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.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.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.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.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.Antigens: Substances that are recognized by the immune system and induce an immune reaction.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.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.Antibodies, Monoclonal: Antibodies produced by a single clone of cells.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.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.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.Interleukin-2: A soluble substance elaborated by antigen- or mitogen-stimulated T-LYMPHOCYTES which induces DNA synthesis in naive lymphocytes.Antigens, 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.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.Antigens, Bacterial: Substances elaborated by bacteria that have antigenic activity.Helper Viruses: Viruses which enable defective viruses to replicate or to form a protein coat by complementing the missing gene function of the defective (satellite) virus. Helper and satellite may be of the same or different genus.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.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.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)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.Immunoenzyme Techniques: Immunologic techniques based on the use of: (1) enzyme-antibody conjugates; (2) enzyme-antigen conjugates; (3) antienzyme antibody followed by its homologous enzyme; or (4) enzyme-antienzyme complexes. These are used histologically for visualizing or labeling tissue specimens.Antigens, Viral: Substances elaborated by viruses that have antigenic activity.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.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.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.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.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.Spleen: An encapsulated lymphatic organ through which venous blood filters.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.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).Mice, Inbred BALB CCD8-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.Mice, Inbred C57BLFlow 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.H-2 Antigens: The major group of transplantation antigens in the mouse.Epitopes: Sites on an antigen that interact with specific antibodies.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.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.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.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.Cell Line: Established cell cultures that have the potential to propagate indefinitely.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.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.Antigens, Protozoan: Any part or derivative of any protozoan that elicits immunity; malaria (Plasmodium) and trypanosome antigens are presently the most frequently encountered.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.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.Antigens, Polyomavirus Transforming: Polyomavirus antigens which cause infection and cellular transformation. The large T antigen is necessary for the initiation of viral DNA synthesis, repression of transcription of the early region and is responsible in conjunction with the middle T antigen for the transformation of primary cells. Small T antigen is necessary for the completion of the productive infection cycle.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.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.Concanavalin 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.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.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.Antibody Formation: The production of ANTIBODIES by proliferating and differentiated B-LYMPHOCYTES under stimulation by ANTIGENS.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.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.Immunoglobulin G: The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of IgG, for example, IgG1, IgG2A, and IgG2B.Antigens, Fungal: Substances of fungal origin that have antigenic activity.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.Lymph Nodes: They are oval or bean shaped bodies (1 - 30 mm in diameter) located along the lymphatic system.Antigens, Helminth: Any part or derivative of a helminth that elicits an immune reaction. The most commonly seen helminth antigens are those of the schistosomes.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).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.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.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.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.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.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.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.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.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.Cell Differentiation: Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.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).Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.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.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.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.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.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.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.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.Membrane Glycoproteins: Glycoproteins found on the membrane or surface of cells.Cell SeparationEpitopes, 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.Lymphocyte Cooperation: T-cell enhancement of the B-cell response to thymic-dependent antigens.Carcinoembryonic Antigen: A glycoprotein that is secreted into the luminal surface of the epithelia in the gastrointestinal tract. It is found in the feces and pancreaticobiliary secretions and is used to monitor the response to colon cancer treatment.Cell Division: The fission of a CELL. It includes CYTOKINESIS, when the CYTOPLASM of a cell is divided, and CELL NUCLEUS DIVISION.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.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.