the kappaB-Sp1 element documented the essential role of this site in activation-dependent fas promoter induction.  (+info)

RFLAT-1: a new zinc finger transcription factor that activates RANTES gene expression in T lymphocytes. (8/39207)

RANTES (Regulated upon Activation, Normal T cell Expressed and Secreted) is a chemoattractant cytokine (chemokine) important in the generation of inflammatory infiltrate and human immunodeficiency virus entry into immune cells. RANTES is expressed late (3-5 days) after activation in T lymphocytes. Using expression cloning, we identified the first "late" T lymphocyte associated transcription factor and named it "RANTES Factor of Late Activated T Lymphocytes-1" (RFLAT-1). RFLAT-1 is a novel, phosphorylated, zinc finger transcription factor that is expressed in T cells 3 days after activation, coincident with RANTES expression. While Rel proteins play the dominant role in RANTES gene expression in fibroblasts, RFLAT-1 is a strong transactivator for RANTES in T cells.  (+info)

Ethanol consumption is associated with impaired immunity. Our data demonstrate that even a single dose of a biologically relevant concentration (25-150 mM) of ethanol can down-regulate antigen-specific T lymphocyte proliferation. In contrast, ethanol augmented mitogen-induced T cell proliferation, suggesting that its inhibitory effect on antigen-specific T cell proliferation was due to its effects on monocytes (m phi s) rather than on T cells. The immunodepressive effects of ethanol on m phi antigen-presenting cell (APC) capacity were manifested whether alcohol treatment was limited to the antigen uptake-processing period only or was present during the entire period of antigen presentation. These inhibitory effects of ethanol were also evident on both the high-antigen-presenting, Fc gamma RI-negative (-31 +/- 17%), and low-antigen-presenting, Fc gamma RI-positive (-42 +/- 15%) m phi subpopulations. Further analysis demonstrated that ethanol inhibits the production of interleukin-1 beta (IL-1 beta) and
Human and rhesus macaque primary antigen‐specific T cells derived from infected or immunized individuals or animals are a valuable material with which to study cellular immune responses against pathogens and tumors
In this webinar, we feature Dr. Karen Anderson who utilized 3D Flow Analysis to deeply profile antigen specific T cells. Hear about the exciting biology uncovered from these rare cells utilizing this novel technique.
We found a selective increase in T-lymphocyte number in morbid obese subjects, which was mainly caused by an increase in CD4+ T-lymphocytes. Also, in morbid obese subjects TREC content was decreased in all T-lymphocyte subpopulations, demonstrating that the increase in T-lymphocytes is mainly caused by increased proliferation. Moreover, in morbid obese subjects we found increased plasma levels of IL-7 and CCL5, both potent enhancers of T-lymphocyte proliferation. Also, plasma of morbid obese subjects enhanced T-lymphocyte proliferation in vitro.. Finally, both CD4+ and CD8+ T-lymphocytes had some skewing of the TCR repertoire. ...
TY - JOUR. T1 - Cyclosporin A inhibits initiation but not progression of human T cell proliferation triggered by phorbol esters and calcium ionophores. AU - Kumagai, N.. AU - Benedict, S. H.. AU - Mills, G. B.. AU - Gelfand, E. W.. PY - 1988/12/1. Y1 - 1988/12/1. N2 - Cyclosporin A (CsA) is a potent inhibitor of T lymphocyte proliferation induced by Ag and mitogens. In an attempt to further delineate the mechanism of action of CsA, we have examined its effects on T cell proliferation induced by the combination of the phorbol ester, phorbol 12,13-dibutyrate (PDB), and the calcium ionophore, ionomycin. T cells were rendered competent as the result of a 30-min initial incubation with both drugs, after which the drugs were washed out. Competence is defined as the ability to subsequently proliferate in response to exogenously added IL-2 or PDB in the second phase of the culture, but not to synthesize IL-2 or proliferative without these additions. Addition of CsA (1 μg/ml) to the cells in the ...
Identification and characterization of antigen-specific T lymphocytes during the course of an immune response is tedious and indirect. To address this problem, the peptide-major histocompatability complex (MHC) ligand for a given population of T cells was multimerized to make soluble peptide-MHC tetramers. Tetramers of human lymphocyte antigen A2 that were complexed with two different human immunodeficiency virus (HIV)-derived peptides or with a peptide derived from influenza A matrix protein bound to peptide-specific cytotoxic T cells in vitro and to T cells from the blood of HIV-infected individuals. In general, tetramer binding correlated well with cytotoxicity assays. This approach should be useful in the analysis of T cells specific for infectious agents, tumors, and autoantigens. ...
Transmembrane signaling of normal human T cells was explored with mAbs directed at TCR, CD2, CD4, CD5, or CD8 antigens and highly purified CD4+ T cells and CD8+ T cells. Our experiments explicitly show that: (a) crosslinkage of TCR with the CD2 antigen, and not independent crosslinking of TCR and of CD2 antigen or crosslinking of either protein with the CD4 or CD8 antigen induces significant proliferation independent of co-stimulatory signals (e.g., accessory cells, recombinant lymphokines, or tumor promoter), (b) F(ab)2 fragments of mAb directed at the TCR and F(ab)2 anti-CD2, crosslinked with F(ab)2 fragments of rabbit anti-mouse IgG, promote the proliferation of highly purified T cells, (c) a prompt and sustained increase in intracellular free Ca2+ concentration results from crosslinkage of TCR with the CD2 antigen, (d) T cell proliferation induced by this novel approach is curtailed by EGTA and by direct or competitive inhibitors of PKC, (e) crosslinkage of TCR with the CD2 antigen ...
If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library, or send a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. ...
Immunotherapy treatments for cancer are becoming increasingly successful, however to further improve our understanding of the T-cell recognition involved in effective responses and to encourage moves towards the development of personalised treatments for leukaemia immunotherapy, precise antigenic targets in individual patients have been identified. Cellular arrays using peptide-MHC (pMHC) tetramers allow the simultaneous detection of different antigen specific T-cell populations naturally circulating in patients and normal donors. We have developed the pMHC array to detect CD8+ T-cell populations in leukaemia patients that recognise epitopes within viral antigens (cytomegalovirus (CMV) and influenza (Flu)) and leukaemia antigens (including Per Arnt Sim domain 1 (PASD1), MelanA, Wilms Tumour (WT1) and tyrosinase). We show that the pMHC array is at least as sensitive as flow cytometry and has the potential to rapidly identify more than 40 specific T-cell populations in a small sample of T-cells ...
Lentiviral vectors have emerged as efficient tools for investigating T cell biology through their ability to efficiently deliver transgene expression into both dividing and nondividing cells. Such lentiviral vectors have the potential to infect a wide variety of cell types. However, despite this advantage, the ability to transduce primary human T cells remains challenging and methods to achieve efficient gene transfer are often time consuming and expensive. We describe a method for generating lentivirus that is simple to perform and does not require the purchase of non-standard equipment to transduce primary human T cells. Therefore, we provide an optimized protocol that is easy to implement and allow transduction with high efficiency and reproducibility.
Mature T lymphocytes of the CD8 or CD4 classes bear αβ T cell receptors (TCR) that are specific for a molecular complex consisting of a major histocompatibility complex class I or II (MHC class I or II) molecule bound to a unique self or foreign peptide
Polyfunctional CD4 or CD8 T cells are proposed to represent a correlate of immune control for persistent viruses as well as for vaccine mediated protection against infection. A well-suited methodology to study complex functional phenotypes of antiviral T cells is the combined staining of intracellular cytokines and phenotypic marker expression using polychromatic flow cytometry. In this study we analyzed the effect of an overnight resting period at 37°C on the quantity and functionality of HIV-1, EBV, CMV, HBV and HCV specific CD4 and CD8 T-cell responses in a cohort of 21 individuals. We quantified total antigen specific T cells by multimer staining and used 10-color intracellular cytokine staining (ICS) to determine IFNγ, TNFα, IL2 and MIP1β production. After an overnight resting significantly higher numbers of functionally active T cells were detectable by ICS for all tested antigen specificities, whereas the total number of antigen specific T cells determined by multimer staining remained
The CD8 antigen is a disulfide-linked dimer, which exists either as a CD8α homodimer or as a CD8α/β heterodimer. CD8α is required for surface expression of CD8β. The molecular weight of each monomer of α or β is approximately 32-34 kDa. CD8 binds to a non-polymorphic domain (α3 domain) of MHC Class I molecules. CD8 is expressed on a subset of human peripheral blood T lymphocytes. A subset of NK cells possess the CD8 antigen but show low to medium density of expression. CD8α homodimer is expressed by NK cells and γ/δ+ T cells. CD8 is also present on most thymocytes where it is frequently co-expressed with CD4, and on a subpopulation of bone marrow cells. The CD8 molecule acts with the T Cell Receptor (TCR) as a coreceptor for MHC class I restricted antigen recognition. CD8 is widely used as a marker of cytotoxic T lymphocytes. *Alexa Fluor and Pacific Blue are registered trademarks of Molecular Probes, Inc ...
Effect of three kinds of anaesthetic drugs on postoperative recovery, regulatory T cells and T lymphoid cells in elderly patients
The CD2 antigen (LFA-2) is a monomeric 50 kDa glycoprotein. It was formerly described as the sheep red blood cell receptor, causing T-cell rosetting, and has been identified as the ligand for CD58 (LFA-3). It is also a receptor for CD48, CD59 and CD15, which binds to the multimeric form of CD2. CD2 is present on the majority of normal human peripheral blood T lymphocytes and a high percentage of NK cells. It is also expressed by all thymocytes ...
The data in this paper show that MD-1 is not associated directly with CD80/CD86, DEC205, or OX2 on the membrane of functional DC (Fig. 3⇑). However, inhibition of MD-1 synthesis achieved by incubating DC with the ODN-1 blocked MD-1 synthesis and then indirectly inhibited up-regulation of the costimulatory molecules CD80/CD86 in response to LPS (Fig. 2⇑). These ODN-1-altered DC-stimulated Th2-type cytokine production instead of Th1 cytokines when cultured with allogeneic responder splenocytes (Table I⇑), and proliferation and CTL generation was not seen. Instead, there was generation of cells that could suppress in a secondary test culture the allogeneic response of untreated C3H splenic T cells to unaltered allogeneic DC (Table II⇑). Generation of these suppressor cells was dependent on persistent OX2 expression on the ODN-1-treated DC, because anti-OX2 mAb blocked the effect. The ability of ODN-1-treated DC to enhance allograft survival in vivo via an OX2-dependent pathway (Fig. 4⇑) ...
Characterization of human leukocyte antigen (HLA) class I restricted epitopes derived from viral pathogens is imperative for formulating therapeutic interventions, as well as for vaccine design and monitoring. Sensitive, easy and cost-effective assays that measure the frequency of antigen-specific T lymphocytes are crucial for evaluating and improving vaccines and therapies. This paper reviews the ELISPOT technique that allows for quantifying HIV-specific T lymphocytes at the single cell level from peripheral blood by detection of antigen-induced cytokine secretion. The assay can be used successfully to quantify T cell immune responses in humans infected with different pathogens and to assess T cell immunogenicity of vaccines in phase I/II and III clinical trials. This review focuses on the ELISPOT methodology and discusses how it can be standardized and potentially used by multiple international laboratories attached to clinical trial sites.
Depasquale, jardieu P.; Fraker, P J.; and Luecke, R W., "Regeneration of t-cell helper function in zinc deficient adult a/j mice. Abstr." (1978). Subject Strain Bibliography 1978. 1286 ...
functional immune Searched from official sources arount the web with simple content and resource link From any languages in different countries.
Interleukin 2 (IL-2, aldesleukin) was discovered as a T cell growth factor more than 30 years ago. IL-2 was the first human cytokine used therapeutically. IL-2 induces antigen specific T cells, and two important lymphocyte subsets: regulatory T cells (T-regs) and natural killer cells (NK) cells. T-regs have a critical role in self-tolerance and pathogenesis of autoimmune disease or graft versus host disease (GVHD), and they have been extensively studied in solid tumors, hematologic malignancies, viral hepatitis, and HIV infections. NK cells have a unique role in bridging innate and adaptive immunity. NK cells facilitate hematopoietic stem cell (HSC) engraftment reduce GVHD and increase graft-versus-leukemia (GVL) effects. NK cells have important roles on pathogenesis of malignancies, autoimmune disease and AIDS. Conventional dose IL-2 treatment promotes marked expansion of regulatory T cells, and NK cells but is associated with significant side effects. However, much lower doses of interleukin-2 ...
It is suggested that human γδ T cells play significant roles during intracellular infections, such as tuberculosis (20), malaria (21), ehlrichosis (22), and many others (23, 24, 25, 26, 27, 28, 29, 30, 31). Evidence indicates that human T cells bearing Vγ2Vδ2-TCR, which constitute the vast majority of γδ T cells in healthy adults, respond to unique Ags in the extracts and/or supernatants of these bacteria and protozoa and are activated with respect to proliferation, cytokine production, and cytotoxic activity (17). These Ags include nonpeptide molecules such as a wide variety of small organic pyrophosphomonoesters (3, 4, 5, 7) and alkylamines (12) as well as unprocessed protein Ags (32, 33, 34). Although it has been indicated that the response takes place in a Vγ2Vδ2-TCR-dependent manner based on substantial evidence including the TCR gene transfer studies (15), knowledge of how human γδ T cells recognize such molecules has remained elusive.. It was indicated previously that activation ...
Freshly isolated, human peripheral blood T (PBT) cells are largely resistant to the apoptotic effects of anti-CD3 monoclonal antibody, ionomycin, or phorbol 12-myristate 13-acetate (PMA). We demonstrate here, however, that PBT cells, including both CD4+ and CD8+ cell populations, can be readily induced to undergo apoptosis when cocultured with either autologous or allogeneic monocytes (Mo) in PMA-containing medium. Incubation of PBT cells with Mo at a ratio of 1:1 for 18 hr resulted in maximal levels (80%) of apoptotic cell death. The mechanism whereby Mo enable PBT cells to undergo apoptosis in PMA-containing medium appeared to depend on cell-cell contact or close proximity between Mo and PBT cells rather than solely via soluble mediators. It was demonstrated that Mo acquire the ability to prime PBT cells for apoptosis after treatment with PMA and that treated Mo maintain this ability even after fixation with formaldehyde. It was also found that once PBT cells became primed for apoptosis by ...
Recent clinical trials have demonstrated that a type of immune cell called T lymphocytes may play an important role in inducing the regression of different cancers, in particular of blood cancers. Other immune cells called macrophages accumulate in solid tumors and are numerous in growing tumors of poor prognosis. Based on these results, many people consider that, for cancer patients, lymphocytes are "good guys" and macrophages are "bad guys". However, the reality is likely to be not that Manichean. Indeed, immune responses that are efficient against infection require efficient cooperations between different cell types. We have designed a local treatment for tumor-bearing mice which has been conceived on the model of an anti-infectious response, as if there was an infection at the level of the tumor. This resulted in a systematic tumor regression.. We perform an accurate kinetic analysis of the immune response by combining immunofluorescence in tumor sections with a global analysis of the ...
Melanie Chabaud has been awarded a Long-Term Postdoctoral Fellowship from the Human Frontier Science Program (HFSP) to investigate the molecular events leading to T cell arrest.. T cells constantly migrate through the peripheral lymphoid organs, briefly pausing to sample the antigenic peptides presented by antigen presenting cells. Long-lasting interactions with antigen presenting cells, resulting in sustained signalling, is required to generate a robust immune response. But what makes them stop and what happens when they do?. Melanie believes that increased membrane tension in T cells triggers the critical events leading to T cell arrest, including reorganisation of the cytoskeleton and initiation of signalling cascades. Using purpose-built microchambers, she can observe T cells under the microscope as they recognise their target antigen and stop. She can then observe the actin cytoskeleton remodelling and other changes at the molecular level.. After completing her Ph.D. at the Institut Curie ...
Tissue in monkeys infected with a close relative of HIV can ramp up production of a type of T cell that actually weakens the bodys attack against the invading virus. The discovery, in lymph nodes draining the intestinal tract, could help explain how the HIV virus evades the bodys immune defenses. [en español]
T lymphocytes are cells of the immune system that produce factors regulating the function of other cells of immune system thereby shaping the systemic immune response. CD4+ T lymphocytes play a crucial role in directing the immune responses against foreign pathogens, damaged or transformed cells. However, when deregulated, the T cells may also mediate a number of autoimmune diseases such as type-1 diabetes, rheumatoid arthritis and multiple sclerosis. In addition, activated T cells mediate graft rejection and may significantly affect the development and progression of inflammatory diseases such as cardiovascular disease and stroke. Therefore, understanding the complex molecular mechanisms that regulate T cell effector functions may lead to development of therapeutic strategies designed to treat and/or alleviate T cell-mediated immune system disorders in humans. Our research focuses on unraveling the cellular and molecular mechanisms regulating T cell activation and communication with other cells ...
Gene therapy. A researcher prepares culture dishes of gene-corrected T-lymphocytes. T-lymphocytes are white blood cells that play a crucial role in the immune system. This stock of lymphocytes is derived from cells taken from a patient with a suppressed immune system. The original sample was genetically altered to make the cells more active, and then cultured to produce large numbers. The cells can then be reintroduced into the patient to help restore the immune system. - Stock Image G210/0538
Coloured scanning electron micrograph (SEM) of two T-lymphocyte white blood cells. Characteristic of T-lymphocytes are the long microvilli projecting from the cell surface. T-lymphocytes are susceptible to infection by the Human Immunodeficiency Virus (HIV), the causative agent of AIDS. Magnification 1300x at 35mm. - Stock Image C023/9649
CD3 is an essential T cell co-receptorand defines T cell lineage. CD3is therefore an ideal T cell marker. This mini-review explains the structure of CD3, the genes involved in its expression, its function and the signal transduction pathways mediated by CD3 complex.
I was wondering if my transfections are not working because Im using the wrong cell line, I have been using HEK293, but is HEK293T better for transient and stable transfection? Also is there a difference with vendors (ie, some have better cell lines? lower passages perhaps?). Im just getting frustrated with these transfections that do not work. If anyone has any suggestions I would greatly appreciate it ...
Looking for the meaning of t-lymphocytes? Find out what is the meaning of t-lymphocytes on Phrases.net! The Webs largest and most authoritative phrases and idioms resource.
1MWA: Structural comparison of allogeneic and syngeneic T cell receptor-peptide-major histocompatibility complex complexes: a buried alloreactive mutation subtly alters peptide presentation substantially increasing V(beta) Interactions.
Description of disease T cell, peripheral. Treatment T cell, peripheral. Symptoms and causes T cell, peripheral Prophylaxis T cell, peripheral
Improved cancer therapy using a combination treatment with tumour-reactive T-lymphocytes obtained by an in vitro method for expansion and activation of tumour-reactive lymphocytes, in particular CD4+
We know that the immune system of a young can react faster and more effectively against a microbe than a senior one.. During his life, a human being is faced with many microbes, fought fortunately in most cases victoriously by the immune system . Most of the time, this victorious battle takes place without us being aware of it. Sometimes we suffer from fever and other symptoms, consequences of this struggle. There are also germs (especially viruses) that are controlled and mitigated by the body, but that it can not make them disappear completely.. There is probably a price to pay : we believe that these chronic infections cause the immune system to use a lot of its energy, and with time, it is no longer able to react sufficiently quickly and effectively against the new infections. Its the same with vaccination in elderly people . To create a sufficient protection, it is necessary to have a fully functional immune system. [3]. # Epitalon has been tested successfully for many years (1992-2007) ...
We know that the immune system of a young can react faster and more effectively against a microbe than a senior one.. During his life, a human being is faced with many microbes, fought fortunately in most cases victoriously by the immune system . Most of the time, this victorious battle takes place without us being aware of it. Sometimes we suffer from fever and other symptoms, consequences of this struggle. There are also germs (especially viruses) that are controlled and mitigated by the body, but that it can not make them disappear completely.. There is probably a price to pay : we believe that these chronic infections cause the immune system to use a lot of its energy, and with time, it is no longer able to react sufficiently quickly and effectively against the new infections. Its the same with vaccination in elderly people . To create a sufficient protection, it is necessary to have a fully functional immune system. [3]. # Epitalon has been tested successfully for many years (1992-2007) ...
If you DO get infected by bacteria or fungi resistent to antibiotics and antifungal drugs, your immune system will be your only defense. So you need to learn how to have a strong and functional immune system. Until science gives us new cures. ...
The test evaluates and monitors T-lymphocyte helper cells (CD4) and inducer T-cells. T-lymphocyte helper cells (such as CD4 cells) play a critical role in orchestrating the response to infections. After activation of the immune response, T-lymphocyte suppressor cells (such as CD8) deactivate the immune cells fighting t
IL-7R[alpha] is one component of the heterodimeric IL-7R[alpha] receptor, and signaling through this receptor is essential for murine T and B cell development as well as human T cell development. IL-7R[alpha] signaling is ...
Baptism Preparation, Ages 0 - 7 Years The Importance of Preparation and How to Begin: The Archdiocese of Galveston-Houston and the Co-Cathedral of
声门癌放疗,15例T2b期声门鳞癌放射治疗疗效分析顾科 张晓萍 傅晓艳[摘要] 目的 分析15例T2b期声门鳞癌的放射治疗效果,复习文献,讨论提高T2b期声门鳞癌放疗生存率的方法。 方法 1985年至1994年江苏省肿瘤医院和常州市肿瘤医院收治T2b期声门鳞癌15例,均行单纯放射治疗,局部5
若第二階段無法順利清除病原體3則會進入第三階段4前面兩階段的免疫細胞會提供抗原資訊給淋巴器官3B細胞及T細胞在淋巴器官內被活化增生後3產生專一性3即可更有效率消滅致病 ...