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)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.Antigens, Viral, Tumor: Those proteins recognized by antibodies from serum of animals bearing tumors induced by viruses; these proteins are presumably coded for by the nucleic acids of the same viruses that caused the neoplastic transformation.Lymphocyte Transfusion: The transfer of lymphocytes from a donor to a recipient or reinfusion to the donor.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.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.Cross Reactions: Serological reactions in which an antiserum against one antigen reacts with a non-identical but closely related antigen.Mice, Transgenic: Laboratory mice that have been produced from a genetically manipulated EGG or EMBRYO, MAMMALIAN.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.)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.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.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.Antibody Specificity: The property of antibodies which enables them to react with some ANTIGENIC DETERMINANTS and not with others. Specificity is dependent on chemical composition, physical forces, and molecular structure at the binding site.Time Factors: Elements of limited time intervals, contributing to particular results or situations.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.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.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.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).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.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.Antigen-Antibody Reactions: The processes triggered by interactions of ANTIBODIES with their ANTIGENS.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.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.Recombinant Proteins: Proteins prepared by recombinant DNA technology.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.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.Ovalbumin: An albumin obtained from the white of eggs. It is a member of the serpin superfamily.Lymphocyte 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.Hypersensitivity, Delayed: An increased reactivity to specific antigens mediated not by antibodies but by cells.Immune Sera: Serum that contains antibodies. It is obtained from an animal that has been immunized either by ANTIGEN injection or infection with microorganisms containing the antigen.Proliferating Cell Nuclear Antigen: Nuclear antigen with a role in DNA synthesis, DNA repair, and cell cycle progression. PCNA is required for the coordinated synthesis of both leading and lagging strands at the replication fork during DNA replication. PCNA expression correlates with the proliferation activity of several malignant and non-malignant cell types.Mice, Inbred C3HReceptors, 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.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.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.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.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).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.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.Mice, Inbred CBAAntigens, CD80: A costimulatory ligand expressed by ANTIGEN-PRESENTING CELLS that binds to CTLA-4 ANTIGEN with high specificity and to CD28 ANTIGEN with low specificity. The interaction of CD80 with CD28 ANTIGEN provides a costimulatory signal to T-LYMPHOCYTES, while its interaction with CTLA-4 ANTIGEN may play a role in inducing PERIPHERAL TOLERANCE.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.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, CD15: A trisaccharide antigen expressed on glycolipids and many cell-surface glycoproteins. In the blood the antigen is found on the surface of NEUTROPHILS; EOSINOPHILS; and MONOCYTES. In addition, CD15 antigen is a stage-specific embryonic antigen.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)HLA-D Antigens: Human immune-response or Class II antigens found mainly, but not exclusively, on B-lymphocytes and produced from genes of the HLA-D locus. They are extremely polymorphic families of glycopeptides, each consisting of two chains, alpha and beta. This group of antigens includes the -DR, -DQ and -DP designations, of which HLA-DR is most studied; some of these glycoproteins are associated with certain diseases, possibly of immune etiology.MART-1 Antigen: A melanosome-specific protein that plays a role in the expression, stability, trafficking, and processing of GP100 MELANOMA ANTIGEN, which is critical to the formation of Stage II MELANOSOMES. The protein is used as an antigen marker for MELANOMA cells.Receptors, Antigen: Molecules on the surface of B- and T-lymphocytes that recognize and combine with specific antigens.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.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.Prostate-Specific Antigen: A glycoprotein that is a kallikrein-like serine proteinase and an esterase, produced by epithelial cells of both normal and malignant prostate tissue. It is an important marker for the diagnosis of prostate cancer.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.O Antigens: The lipopolysaccharide-protein somatic antigens, usually from gram-negative bacteria, important in the serological classification of enteric bacilli. The O-specific chains determine the specificity of the O antigens of a given serotype. O antigens are the immunodominant part of the lipopolysaccharide molecule in the intact bacterial cell. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)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)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.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Antigens, CD19: Differentiation antigens expressed on B-lymphocytes and B-cell precursors. They are involved in regulation of B-cell proliferation.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.Antigens, CD1: Glycoproteins expressed on cortical thymocytes and on some dendritic cells and B-cells. Their structure is similar to that of MHC Class I and their function has been postulated as similar also. CD1 antigens are highly specific markers for human LANGERHANS CELLS.Hepatitis B Surface Antigens: Those hepatitis B antigens found on the surface of the Dane particle and on the 20 nm spherical and tubular particles. Several subspecificities of the surface antigen are known. These were formerly called the Australia antigen.Antigens, Tumor-Associated, Carbohydrate: Carbohydrate antigens expressed by malignant tissue. They are useful as tumor markers and are measured in the serum by means of a radioimmunoassay employing monoclonal antibodies.