View the latest weather forecasts, maps, news and alerts on Yahoo Weather. Find local weather forecasts for Monson, United States throughout the world
Looking for Major histocompatability complex? Find out information about Major histocompatability complex. In vertebrates, a family of genes that encode cell surface glycoproteins that regulate interactions among cells of the immune system, some components of the... Explanation of Major histocompatability complex
We next examined the effect of thalidomide on cytokine production by the three T cell populations when stimulated by anti-CD3 in the absence of exogenous IL-2. Thalidomide induced a consistent concentration-dependent increase in IL-2 production at 12 h (time of peak production determined in preliminary kinetic experiments), in CD8+ and in bulk T cells (Fig. 3,A). Although a trend towards a thalidomide dose response in IL-2 production by purified CD4+ T cells was apparent, production of this cytokine was modest in comparison to that of bulk and CD8+ populations. Exposure to thalidomide consistently increased IFN-γ production by all three T cell populations. Since there was no clear peak in production of the latter cytokine, the results of a kinetic experiment are shown for CD4+ and CD8+ T cells (Fig. 3,B) using a single concentration of thalidomide (10 μg/ml). Again, the drug induced relatively greater production of IFN-γ by purified CD8+ T cells. However, the thalidomide-induced augmentation ...
Rubin, B; Hertel, wulff B.; and Kimura, A, "Alloantigen-specific idiotype-bearing receptors on mouse t lymphocytes. I. Specificity characterization and genetic association with the heavy-chain igg allotype." (1979). Subject Strain Bibliography 1979. 4576 ...
The migration of T lymphocytes is a vital component of the immune system, with roles in immunosurveillance and inflammation. The role of Phosphoinositide 3-kinase within T lymphocyte migration is unclear, with some evidence that it may be a disposable signal. Here, using Staphylococcal Enterotoxin B activated peripheral blood mononuclear cells and the T cell line CEM cells, the role of Phosphoinositide 3-kinase and its downstream kinases was investigated. CCL22 mediated CEM cell migration and CXCL12 mediated peripheral blood mononuclear cell migration were shown to be independent of Phosphoinositide 3-kinase using several different broad-spectrum Phosphoinositide 3-kinase inhibitors. However, these cells were Akt-dependent, as demonstrated by incubation with the Akt inhibitor Akti-1/2. Differences in the effect of the inhibitors on Akt activity were discovered, indicating that either Akt can be activated in the absence of Phosphoinositide 3-kinase, or differences exist regarding the relative ...
0065]Following incubation of the APCs with effector T lymphocytes obtained from a mammal immunized against the pathogen, the inventive method comprises screening for an immune response from the effector T lymphocytes. The immune response can be any suitable effector T lymphocyte immune response known in the art, including, but not limited to, cytokine secretion, effector T cell cytotoxicity, and immune activation of effector T cells. Preferably, the inventive method comprises screening for secretion by the effector T lymphocytes. In this regard, cytokine secretion from an effector T lymphocyte contacting an APC indicates that the effector T lymphocyte recognizes the antigen produced and displayed by the APC. Furthermore, it is well known in the art that effector T lymphocytes, such as effector helper T effector lymphocytes, secrete cytokines upon antigen recognition which promote different activities. In this regard, inflammatory or Th1 CD4 T cells produce interleukin-2 (IL-2), interferon gamma ...
Description of disease T-suppressor cell. Treatment T-suppressor cell. Symptoms and causes T-suppressor cell Prophylaxis T-suppressor cell
Author Summary There is a desperate need for the development of new therapeutic strategies to eradicate HIV infection. HIV actively subverts the potent natural immune responses against it, particularly cellular cytotoxic T lymphocyte (CTL) responses. The development of a therapy that allows long-lived immune self-containment of HIV and restoration of these CTL responses by the host would be ideal. Through genetic manipulation of human blood-forming stem cells, we introduced a molecule- an HIV-targeting T cell receptor (TCR)-that allowed the generation of functional HIV-specific CTLs following differentiation within human tissues in a humanized mouse model. To assess if these newly developed, HIV-specific CTLs can allow active suppression of HIV replication, we infected these mice with HIV. We found that the development of genetically modified, HIV-specific CTLs in these mice results in the presence of a functional antiviral CTL response in vivo that significantly lowers viral replication following HIV
Our study shows that (1) CD8+ T‐cell activation and memory generation occurs in response to atherogenic diet feeding in apoE−/− mice; (2) A small fraction of these activated CD8+ T cells in apoE−/− mice are antigen‐specific that are reactive to the p210 peptide fragment of apoB‐100, supporting the notion that p210 is a self‐antigen; and (3) Immunization of apoE−/− mice with the p210 peptide fragment altered the immune‐dominant epitopes, concurrent with reduced atherosclerosis. This has significant implications in our efforts to characterize immune functions in atherosclerosis and develop potential apoB‐100 peptide‐based vaccine candidates.4, 22. T‐cell activation is a hallmark feature of adaptive immunity. Naïve T cells undergo activation and clonal expansion of antigen‐specific T cells when encountering antigen presented by antigen‐presenting cells in the context of costimulatory signaling. Such antigen‐specific T cells further differentiate into effector and ...
CD27 is a lymphocyte-specific member of the TNF receptor family and has a TNF-related transmembrane ligand, CD70. The CD27/CD70 receptor-ligand pair cooperates with the TCR in the regulation of the peripheral T cell response. The study presented here reveals that CD27 may play a similar role in thymic pre-T cell development. We have previously cloned the cDNA encoding murine CD27, prepared specific mAbs and observed that murine CD27 is expressed on virtually all thymocytes, with the exception of a subpopulation of CD4-8- precursor T cells. It is shown here that induction of murine CD27 expression occurs at the transition from the CD4-8-25+ to the CD4-8-25- precursor T cell stage and is regulated by the pre-TCR. Therefore, we investigated whether CD27 contributes to pre-TCR-mediated thymocyte development. Pre-TCR function was mimicked by the induction of CD3 signaling in thymocytes of recombination activating gene (RAG)-deficient mice. This in vivo anti-CD3 epsilon mAb treatment induces an about ...
In cellular signal transduction, scaffold proteins provide binding sites to organize signaling proteins into supramolecular complexes and act as nodes in the signaling network. Furthermore, multivalent interactions between the scaffold and other signaling proteins contribute to the formation of protein microclusters. Such microclusters are prominent in early T cell signaling. Here, we explored the minimal structural requirement for a scaffold protein by coupling multiple copies of a proline-rich peptide corresponding to an interaction motif for the SH3 domain of the adaptor protein GADS to an N-(2-hydroxypropyl)methacrylamide polymer backbone. When added to GADS-containing cell lysates, these scaffolds (but not individual peptides) promoted the binding of GADS to peptide microarrays. This can be explained by the cross-linking of GADS into larger complexes. Furthermore, following import into Jurkat T cell leukemia cells, this synthetic scaffold enhanced the formation of microclusters of signaling ...
Adoptive T cell therapy to treat cancer in combination with re-directing specificity through T cell receptor (TCR) gene transfer, represents an effective therapeutic option. However, reduced effector responses due to the immunosuppressive tumour microenvironment and insufficient long-term engraftment of transferred cells represent two potential limitations. Tumours often employ mechanisms to inhibit T cell responses including secretion of TGFβ and depleting the tumour microenvironment of amino acids. The main aim of this PhD project was to develop a strategy to enhance T cell function for tumour therapy. The mammalian target of rapamycin (mTOR) pathway regulates CD8 T cell differentiation such that high mTOR activation leads to enhanced effector whilst low mTOR activation leads to increased T cell memory formation. Two retrovirus constructs have been designed whereby one expresses the positive mTOR regulator Rheb and the other expresses the negative mTOR regulator Pras40. Rheb transduction into ...
In this report we show that it is possible to detect the expression of a G protein-coupled receptor, the A2AR, in human lymphocytes both on the basis of a functional assay (cAMP accumulation) and by flow cytometry using an antireceptor mAb. We were able to describe for the first time the distribution of A2AR among minor T cell subpopulations through the use of a combination of anti-A2AR mAb and mAbs that recognize T cell surface markers or cytokines. The principle findings of this study are that much higher levels of A2AR expression is found in T cells than in B cells (Fig. 3) and higher levels of cytokines are detected in activated T cells that express A2AR than in activated T cells that do not express these receptors (Figs. 6 and 7).. The detection of higher levels of cytokines among A2AR+ cells is surprising because A2AR-mediated signaling antagonizes the effects of T cell activation (Koshiba et al., 1997; Huang et al., 1997). Therefore, we expected that cytokine secretion would be the lowest ...
Background Different types of membrane microdomains (rafts) have been postulated to be present in the rear and front of polarized migrating T-lymphocytes. reorganization in human being T-lymphocytes and possible roles of flotillins in lymphocyte polarization. Results We studied flotillin reorganization and lateral mobility at the plasma membrane using immunofluorescence staining and FRAP (fluorescence recovery after photobleaching). We show that flotillins redistribute early upon chemokine stimulation and form very stable caps in the uropods of human peripheral blood T-lymphocytes colocalizing with the adhesion molecule PSGL-1 and activated ezrin/radixin/moesin (ERM) proteins. Chemokine-induced formation of stable flotillin caps requires Haloperidol (Haldol) integrity and dynamics of the actin cytoskeleton but is not abolished by inhibitors suppressing Rho-kinase or myosin II activity. Tagged flotillin-2 and flotillin-1 coexpressed in T-lymphocytes but Haloperidol (Haldol) not singly expressed ...
Tumor cell-derived exosomes (TEX) suppress functions of immune cells. Here, changes in the gene profiles of primary human T lymphocytes exposed in vitro to exosomes were evaluated. CD4(+) Tconv, CD8(+) T or CD4(+) CD39(+) Treg were isolated from normal donors peripheral blood and co-incubated with TEX or exosomes
The human T cell receptor for antigen (Ti) has recently been identified on IL-2 dependent T cell clones as a 90 kd disulfide-linked heterodimer comprised of one 49-51 kd alpha (alpha) and one 43 kd beta (beta) chain. These subunits are noncovalently associated with a monomorphic 20-25 kd T3 molecule. Here, we produce monoclonal antibodies to a human tumor (REX) derived from an earlier stage of thymic differentiation in order to determine whether clonotypic structures are expressed and to define the ontogeny of Ti. The results of SDS-PAGE and peptide map analyses indicate that an homologous T3-associated heterodimer is synthesized and expressed by REX. This glycoprotein shares several peptides in common with clonotypic structures on an IL-2 dependent T cell clone. In addition, similar Ti related molecules appear during intrathymic ontogeny in parallel with surface T3 expression. The latter findings provide the structural basis for the immunological competence observed exclusively within the T3+ thymocyte
Ertl, Hildegund; Gerike, Rainer und Koszinowski, Ulrich H. (1977): Virus-Specific T-Cell Sensitization. Requirements for vaccinia virus specific T cell sensitization in vivo. In: Journal of immunogenetics, Vol. 4: S. 515-522 ...
A membrane bound member of the TNF superfamily that is expressed on activated B-LYMPHOCYTES; MACROPHAGES; and DENDRITIC CELLS. The ligand is specific for the 4-1BB RECEPTOR and may play a role in inducing the proliferation of activated peripheral blood T-LYMPHOCYTES ...
Video articles in JoVE about sequence alignment include Semi-automated Biopanning of Bacterial Display Libraries for Peptide Affinity Reagent Discovery and Analysis of Resulting Isolates, Creating and Applying a Reference to Facilitate the Discussion and Classification of Proteins in a Diverse Group, A Practical Guide to Phylogenetics for Nonexperts, Using Phylogenetic Analysis to Investigate Eukaryotic Gene Origin, Investigating Protein Sequence-structure-dynamics Relationships with Bio3D-web, Protein WISDOM: A Workbench for In silico De novo Design of BioMolecules, CAPRRESI: Chimera Assembly by Plasmid Recovery and Restriction Enzyme Site Insertion, Mapping Genome-wide Accessible Chromatin in Primary Human T Lymphocytes by ATAC-Seq, Isolation of Fidelity Variants of RNA Viruses and Characterization of Virus Mutation Frequency, Enhanced Reduced Representation Bisulfite Sequencing for Assessment of DNA Methylation at Base Pair Resolution, Optimization of Synthetic Proteins:
Therapies that Ag-specifically target pathologic T lymphocytes responsible for multiple sclerosis (MS) and other autoimmune diseases would be expected to have improved therapeutic indices compared with Ag-nonspecific therapies. We have developed a cellular immunotherapy that uses chimeric receptors to selectively redirect therapeutic T cells against myelin basic protein (MBP)-specific T lymphocytes implicated in MS. We generated two heterodimeric receptors that genetically link the human MBP84-102 epitope to HLA-DR2 and either incorporate or lack a TCRzeta signaling domain. The Ag-MHC domain serves as a bait, binding the TCR of MBP-specific target cells. The zeta signaling region stimulates the therapeutic cell after cognate T cell engagement. Both receptors were well expressed on primary T cells or T hybridomas using a tricistronic (alpha, beta, green fluorescent protein) retroviral expression system. MBP-DR2-zeta-, but not MBP-DR2, modified CTL were specifically stimulated by cognate MBP-specific T
At first glance, an association of a CD4 T cell-mediated disease with HLA class II gene products, whose function is to present peptides to CD4 T cells, appears easily explainable. Over the years, the most obvious, nonexclusive theories have been tested: instability and poor peptide binding of diabetogenic HLA class II molecules (6), unique peptide repertoire of the same molecules (7), T cells focused on the recognition of HLA-DQβ57 (8), failed thymic selection of autoreactive T cells (9), and abnormal T-cell binding to autoimmune peptide-MHC complexes (10). While all of those might bear truth and give some level of understanding of what the β57 residue might do, none could formally associate the mutation to a molecular mechanism leading to diabetes. The closest one to explaining the association of the same mutation with a disease was in the context of celiac disease, where the same HLA-DQ molecules are strongly predisposing to onset and also promote a frequent association with type 1 diabetes ...
T cells are an important part of the immune system. However, they are not only capable of destroying pathogens. They can also become harmful themselves. Researchers at the Technical University of Munich and the University Medical Center of the Johannes Gutenberg University Mainz have discovered the conditions under which certain T cells become the kind of pathogenic T cells associated with multiple sclerosis. Their results explain why certain treatments are not consistently effective.
The CD2 receptor on T lymphocytes is essential for T cell adhesion and stimulation by antigen presenting cells (APCs). Blockade of CD2 function is immunosuppressive in both model systems and humans, indicating the importance of CD2 for the cellular immune response. Although the affinity of the molecular interaction between CD2 and its counter-receptor, CD58, is relatively low when measured in solution, this interaction mediates tight adhesion within the 2D cell-cell interface. To understand the mechanisms responsible for regulating the avidity of the CD2-CD58 interaction, we measured the number, affinity, and lateral mobility of CD2 molecules on resting and activated T cells. Cell activation caused a 1.5-fold increase in the number of CD2 sites on the cell surface, and the 2D affinity of CD2 for CD58 increased by 2.5-fold. The combination of T cell activation and CD2 ligation to CD58 decreased the laterally mobile fraction of the ligated CD2. Together, these changes would substantially enhance CD2
by Barbara Stranger, Ye CJ, Feng T, Kwon HK, Raj T, Wilson MT, Asinovski N, McCabe C, Lee MH, Frohlich I, Paik HI, Zaitlen N, Hacohen N, De Jager P, Mathis D, Regev A, Benoist C. T lymphocyte activation by antigen conditions adaptive immune responses and immunopathologies, but we know little about its variation in humans and its genetic or environmental roots. We analyzed gene expression in CD4(+) T cells during unbiased activation or in T helper 17 (T(H)17) conditions from 348 healthy participants representing European, Asian, and African ancestries. We observed interindividual variability, most marked for cytokine transcripts, with clear biases on the basis of ancestry, and following patterns more complex than simple T(H)1/2/17 partitions. We identified 39 genetic loci specifically associated in cis with activated gene expression. We further fine-mapped and validated a single-base variant that modulates YY1 binding and the activity of an enhancer element controlling the autoimmune-associated ...
A central question in T cell development is what makes cortical thymocytes respond to stimulation in a qualitatively different way than any other thymocyte subset. Part of the answer is that AP-1 function changes drastically at two stages of T cell development. It undergoes striking down-regulation as thymocytes differentiate from immature, CD4^-CD8^- double-negative (DN) TCR^- thymocytes to CD4^+CD8^+ double-positive (DP) TCR^(lo) cortical cells, and then returns in the cells that mature to TCR^(high), CD4^+CD8^- or CD4^-CD8^+ single-positive (SP) thymocytes. At all three stages, the jun family mRNAs can be induced similarly. However, we demonstrate that DP cortical thymocytes are specifically impaired in c-fos and fosB mRNA induction, even when stimuli are used that optimize survival of the cells and a form of in vitro maturation. fra-2 expression is induction independent but much lower in DP cells than in the other subsets. Overall Fos family protein induction accordingly is severely ...
This gene was identified by the up-regulation of its expression upon Epstein-Barr virus infection of primary B lymphocytes. This gene is predicted to encode a G protein-coupled receptor that is most closely related to the thrombin receptor. Expression of this gene was detected in B-lymphocyte cell lines and lymphoid tissues but not in T-lymphocyte cell lines or peripheral blood T lymphocytes. The function of this gene is unknown ...
To determine if mesothelin is recognized by CD8+ T cells, we screened antigen-pulsed T2 cells in a quantitative ELISPOT-based assay using pre- and postvaccination CD8+ T cell-enriched PBLs from the 14 patients treated previously with the allogeneic, GM-CSF-secreting pancreatic tumor vaccine. Previously, we reported the association of in vivo postvaccination DTH responses to autologous tumor in three out of eight patients receiving the highest two doses of vaccine. PBLs obtained before vaccination and 28 d after the first vaccination were initially analyzed. T2-A3 cells pulsed with the two A3 binding epitopes were incubated overnight with CD8+ T cell-enriched lymphocytes isolated from the peripheral blood of patients 11 (an A3 non-DTH responder) and 13 (an A3 DTH responder), and analyzed using an IFN-γ ELISPOT assay. The ELISPOT assay was chosen because it requires relatively few lymphocytes, is among the most sensitive in vitro assays for quantitating antigen-specific T cells, and correlates ...
Medullary thymic epithelial cells (mTECs) are critical in establishing and maintaining the appropriate microenvironment for negative selection and maturation of immunocompetent T cells with a self-tolerant T cell antigen receptor repertoire. Cues that direct proliferation and maturation of mTECs are provided by members of the tumor necrosis factor (TNF) superfamily expressed on developing thymocytes. Here we demonstrate a negative role of the morphogen TGF-β in tempering these signals under physiological conditions, limiting both growth and function of the thymic medulla. Eliminating TGF-β signaling specifically in TECs or by pharmacological means increased the size of the mTEC compartment, enhanced negative selection and functional maturation of medullary thymocytes as well as the production of regulatory T cells, thus reducing the autoreactive potential of peripheral T cells.
T and B-lymphocytes play an important role in an adaptive immune response. Communication between these two cells may result in either a humoral immune response or tolerance. Communication between T and B-lymphocytes involves a number of inducible cell surface molecules on both T and B-lymphocytes. It was the aim of this project to gain a greater understanding of the role of CD40 in the dynamic communication that occurs between naïve T-lymphocytes and resting B-lymphocytes during cognate communication. Because in vivo antigen specific T-lymphocytes are at low frequency, it is difficult to examine antigen-specific naïve T-lymphocytes. Thus, an in vitro system employing naïve antigen-specific T cell receptor (TCR) transgenic T cells and small resting B-lymphocytes that did not express CD40 was devised to examine the role of CD40 in cognate communication between naïve T-lymphocytes and resting B-lymphocytes. Upon recognition of antigen on resting B-lymphocytes that expressed CD40, T-lymphocytes
Figure 1: CD4 T cell proliferative responses to control antigens (PPD, KLH, TT and HA), and peptide libraries derived from the sequences of Dstls two antibodies (chimeric, top, and humanized, bottom). The cell division index (CDI) is determined as a ratio of the proportion of CFSE-dim [divided] cells in the stimulated versus unstimulated samples. 40 different donor samples were tested and the cumulative results are shown. Lower scores are indicative of reduced potential antigenicity in humans. Data reproduced by kind permission of Dstl.. Before considering whether to move the treatment into clinical trials, the Dstl team wanted to gather as much information as possible on the potential immunogenicity of their novel antibody construct. For this, they used ProImmunes Immunogenicity services and requested that ProImmune test both antibodies in CFSE T cell proliferation assays. Briefly, CD4+ T cell proliferation in response to overlapping peptide libraries generated from the sequences of each ...
The main finding reported here is that production of the signature Th17 cytokine IL-17A is more strongly associated with AIHA than are Th1 IFN-γ responses, which have previously been described in the disease. Not only were the levels of IL-17A, but not IFN-γ, significantly increased in the serum of patients versus healthy control donors, but IL-17A was the more prominent cytokine in the responses of patients T cells to autologous RBC used as a source of antigen. It was also confirmed that a specific autoantigen, the RhD protein,12-14,19 contains epitopes that elicit such IL-17A responses. These results raise the possibility that autoreactive Th17 cells contribute to pathogenic helper T-cell activity in AIHA, and are responsible for at least some of the effects previously attributed to the Th1 subset.. Following the recognition that Th17 cells constitute a distinct helper subpopulation, the pathogenesis of many inflammatory immune diseases has been re-examined and it has become clear that ...