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.Gene Expression: The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.Leukemia, Lymphoid: Leukemia associated with HYPERPLASIA of the lymphoid tissues and increased numbers of circulating malignant LYMPHOCYTES and lymphoblasts.Antigens, CD40: A member of the tumor necrosis factor receptor superfamily with specificity for CD40 LIGAND. It is found on mature B-LYMPHOCYTES and some EPITHELIAL CELLS, lymphoid DENDRITIC CELLS. Evidence suggests that CD40-dependent activation of B-cells is important for generation of memory B-cells within the germinal centers. Mutations of the gene for CD40 antigen result in HYPER-IGM IMMUNODEFICIENCY SYNDROME, TYPE 3. Signaling of the receptor occurs through its association with TNF RECEPTOR-ASSOCIATED FACTORS.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.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.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.Virus 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.Haptens: Small antigenic determinants capable of eliciting an immune response only when coupled to a carrier. Haptens bind to antibodies but by themselves cannot elicit an antibody response.HLA-B Antigens: Class I human histocompatibility (HLA) surface antigens encoded by more than 30 detectable alleles on locus B of the HLA complex, the most polymorphic of all the HLA specificities. Several of these antigens (e.g., HLA-B27, -B7, -B8) are strongly associated with predisposition to rheumatoid and other autoimmune disorders. Like other class I HLA determinants, they are involved in the cellular immune reactivity of cytolytic T lymphocytes.HIV Antigens: Antigens associated with specific proteins of the human adult T-cell immunodeficiency virus (HIV); also called HTLV-III-associated and lymphadenopathy-associated virus (LAV) antigens.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).Hemolytic Plaque Technique: A method to identify and enumerate cells that are synthesizing ANTIBODIES against ANTIGENS or HAPTENS conjugated to sheep RED BLOOD CELLS. The sheep red blood cells surrounding cells secreting antibody are lysed by added COMPLEMENT producing a clear zone of HEMOLYSIS. (From Illustrated Dictionary of Immunology, 3rd ed)Lymphocytes, Null: A class of lymphocytes characterized by the lack of surface markers specific for either T or B lymphocytes.Peptide Fragments: Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.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.Antibodies, Viral: Immunoglobulins produced in response to VIRAL ANTIGENS.H-Y Antigen: A sex-specific cell surface antigen produced by the sex-determining gene of the Y chromosome in mammals. It causes syngeneic grafts from males to females to be rejected and interacts with somatic elements of the embryologic undifferentiated gonad to produce testicular organogenesis.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.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.HemocyaninHerpesvirus 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.Antigens, Thy-1: A group of differentiation surface antigens, among the first to be discovered on thymocytes and T-lymphocytes. Originally identified in the mouse, they are also found in other species including humans, and are expressed on brain neurons and other cells.Isoantigens: Antigens that exist in alternative (allelic) forms in a single species. When an isoantigen is encountered by species members who lack it, an immune response is induced. Typical isoantigens are the BLOOD GROUP ANTIGENS.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.Cell Proliferation: All of the processes involved in increasing CELL NUMBER including CELL DIVISION.Autoantigens: Endogenous tissue constituents that have the ability to interact with AUTOANTIBODIES and cause an immune response.Cell Adhesion: Adherence of cells to surfaces or to other cells.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.Kinetics: The rate dynamics in chemical or physical systems.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).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)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.Cancer Vaccines: Vaccines or candidate vaccines designed to prevent or treat cancer. Vaccines are produced using the patient's own whole tumor cells as the source of antigens, or using tumor-specific antigens, often recombinantly produced.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.Immunization, Passive: Transfer of immunity from immunized to non-immune host by administration of serum antibodies, or transplantation of lymphocytes (ADOPTIVE TRANSFER).Blood Group Antigens: Sets of cell surface antigens located on BLOOD CELLS. They are usually membrane GLYCOPROTEINS or GLYCOLIPIDS that are antigenically distinguished by their carbohydrate moieties.Mice, Inbred DBAPolymerase 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.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.Hybridomas: Cells artificially created by fusion of activated lymphocytes with neoplastic cells. The resulting hybrid cells are cloned and produce pure MONOCLONAL ANTIBODIES or T-cell products, identical to those produced by the immunologically competent parent cell.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.Recombinant Fusion Proteins: Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.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.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.Antibodies, Bacterial: Immunoglobulins produced in a response to BACTERIAL ANTIGENS.Leukocytes: White blood cells. These include granular leukocytes (BASOPHILS; EOSINOPHILS; and NEUTROPHILS) as well as non-granular leukocytes (LYMPHOCYTES and MONOCYTES).Molecular Weight: The sum of the weight of all the atoms in a molecule.Antigens, CD86: A costimulatory ligand expressed by ANTIGEN-PRESENTING CELLS that binds to CD28 ANTIGEN with high specificity and to CTLA-4 ANTIGEN with low specificity. The interaction of CD86 with CD28 ANTIGEN provides a stimulatory signal to T-LYMPHOCYTES, while its interaction with CTLA-4 ANTIGEN may play a role in inducing PERIPHERAL TOLERANCE.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.
... s include both inducer/helper functions (Inducer Factors) and regulator functions (Regulator Factors)- ... This lymphocyte product is sometimes referred to as "dialyzable leukocyte extract" in the scientific literature due to being an ... Henry Sherwood Lawrence discovered that blood cells could 'transfer' antigen-specific cell-mediated immunity even after the ... immunized against an antigen could transfer immunity when injected into Guinea pigs that had never been exposed to the antigen ...