While emerging proof indicates that dendritic cells (DC) play a central part in the pathogenesis of multiple sclerosis (MS), their modulation with immunoregulatory providers provides potential customer as disease-modifying therapy. 1,25(Oh yea)2D3-treated DC nor their capability to induce Capital t cell hyporesponsiveness. In addition, the Capital t cell hyporesponsiveness caused by 1,25(Oh yea)2D3-treated DC is definitely antigen-specific and powerful since Capital t cells maintain their capability to react to an unconnected antigen and perform not really reactivate upon rechallenge with completely mature standard DC, respectively. These findings underline the medical potential of tolerogenic DC (tolDC) to right the immunological. ...
RESEARCH AREA 2: The p15Paf oncogene. Specific recognition of MHC-peptide complexes results in extraordinary T cell proliferation, with doubling occurring approximately every 2-4 hours. Data from my lab suggested that a poorly characterized PCNA interacting protein, p15PAF, might play role a role in this rapid expansion of antigen specific T cells. Intriguingly, p15Paf, has also been shown to be substantially up-regulated in virtually every type of cancer and studies support that p15Paf is itself an oncogene. To determine the in vivo function of p15Paf in the immune system, my lab generated p15Paf deficient mice. Genetic disruption of p15Paf by homologous recombination resulted in altered hematopoietic stem cell (HSC) function and subsequent progenitor development, directly impacting the peripheral T and B cell compartments. Moreover, p15Paf controls the regulated proliferation of HSCs, keeping long-term-HSCs quiescent and protecting them from premature exhaustion. Our results also show that ...
Blood T-cells from 28 patients with type I (insulin-dependent) diabetes (IDDM) of variable duration were examined for the Tac antigen by immunofluorescence, and for proliferation in the presence of interleukin 2 (IL 2). The mean percentage of Tac+ cells in patients whose IDDM was of less than 2-yr duration was 6.2% compared with 2% in patients whose IDDM was of 3 or more years duration, or in healthy controls. The percentage of Tac+ cells in the patients blood correlated positively with the amount of thymidine uptake in a 24-h culture of blood mononuclear cells and with the percentage of T-cell blasts generated in a 6-day culture. The patients T-cell blasts stained with OKT 4 or OKT 8, suggesting that each of these subsets is present in the activated T-cell population in the patients blood. The T-cell blasts did not show specificity for pork insulin in an antigen restimulation assay. There was no correlation between increased Tac+ cells and the presence or absence of islet cell antibodies. ...
Programmed death-ligand 1 (PD-L1) also known as cluster of differentiation 274 (CD274) or B7 homolog 1 (B7-H1) is a protein that in humans is encoded by the CD274 gene. The formation of PD-1 receptor / PD-L1 or B7.1 receptor /PD-L1 ligand complex transmits an inhibitory signal which reduces the proliferation of these CD8+ T cells at the lymph nodes. Supplementary to that PD-1 is also able to control the accumulation of foreign antigen specific T cells in the lymph nodes through apoptosis which is further mediated by a lower regulation of the gene Bcl-2.
Cleveland Clinic The immune system has the potential to be a powerful tool to destroy tumors; however despite ample evidence of endogenous anti-tumor immune responses in many patients, as well as years of immunotherapy development, truly effective immune-based therapies remain out of reach. We have previously shown that co-incubation of normal human T cells with various tumor lines can induce dysfunctional changes in the T cells characterized by the loss of CD27/CD28 expression, hypo-proliferation upon activation, and the gain of suppressive function in vitro. We also found that this process could be inhibited by IL-7 signaling, primarily through PI3k/AKT signaling, and enhancing the expression of the pro-survival molecule Mcl-1. In the current study, we show that the process of tumor-induced dysfunction also induces the expression of PD-1 in both human and mouse T cells, and that tumor-exposed mouse T cells are also capable of suppressive function. We further show that the tumor ...
We all know how important is the immune system in our body. But what is the most important Immune System Function? Why is it that important for us?
In the present study, a multivariable analysis of the CD8+ T-cell response in mice vaccinated with different recombinant vaccines encoding the melanoma antigen TRP-2 delineated three main situations. The simplest finding involved the activity of the powerful rAd-hTRP-2 vaccine in prophylaxis of tumor challenge. All of the mice mounted a vigorous immune response against the mouse Kb-restricted epitope, as indicated by the significant changes in the number and functions of TRP-2-specific T lymphocytes. The immune response was so strong that correlation with the number of metastases was not feasible because the majority of the mice did not present countable metastases after challenge with B16 (7 of 10 mice had no metastases). T lymphocytes stimulated with the TRP-2180-188 peptide in vitro also recognized the wild-type melanoma. Nevertheless, it must be noted that prophylactic vaccination with the xenogeneic form of the antigen, although valuable for several experimental mouse tumor antigens, would ...
Jurkat cells are an immortalized T-lymphocyte cell line, treated with serial dilutions of staurosporine, camptothecin, and etoposide and then assay using Early Tox Live/Dead Assay Kit.
A type of T cell apoptosis that occurs towards the end of the expansion phase following the initial activation of mature T cells by antigen and is triggered by T cell receptor stimulation and signals transmitted via various surface-expressed members of th…
Results High expression of αEβ7 was noted on CD8+ and CD4+ Th9 cells, while α4β7 was expressed on CD8+, Th2 and Th17 cells. T cell receptor stimulation and transforming growth factor β were key inducers of αEβ7 on human T cells, while butyric acid suppressed αEβ7. In comparison to α4β7 blockade via vedolizumab, blockade of β7 via etrolizumab surrogate antibody superiorly reduced colonic numbers of CD8+ and Th9 cells in vivo after 3 hours, while no difference was noted after 0.5 hours. AEβ7 expression was higher on CD8+ T cells from patients with IBD under vedolizumab therapy. ...
Peripheral blood mononuclear cells (PBMC) will be collected from healthy volunteers and patients who present with different diseases that involve or implicate the immune system dysregulation (HIV infection, autoimmune diseases and cancer). These PBMC will be studied in vitro for a number of functional parameters, including generating soluable factors that inhibit HIV infection, developing patterns of immune dysregulation, and inducing apoptotic T cell death. The purpose of such studies is to obtain insight into the mechanisms of natural resistance to viral infections, AIDS pathogenesis, and disease-induced immune dysregulation ...
The killer, or cytotoxic, T lymphocytes can be identified in the laboratory by a surface molecule called CD8. Their function is to destroy body cells that
T cells are known to be plastic and to change their phenotype according to the cellular and biochemical milieu they are embedded in. In this study, we transposed this concept at a macroscopic level assessing whether changes in the environmental housing conditions of C57/BL6 mice would influence the phenotype and function of T cells. Our study shows that exposure to 2 weeks in an enriched environment (EE) does not impact the T cell repertoire in vivo and causes no changes in the early TCR-driven activation events of these cells. Surprisingly, however, T cells from enriched mice showed a unique T helper effector cell phenotype upon differentiation in vitro. This was featured by a significant reduction in their ability to produce IFN-γ and by an increased release of IL-10 and IL-17. Microarray analysis of these cells also revealed a unique gene fingerprint with key signaling pathways involved in autoimmunity being modulated. Together, our results provide first evidence for a specific effect of EE on T
l-Arginine is a versatile amino acid that plays a central role in the normal function of several organ systems including the immune system. Its availability is tightly controlled and varies significantly in different organs and tissues in the body. l-Arginine plays an important role in supporting T-cell proliferation. Its depletion in certain disease states results in a diminished T-cell response. The main purpose of this study was to determine the effect of the depletion of l-arginine on the expression of the T-cell receptor (TCR) proteins. When the helper T-cell line Jurkat was cultured in arginine-free medium, there was a preferential decrease in the expression of the TCR ζ chain (CD3ζ). The reduced expression of CD3ζ was observed within 24 h of culture in l-arginine-free medium and was completely reversed with the replenishment of l-arginine. Furthermore, the absence of l-arginine blocked the normal re-expression of the TCR that had been internalized after antigen stimulation. There also ...
Kanagawa, O.; Nakauchi, H.; Sekaly, R.P.; Maeda, K.; Takagaki, Y., 1990: Expression and function of the transfected CD8 alpha chain in murine T cell hybridomas
Creative Biolabs provides Anti-MCC peptide (ADLIAYLKQATK) T Cell Receptor (clone 226), Jurkat Cell Line product for Biopharmaceutical research,preclinical and clinical trials.
Introduction: CD137 (4-1BB) is a co-stimulatory molecule expressed by activated T and NK cells that, upon interaction with its CD137 ligand, further supports cell activation, proliferation and survival. Activation via CD137 holds great promise for cancer immunotherapy; however, current CD137 agonistic interventions are associated with systemic safety concerns. To develop a therapeutic modality that reduces the potential for systemic CD137 effects, we applied the DART® bispecific platform to generate proteins that can induce tumor-antigen dependent T-cell activation.. Methods: DART molecules were constructed containing anti-CD137 variable regions together with either anti-HER2 or anti-EphA2 variable regions. DART binding properties were evaluated by ELISA or flow cytometry; signaling responses assessed using a NF-κB luciferase reporter cell line expressing CD137. Co-stimulatory activity was characterized with primary human T cells in the presence or absence of tumor target antigen-expressing ...
T cells are produced in the thymus however precursor T cells are produced in the bone marrow and migrate to the thymus located in the mediastinum, once matured T cells will travel around the body. There are two types of T cells that derive from the thymus which can be distinguishable based on the molecules present on the cell surface. Helper T cells express a molecule called CD4 on their cell surface, therefore known as CD4 T cells (T helper cells). The other type of T cells express a molecule called CD8 on their cell surface, therefore known as CD8 T cells (known as cytotoxic after activation ...
Introduction. Recent research shows that programmed cell death has great importance in the pathomechanism of atherosclerosis. The BIRC5 and BIRC6 genes belong to Class III IAPs with the anti-apoptotic effect. The proteins display multidirectional action. According to the available literature, in addition to the effect of apoptosis inhibition they also display other properties. It is suggested that they play an important role in the processes of proliferation and cellular differentiation. Aim. The aim of the study was to assess the expression of the BIRC5 and BIRC6 genes in normal peripheral blood lymphocytes and in peripheral blood lymphocytes of patients diagnosed with atherosclerosis. Material and methods. The analysis was carried out on RNA samples obtained from peripheral blood lymphocytes of 21 patients with diagnosed atherosclerosis. The specific fragment of the analysed gene was obtained through amplification with the use of cDNA synthesised in the reaction of reverse transcription. The ...
Educational lecture on positive and negative selection, thymus, CD3+ γδ T-Cell, αβ Developmental Pathway, MHC restriction, differential-signaling and avidity hypothesis.
Construction of the T-cell receptor The antibody is not the only protein that recognizes the antigen. The antigen-specific receptor of T lymphocytes does the same. It is simply called the T-cell receptor and is abbreviated as the T-cell receptor TCR. We can define the antigen as a compound capable of eliciting the formation of a …. CELL IMMUNITY. T-CELL receptors (TCRs) and their epitopes Read More ». ...
The thymus is an evolutionarily ancient primary lymphoid organ common to all vertebrates in which T cell development takes place. Failing thymus function is associated with immunodeficiency and/or autoimmunity. In this volume, leading experts provide a comprehensive overview of recent advances in thymopoiesis research. The chapters cover the development of the thymic epithelial microenvironment, address the formation of a diverse and self-tolerant repertoire of T cell receptors as the basis for cellular immunity, discuss the mechanisms by which progenitor cells colonize the thymus and detail the molecular basis for T lineage decisions. The reviews illustrate the important role of the multifaceted process of thymopoiesis for adaptive immunity ...
Gentaur molecular products has all kinds of products like :search , Ray Biotech \ Mouse Anti-Mouse Major Histocompatability Complex Class I H-2Kb \ 129-10448 for more molecular products just contact us
TY - JOUR. T1 - Identification of alloreactive T-cell epitopes on the Rhesus D protein. AU - Stott, L M AU - Barker, R N AU - Urbaniak, S J PY - 2000. Y1 - 2000. N2 - Although considerable effort has been devoted to characterizing alloantibodies specific for the Rhesus D (RhD) blood group antigen, virtually nothing is known about the helper response that drives their production. Therefore, the aim of this study was to map alloreactive T-cell epitopes on the RhD protein. Peripheral blood mononuclear cells (PBMCs) were obtained from 22 RhD-negative volunteers in whom anti-D alloantibodies had developed after deliberate immunization or RhD-incompatible pregnancy, The PBMCs were stimulated with a panel of up to 68 overlapping synthetic 15-mer peptides Spanning the complete sequence of the RhD protein. One or more peptides elicited proliferative responses by PBMCs from all 22 of the alloimmune volunteers but from only 2 of 8 alloantibody-negative control donors. Proliferation of PBMCs from the ...
Physical stress induces a marked redistribution of T lymphocytes that may be influenced by carbohydrate (CHO) availability, yet the effect of these on T lymphocyte migration towards infected tissue is unknown. Therefore, the aim of this study was to determine the effect of strenuous exercise and CHO ingestion on subsequent ex vivo lymphocyte migration towards the supernatants of a Human Rhinovirus (HRV)-infected bronchial epithelial cell line. In a randomised, cross-over, double-blind design, 7 trained males ran for 2 h at 60% V . O2peak on two occasions with regular ingestion of either a 6.4% w/v glucose and maltodextrin solution (CHO trial) or placebo solution (PLA trial). Plasma glucose concentration was higher on CHO than PLA after exercise (P,0.05). Migration of CD4+ and CD8+ cells and their CD45RA+ and CD45RO+ subpopulations towards supernatants from HRV-infected cells decreased following exercise (main effect for exercise, P,0.01 for CD4+, CD4+CD45RA+ and CD4+CD45RO+; P,0.05 for CD8+, ...
Bacterial products such as toxins can interfere with a variety of cellular processes, leading to severe human diseases. Clostridium difficile toxins, TcdA and TcdB are the primary contributing factors to the pathogenesis of C. difficile-associated diseases (CDAD). While the mechanisms for TcdA and TcdB mediated cellular responses are complex, it has been shown that these toxins can alter chemotactic responses of neutrophils and intestinal epithelial cells leading to innate immune responses and tissue damages. The effects of C. difficile toxins on the migration and trafficking of other leukocyte subsets, such as T lymphocytes, are not clear and may have potential implications for adaptive immunity. We investigated here the direct and indirect effects of TcdA and TcdB on the migration of human blood T cells using conventional cell migration assays and microfluidic devices. It has been found that, although both toxins decrease T cell motility, only TcdA but not TcdB decreases T cell chemotaxis. Similar
The mechanism of T cell depletion during infection with the human immunodeficiency virus (HIV) is unclear. Examination of the repertoire of T cell receptor V (variable) regions in persons infected with HIV revealed the absence of a common set of V beta regions, whereas V alpha usage was normal. The lack of these V beta segments did not appear to correlate with opportunistic infections. The selective elimination of T cells that express a defined set of V beta sequences may indicate the presence of an HIV-encoded superantigen, similar to those encoded by the long terminal repeat of the mouse mammary tumor virus. ...
To investigate dynamic fluctuations of serum viral load and peripheral T-lymphocyte subpopulations of chronic hepatitis B patients and their correlation during entecavir therapy. Fifty-five patients received entecavir 0.5 mg/d therapy. Serum HBV DNA load was measured by Real-Time-PCR, and the levels of peripheral T-lymphocyte subpopulations by flow cytometry biweekly, every four weeks and every eight weeks during weeks 1-12, 13-24 and 24-48, respectively. Multilevel modelling was used to analyse the relationship between these variables. Of the 55 patients, all HBeAg positive and with detectable HBV DNA, the majority (81.8%) had serum levels of HBV DNA over 107 copies per milliliter. HBV viral load dropped sharply during the first two weeks. In 28 and 43 patients, the level became undetectable from week 24 and 48, respectively. Using pre-therapy level as the reference, a significant decrease in CD8+ T cells and increase in CD4+ T cells were found from week 12. Both parameters and CD4+/CD8+ ratio steadily
The ICOS-B7h costimulatory receptor-ligand pair is required for germinal center formation, the production of isotype-switched antibodies, and antibody affinity maturation in response to T cell-dependent antigens. However, the potentially distinct roles of regulated B7h expression on B cells and dendritic cells in T cell-dependent antibody responses have not been defined. We generated transgenic mice with lineage-restricted B7h expression to assess the cell-type specific roles of B7h expression on B cells and dendritic cells in regulating T cell-dependent antibody responses. Our results show that endogenous B7h expression is reduced on B cells after activation in vitro and is also reduced in vivo on antibody-secreting plasma B cells in comparison to both naïve and germinal center B cells from which they are derived. Increasing the level of B7h expression on activated and plasma B cells in B-B7hTg mice led to an increase in the number of antibody-secreting plasma cells generated after immunization and a
plus cbd oil spray For Auto Immune Disease, cbd oil spray cv sciences For Auto Immune Disease, plus cbd oil spray review For Auto Immune Disease, extra strength pluscbd oil spray For Auto Immune Disease, cbd oil spray For Auto Immune Disease, cbd oil spray peppermint 2 oz 500mg cbd For Auto Immune Disease, herbal renewals cbd oil spray For Auto Immune Disease, cbd hemp oil spray For Auto Immune Disease, spray lingual cbd cure oil extract 30ml For Auto Immune Disease, cbd oil spray for sale For Auto Immune Disease, cbd oil spray amazon For Auto Immune Disease, cbd oil spray dosage For Auto Immune Disease, cbd oil spray juice For Auto Immune Disease, cbd cure oil extract spray For Auto Immune Disease, plus cbd oil cbd spray tincture For Auto Immune Disease, how to use cbd oil spray For Auto Immune Disease, cbd oil spray jobs For Auto Immune Disease, cbd oil spray review For Auto Immune Disease, cbd oil spray for dogs For Auto Immune Disease, cbd oil extract spray For Auto Immune
Lymphocyte. Main article: Lymphocyte. Lymphocytes are much more common in the lymphatic system than in blood. Lymphocytes are ... Lymphocyte. 30%. Small lymphocytes 7-8. Large lymphocytes 12-15. *B cells: releases antibodies and assists activation of T ... lymphocytes) by hematopoietic lineage (cellular differentiation lineage).[6] Lymphocytes can be further classified as T cells, ... Lymphocytes include: *B cells make antibodies that can bind to pathogens, block pathogen invasion, activate the complement ...
A lymphoblast is a modified naive lymphocyte with altered cell morphology. It occurs when the lymphocyte is activated by an ... Lymphoblasts can also refer to immature cells which typically differentiate to form mature lymphocytes.[2] Normally ... Lymphoblasts look like immature lymphocytes, and were once thought to be precursor cells.".[4] Commonly, when speaking about ... The Chronic Lymphocytic Leukemia Research Consortium defines a lymphoblast as "A lymphocyte that has become larger after being ...
... granular lymphocytes known today as NK cells. The demonstration that density gradient-isolated large granular lymphocytes were ... Natural killer cells, or NK cells, are a type of cytotoxic lymphocyte critical to the innate immune system. The role NK cells ... A functional marker of human non-T lymphocytes". Clinical and Experimental Immunology. 21 (2): 226-35. PMC 1538269. PMID 810282 ... Large granular lymphocyte entry in the public domain NCI Dictionary of. *. Calmeiro J, Carrascal M, Gomes C, Falcão A, Cruz MT ...
These effects are primarily due to the loss of any helper T cell that can interact with the B lymphocyte correctly. Another ... Sallusto F, Lenig D, Förster R, Lipp M, Lanzavecchia A (1999). "Two subsets of memory T lymphocytes with distinct homing ... commonly lymphocytes and macrophages, resulting in chronic inflammation and cytokine release. Antibodies do not play a direct ... "Molecular interactions mediating T-B lymphocyte collaboration in human lymphoid follicles. Roles of T cell-B-cell-activating ...
A T cell, or T lymphocyte, is a type of lymphocyte (a subtype of white blood cell) that plays a central role in cell-mediated ... within a population of lymphocytes known as intraepithelial lymphocytes. In rabbits, sheep, and chickens, the number of γδ T ... T cells can be distinguished from other lymphocytes, such as B cells and natural killer cells, by the presence of a T-cell ... The T lymphocyte activation pathway: T cells contribute to immune defenses in two major ways; some direct and regulate immune ...
The Lymphocytes - represented by: *Lymphocytes B as marshals in small one-man round flying craft with two aimable side-mounted ... Lymphocytes T: the same sort of craft but with a large uppercase T on the underbelly at the bow. They can discharge smoke that ... Immature leucocytes: teenage humanoids with the same uniform as the lymphocyte B pilots: seen in the bone marrow, which is ... Captain Courageous and Ace for the lymphocyte B crafts' pilots; Plasmus and Globina for Hemo and Globin, Corpo for Jumbo; ...
Intraepithelial lymphocytes: distributed throughout the tissue.[4]. *Intraepithelial macrophages[5][6]. Stereocilia[edit]. The ...
Lymphocytes[change , change source]. Lymphocytes are round white blood cells a bit bigger than a red blood cell. Their center ... There are three known types of lymphocytes, called T-cells, B-cells, and natural killer cells (NK cells). ...
Peripheral blood lymphocytes. Normal Micronucleus test. Normal Heart weight. Normal Skin Histopathology. Normal ...
Peripheral blood lymphocytes. Normal Micronucleus test. Normal Heart weight. Normal Skin Histopathology. Normal ...
Peripheral blood lymphocytes. Normal. Micronucleus test. Normal. Heart weight. Normal. Brain histopathology. Normal. ...
Peripheral blood lymphocytes. Normal Heart weight. Normal Salmonella infection. Normal[8] Citrobacter infection. Normal[9] ...
The mantle zone (or just mantle) of a lymphatic nodule (or lymphatic follicle) is an outer ring of small lymphocytes ...
After recognizing an antigen, an antigen presenting cell such as the macrophage or B lymphocyte engulfs it completely by a ... or B lymphocytes) involving an arm of the immune system known as humoral immunity. The antibodies are soluble and do not ... The role of lymphocytes in mediating both cell-mediated and humoral responses was demonstrated by James Gowans in 1959.[30] ... What makes the analogy even stronger is that the B lymphocytes have to compete with each other for signals that promote their ...
Lymphocyte-rich. Is a rare subtype, show many features which may cause diagnostic confusion with nodular lymphocyte predominant ... Lymphocyte depleted. Is a rare subtype, composed of large numbers of often pleomorphic RS cells with only few reactive ... Nodular lymphocyte predominant Hodgkin's lymphoma expresses CD20, and is not currently considered a form of classical Hodgkin's ... Micrograph showing a "popcorn cell", the Reed-Sternberg cell variant seen in nodular lymphocyte predominant Hodgkin lymphoma. H ...
On T lymphocytesEdit. CD4+ T cells provide help to B cells that produce antibodies. Several subsets of activated effector CD4+ ... An Fc receptor is a protein found on the surface of certain cells - including, among others, B lymphocytes, follicular ... Pichler, W. J., Lum, L., and Broder, S. (1978) Fc-receptors on human T lymphocytes. I. Transition of Tgamma to Tmu cells. J ... Sandor, M., and Lynch, R. G. (1993) Lymphocyte Fc receptors: the special case of T cells. Immunology today 14, 227-231 10.1016/ ...
Necrosis is increased in T lymphocytes.. Tingible body macrophages (TBMs) - large phagocytic cells in the germinal centers of ... B and T cell tolerance for apoptotic cells is abrogated, and the lymphocytes get activated by these autoantigens; inflammation ... The cytokines B-lymphocyte stimulator (BLys), interleukin 6, interleukin 17, interleukin 18, type I interferons, and tumor ... The body's sensitized B-lymphocyte cells will now produce antibodies against these nuclear-related proteins. These antibodies ...
Reducing numbers of T-lymphocytes etc.. unknown. etanercept. decoy TNF receptor. bDMARD. ...
Association with p56lck in T lymphocytes". The Journal of Biological Chemistry. 271 (5): 2863-7. doi:10.1074/jbc.271.5.2863. ... CD44 participates in a wide variety of cellular functions including lymphocyte activation, recirculation and homing, ... "Lymphocyte CD44 binds the COOH-terminal heparin-binding domain of fibronectin". The Journal of Cell Biology. 116 (3): 817-25. ... protein tyrosine kinases Lck and Fyn in glycosphingolipid-rich plasma membrane domains of human peripheral blood lymphocytes". ...
In the 1960s, lymphocytes were discovered to be the mediators of allograft rejection in animals. Attempts to use T cells to ... Syngeneic lymphocytes were transferred from rodents heavily immunized against the tumor to inhibit growth of small established ... Description of T cell growth factor interleukin-2 (IL-2) in 1976 allowed T lymphocytes to be grown in vitro, often without loss ... The result is individually grown in IL-2. Lymphocytes overgrow. They destroy the tumors in the sample within 2 to 3 weeks. They ...
The B lymphocyte, in this ready-to-respond form, is known as a "naive B lymphocyte." The naive B lymphocyte expresses both ... Nemazee D (2006). "Receptor editing in lymphocyte development and central tolerance". Nat Rev Immunol. 6 (10): 728-740. doi: ... How Lymphocytes Produce Antibody from Cells Alive!. *Antibody applications Fluorescent antibody image library, University of ... Goding J (1978). "Allotypes of IgM and IgD receptors in the mouse: a probe for lymphocyte differentiation". Contemp Top ...
In the lymphatic system a lymph node is a secondary lymphoid organ.[1] Lymph nodes contain lymphocytes, a type of white blood ... In order to do this, lymph nodes contain lymphocytes, a type of white blood cell, which includes B cells and T cells. These ... Both B and T lymphocytes enter lymph nodes from circulating blood through specialized high endothelial venules found in the ... In the course of the lymph, lymphocytes may be activated as part of the adaptive immune response. ...
In a similar fashion, cytotoxic T lymphocytes patrol an area of skin and play an important role in controlling both the ... Their immunology centres on the interaction of immunoregulatory cytokines and discrete subpopulations of T lymphocytes. The ... and present the antigen to T-lymphocytes. This process is controlled by cytokines and chemokines - with tumor necrosis factor ... the differentiated DCs present the allergenic epitope associated with the allergen to T lymphocytes. These T cells then divide ...
The thymic cortex, mainly composed of lymphocytes; functions as a site for somatic recombination of T cell receptors, and ...
Associated organs composed of lymphoid tissue are the sites of lymphocyte production. Lymphocytes are concentrated in the lymph ... the spleen retains the ability to produce lymphocytes. The spleen stores red blood cells and lymphocytes. It can store enough ... The tertiary lymphoid tissue[clarification needed] typically contains far fewer lymphocytes, and assumes an immune role only ... The thymus is a primary lymphoid organ and the site of maturation for T cells, the lymphocytes of the adaptive immune system. ...
It is a rare genetic disorder of abnormal lymphocyte survival caused by defective Fas mediated apoptosis.[3] Normally, after ... Sirolimus may not be as immune suppressive in normal lymphocytes as other agents. Some patients have had improvement in immune ... Measured by flow cytometry: Normal values ,2.5% total T cells; ,1% of total lymphocytes in peripheral blood ... Fleisher, Thomas A. (2007). "The autoimmune lymphoproliferative syndrome: An experiment of nature involving lymphocyte ...
title = "Lymphocyte homing receptors",. author = "Hu, {M. C T} and Siegelman, {M. H.} and B. Holzmann and Crowe, {D. T.} and ... Lymphocyte homing receptors. / Hu, M. C T; Siegelman, M. H.; Holzmann, B.; Crowe, D. T.; Weissman, I. L. ... Hu, M. C T ; Siegelman, M. H. ; Holzmann, B. ; Crowe, D. T. ; Weissman, I. L. / Lymphocyte homing receptors. In: Cold Spring ... Hu, M. C. T., Siegelman, M. H., Holzmann, B., Crowe, D. T., & Weissman, I. L. (1992). Lymphocyte homing receptors. Cold Spring ...
... adrenaline and cytotoxic lymphocyte function, we re-assessed the role of cytotoxic lymphocytes in ME/CFS. Forty-eight patients ... adrenaline and cytotoxic lymphocyte function, we re-assessed the role of cytotoxic lymphocytes in ME/CFS. Forty-eight patients ... cytotoxicity lymphocyte aberrances were not found among ME/CFS patients. These assessments of cytotoxic lymphocytes therefore ... Cytotoxic lymphocytes combat intracellular infections. Their function is attenuated by stress. Despite numerous studies, the ...
A lymphocyte is one of the subtypes of a white blood cell in a vertebrates immune system. Lymphocytes include natural killer ... Tumor-infiltrating lymphocytes[edit]. Main article: Tumor-infiltrating lymphocyte. In some cancers, such as melanoma and ... A lymphocyte count is usually part of a peripheral complete blood cell count and is expressed as the percentage of lymphocytes ... The formation of lymphocytes is known as lymphopoiesis. B cells mature into B lymphocytes in the bursa equivalent, which in ...
Anti-lymphocyte globulin (ALG) is an infusion of animal- antibodies against human T cells which is used in the treatment of ... the latter of which was made by injecting horses with human thoracic duct lymphocytes and was called "Lymphoser Berna". Hakim, ...
Source for information on T Cells or T-Lymphocytes: World of Microbiology and Immunology dictionary. ... T cells or T-lymphocytes When a vertebrate encounters substances that are capable of causing it harm, a protective system known ... The T-8 lymphocytes differentiate into cytotoxic T-lymphocytes (CTLs) that can destroy the body cells that have the original ... T Cells or T-Lymphocytes. Updated About encyclopedia.com content Print Article Share Article ...
Negative co-receptors on lymphocytes.. Greenwald RJ1, Latchman YE, Sharpe AH. ...
Induced Division of Human Lymphocytes. Br Med J 1911; 1 doi: https://doi.org/10.1136/bmj.1.2614.284 (Published 04 February 1911 ...
Immunology of tumor infiltrating lymphocytes.. Holmes EC.. Abstract. Frequently peripheral blood lymphocytes (PBL) do not ... The tumor infiltrating lymphocytes (TIL) interact most closely with the tumor cells and are likely to more accurately reflect ...
T. Nitta and Y. Takahama, "The lymphocyte guard-IANs: regulation of lymphocyte survival by IAN/GIMAP family proteins," Trends ... S. J. McLeod and M. R. Gold, "Activation and function of the Rap1 GTPase in B lymphocytes," International Reviews of Immunology ... E. Genot and D. A. Cantrell, "Ras regulation and function in lymphocytes," Current Opinion in Immunology, vol. 12, no. 3, pp. ... P. Poussier, A. F. Nakhooda, J. A. Falk, C. Lee, and E. B. Marliss, "Lymphopenia and abnormal lymphocyte subsets in the "BB" ...
... or the presence of a high number of lymphocytes, can be caused by many different disorders and diseases, including ... What is the cause of having a high lymphocyte count in the blood?. A: A high lymphocyte count is referred to as lymphocytosis ... The Mayo Clinic asserts that the exact thresholds at which a high number of lymphocytes in a blood sample is considered to ... Children have much higher lymphocyte counts than adults, and the count tends to vary with age. In some cases, children must ...
Locally resident intraepithelial lymphocytes (IELs) are primarily T cells with potent cytolytic and immunoregulatory capacities ... Regulatory function for murine intraepithelial lymphocytes. Two subsets of CD3+, T cell receptor-1+ intraepithelial lymphocyte ... Intraepithelial lymphocytes traffic to the intestine and enhance resistance to Toxoplasma gondii oral infection. J. Immunol. ... Novel function for intestinal intraepithelial lymphocytes: murine CD3+, γ/δ TCR+ T cells produce IFN-γ and IL-5. J. Immunol. ...
Search for lymphocyte at other dictionaries: OneLook, Oxford, American Heritage, Merriam-Webster, Wikipedia. See lymphocyte ... Definitions of lymphocyte: *noun: an agranulocytic leukocyte that normally makes up a quarter of the white blood cell count but ...
T and B lymphocytes flow out from the arterial terminal, and migrate in the reticular framework. … Homing of lymphocytes to ... CD3+ and Pax5+ Lymphocytes in the Dermis of Normal Skin from the Dorsolateral Thorax of Cats [in Japanese] Fickle Daniel C. , ... Decreased Expression of MicroRNA-107 in B Lymphocytes of Patients with Antibody-Mediated Renal Allograft Rejection Zhang Zhe- ... mAb BW-3C3 react to a fraction of the lymphocytes. … The mAb-positive cells were identical to cells that also stained with ...
In the immune system such diverse cell types as T lymphocytes, B lymphocytes, macrophages, neutrophils, hybridomas, and natural ... In: Gupta S., Paul W.E. (eds) Mechanisms of Lymphocyte Activation and Immune Regulation II. Springer, Boston, MA. * DOI https ... Subset-specific expression of potassium channels in developing murine T lymphocytes. Science 239: 771 (1988).PubMedCrossRef ... Cahalan MD, Chandy KG, DeCoursey TE, Gupta S, Lewis R, Sutro JB: Ion channels in T lymphocytes. In: Gupta S, Paul WE, and Fauci ...
... a method for automatic counting of lymphocytes in histopathology images using connected components is presented. Our multi-step ... In this paper, a method for automatic counting of lymphocytes in histopathology images using connected components is presented ... Graf F., Grzegorzek M., Paulus D. (2010) Counting Lymphocytes in Histopathology Images Using Connected Components. In: Ünay D ... Application to lymphocyte segmentation on breast cancer histopathology. IEEE Transactions on Biomedical Engineering 57(7), 1676 ...
Lymphocyte 3.7 (L) Lymphocyte Absolute 0.6 (L) Absolute Neutrophil 14.9 (H) He has always been a super healthy kid. He seems to ... Lymphocyte 3.7 (L) Lymphocyte Absolute 0.6 (L) Absolute Neutrophil 14.9 (H) He has always been a super healthy kid. He seems to ... High WBC, Low lymphocytes. My 12yr old son had some blood work done in the ER, we were there due to some severe abdominal pain ... lymphocyte 0.25 - 0.33 mine is 0.25 my rbc is low what does this mean?? ive been diagnose of ptb ...
... turnover in lymphocytes since it is known that increased PI turnover is an early event induced by con A and other mitogenic ... colchicine also has been shown to inhibit con A-induced lymphocyte transformation at an early stage in the sequence of events ... con A inhibition of lymphocyte immunoglobulin receptor capping is reversed by colchicine2-4 and con A-induced aggregation of ... Colchicine inhibits phosphatidylinositol turnover induced in lymphocytes by concavalin A. *R. ROBERT SCHELLENBERG1. & ...
Lymphocyte definition, a type of white blood cell having a large, spherical nucleus surrounded by a thin layer of nongranular ... lymphocyte. Historical Examples. of lymphocyte. *. When large forms of the lymphocyte are present, the distinction is often ... Origin of lymphocyte. First recorded in 1885-90; lympho- + -cyte. Related formslym·pho·cyt·ic [lim-fuh-sit-ik] /ˌlɪm fəˈsɪt ɪk/ ... a type of white blood cell formed in lymphoid tissueSee also B-lymphocyte, T-lymphocyte ...
Description Monitoring lymphocyte counts in a patient with HIV infection is one way to assess the degree of immunosuppression ... CD4 lymphocytes act as the on switch for part of the immune system, so as the number of CD4 cells drops, damage to the immune ... Monitoring lymphocyte counts in a patient with HIV infection is one way to assess the degree of immunosuppression and the risk ... HIV infects and kills certain white blood cells called CD4 lymphocytes, reducing their number. The number of CD4 cells usually ...
Therefore, a large number of mutant T-lymphocytes with a person means that their owner has become a prey to irradiation or his/ ... Double increase of mutant lymphocyte frequency (more than 6.2 mutants per 10,000 cells) as compared to the background group was ... Increased frequency of mutations in patients lymphocytes is the evidence of risk. But, unfortunately, the lack of mutation ... Thus, European researchers have discovered that people with increased frequency of chromosomal abnormalities in lymphocytes of ...
T lymphocytes synonyms, T lymphocytes pronunciation, T lymphocytes translation, English dictionary definition of T lymphocytes ... n. Any of a class of lymphocytes, including the helper T cells and cytotoxic T lymphocytes, that form in bone marrow and mature ... Related to T lymphocytes: MHC, B lymphocytes, Cytotoxic T lymphocytes. T cell. n.. Any of a class of lymphocytes, including the ... T lymphocyte. lymph cell, lymphocyte - an agranulocytic leukocyte that normally makes up a quarter of the white blood cell ...
T. Diamond, "Review of Text-T Lymphocytes in the Liver," HPB Surgery, vol. 11, no. 6, pp. 421-421, 2000. https://doi.org/ ...
ROle of Apoptosis in Lymphocyte Depression (ROALD) - 03.23.17. Overview , Description , Applications , Operations , Results , ... ROle of Apoptosis in Lymphocyte Depression (ROALD) will to determine the role of programmed cell death (apoptosis) in loss of T ... lymphocyte activity in microgravity.. * Various aspects of the apoptotic process will be assessed, using human T-lymphocytes, ... In this project, we plan to ascertain whether or not Space conditions might induce apoptosis in human lymphocytes through a 5- ...
Lymphocytes are white blood cells whose function is to fight off infection. There are three major categories of lymphocytes: B- ... Significance of Low Lymphocytes Acquired from RA or Its Treatment. Abnormally low lymphocytes, or lymphocytopenia, presents ... RA can cause low lymphocytes. Lymphocytes, sometimes referred to as "fighter cells," attack infection-causing microorganisms. ... Lymphocytes are a vital component of the bodys immune system. Medical intervention may be necessary if the number of ...
Autologous Lymphocytes - A persons white blood cells. Lymphocytes have a number of roles in the immune system, including the ... Medical Word - Autologous Lymphocytes. Ans : A persons white blood cells. Lymphocytes have a number of roles in the immune ... Autologous Lymphocytes - Glossary. Written & Compiled by Medindia Content Team. Medically Reviewed by The Medindia Medical ...
  • A high lymphocyte count is referred to as lymphocytosis and is caused by a bacterial or viral infection, cancer, autoimmune disorders, tuberculosis, HIV/AI. (reference.com)
  • Monitoring lymphocyte counts in a patient with HIV infection is one way to assess the degree of immunosuppression and the risk of developing opportunistic infections. (healthcentral.com)
  • At 3 days postinfection, neither DEP exposure nor Listeria infection resulted in significant changes in T lymphocytes when compared with the air-exposed, noninfected control (data not shown). (thefreedictionary.com)
  • Lymphocytopenia, the medical term for a low number of lymphocytes circulating in the blood, places individuals at a high risk for infection. (ehow.co.uk)
  • is normal for a chronic hiv infection to have atipical lymphocytes (betewn 1-2%) 2. (thebody.com)
  • The atypical lymphocyte has more cytoplasm and thus grows larger in size than a normal lymphocyte as a reaction to infection, hormone production, radiation or other factors that influence the immune system. (wisegeek.com)
  • The shape, color and size of the lymphocyte can offer lab pathologists the opportunity to identify the source of the infection. (wisegeek.com)
  • An increase in lymphocyte concentration is usually a sign of a viral infection (in some rare case, leukemias are found through an abnormally high lymphocyte count in an otherwise normal person). (wikipedia.org)
  • Mature lymphocytes recirculate via blood and lymph through lymphoid tissues in a relatively quiescent state until stimulated to proliferate during, for example, a bacterial or viral infection. (scielo.br)
  • Microscopically, in a Wright's stained peripheral blood smear , a normal lymphocyte has a large, dark-staining nucleus with little to no eosinophilic cytoplasm. (wikipedia.org)
  • Crowding by the surrounding red blood cell is the reason why the lymphocytes produced by infectious mononucleosis often have a dented shape to their cytoplasm. (wisegeek.com)
  • Most of the lymphocytes in peripheral blood are small with scanty nongranular cytoplasm and a central nucleus with coarse chromatin. (hubpages.com)
  • Chandy KG, DeCoursey TE, Fischbach M, Talal N, Cahalan MD, Gupta S: Altered K+ channel expression in abnormal T lymphocytes from mice with the 1pr gene mutation. (springer.com)
  • Although lymphocytes are always present in the bloodstream, interaction with immune system triggers is required to create an environment in which the abnormal lymphocyte is produced. (wisegeek.com)
  • These defining characteristics are not always available, but some pathogens regularly cause abnormal lymphocytes to form specific characteristics. (wisegeek.com)
  • Anti-immunoglobulin stimulation of B lymphocytes activates src-related protein-tyrosine kinases. (pnas.org)
  • Klein, J. R. Ontogeny of the Thy-1-, Lyt-2 + murine intestinal intraepithelial lymphocyte. (nature.com)
  • DeCoursey TE, Chandy KG, Gupta S, Cahalan MD: Two types of potassium channels in murine T lymphocytes. (springer.com)
  • DeCoursey TE, Chandy KG, Gupta S, Cahalan MD: Mitogen induction of ion channels in murine T lymphocytes. (springer.com)
  • Lewis RS and Cahalan MD. Subset-specific expression of potassium channels in developing murine T lymphocytes. (springer.com)
  • These results suggest that the mitogenesis of murine T lymphocytes is triggered by the activation of both phospholipid methyltransferase(s) and phospholipase A2. (pnas.org)
  • T-helper cell type (Th)2 lymphocytes play an important role in the initiation, progression and persistence of allergic diseases, including asthma. (ersjournals.com)
  • In contrast to strictly cytokine-producing helper ILCs, resident innate lymphocyte populations with cytolytic potential have been identified in multiple tissues in both mouse and human. (jimmunol.org)
  • HealthCentral explains that lymphocytosis, or the presence of a high number of lymphocytes, can be caused by many different disorders and diseases, including mononucleosis, toxoplasmosis, AIDS and tuberculosis. (reference.com)
  • According to Japanese and Russian researchers' data, the patients suffering from larynx cancer and some other malignant growths, even before treatment starts experience increase of quantity of lymphocytes with T-cell receptor (TCR) genes mutations. (innovations-report.com)
  • Detection of gene expression specific for different kind of immune cell populations can then be used to determine the degree of lymphocyte infiltration as has been shown in breast cancer. (wikipedia.org)
  • A drastic reduction of lymphocytes can lead to persistent infections from fungi, bacteria and viruses. (ehow.co.uk)
  • Lymphocytes are different from the other WBCs because they can recognize and have a memory of invading bacteria and viruses . (howstuffworks.com)