ILCs, on the contrary, may set the helper T lymphocytes in the state of anergy. In the case of ILC 3, the ability to express ... "Lymphoid tissue inducer-like cells are an innate source of IL-17 and IL-22." Journal of Experimental Medicine 206.1 (2009): 35- ... ILC 3 can express MHC II and be appropriating the function of antigen presenting cells. However, ILCs lack the costimulatory ... They produce cytokines typical for the population of Th17 helper lymphocytes. The characteristic feature of ILC 3 is the ...
Support is lent to this idea by the observation that a receptor for IL-12 is important for IFNγ production by lymphocytes. T ... Interleukin 12 (IL-12) is produced by activated antigen-presenting cells (dendritic cells, macrophages). It promotes the ... promote type 2 cytokine production in maturing human naive T helper cells". J. Immunol. 159 (1): 28-35. PMID 9200435. Hsieh CS ... development of Th1 responses and is a powerful inducer of IFNγ production by T and NK cells. A child with Bacillus Calmette- ...
Lymphoid tissue inducer ('LTi') cells are a subset of ILCs expressing molecules required for the development of lymphoid tissue ... Group 2 ILCs can produce type 2 cytokines (e.g. IL-4, IL-5, IL-9, IL-13). ILC2s (also termed natural helper cells, nuocytes, or ... These cells are defined by absence of antigen specific B or T cell receptor because of the lack of recombination activating ... Leavy, Olive (25 January 2013). "Innate-like lymphocytes: Will the real ILC1 please stand up?". Nature Reviews Immunology. 13 ( ...
... and by others as a product of antigen-stimulated lymphocytes or tuberculin-sensitized mouse peritoneal lymphocytes challenged ... and presentation of antigens from those pathogens. Next the Th1 helper cells aggregate around the macrophages and release IFNγ ... IFNγ is an important activator of macrophages and inducer of Class II major histocompatibility complex (MHC) molecule ... and by CD4 Th1 and CD8 cytotoxic T lymphocyte (CTL) effector T cells once antigen-specific immunity develops. IFNγ is also ...
FDCs assist the development of the germinal center via an interaction with B lymphocytes and helper T-lymphocytes. B ... Antigen-presenting cells accumulate near high endothelial venules to process soluble antigens. Antigens are also presented on ... Crosstalk LEC, lymphoid tissue inducer cells and mesenchymal stromal organizer cells initiate the formation of lymph nodes. ... Naive lymphocytes (those with no history of contact with antigens) travel from the bone marrow or high endothelial venules of ...
Tumor-reactive antigen-specific CTL generated by priming in the presence of IL-21 led to a stable, 'helper-independent' ... Dose-limiting toxicities included low lymphocyte, neutrophil, and thrombocyte count as well as hepatotoxicity. According to the ... a novel inducer of Blimp-1 and Bcl-6". J. Immunol. 173 (9): 5361-71. doi:10.4049/jimmunol.173.9.5361. PMID 15494482. Mehta DS, ... In addition, IL-21 expression is up-regulated in Th2 and Th17 subsets of T helper cells, as well as T follicular cells. ...
Antigen Antigenicity Immunogen Superantigen Allergen Hapten Epitope Linear Conformational Mimotope Tumor antigen Antigen- ... Follicular helper T cells Cytotoxic T cells - Commonly termed CD8+ T cells Memory T cells Regulatory T cells Natural Killer T ... Group 2 ILC Nuocyte Group 3 ILC Lymphoid Tissue inducer cells (LTi cells) (Non-hematopoietic cells with immune functions) ... SLAMF9 Cadherins Selectins E-selectin L-selectin P-selectin Others Lymphocyte homing receptors CD34 GLYCAM-1 Addressin (MAdCAM- ...
2004). "Endothelial monocyte-activating polypeptide-II (EMAP-II): a novel inducer of lymphocyte apoptosis". J. Leukoc. Biol. 75 ... The protein encoded by this gene is a cytokine that may be induced by apoptosis and is also released from professional antigen- ... As an inflammatory cytokine, AIMp1/p43 has demonstrated the ability to skew T-helper polarization in the direction of Th-1, and ... 2004). "Colorectal cancer cells induce lymphocyte apoptosis by an endothelial monocyte-activating polypeptide-II-dependent ...
These effects are primarily due to the loss of any helper T cell that can interact with the B lymphocyte correctly. Another ... For example, when an antigen-presenting cell expresses an antigen on MHC class II, a CD4+ cell will aid those cells through a ... which makes them less susceptible to some inducers of cell death. While we know about the types of cytokine patterns helper T ... Th17 helper cells are a subset of T helper cells developmentally distinct from Th1 and Th2 lineages producing interleukin 17 ( ...
An antigen is ingested and processed by an APC. It presents fragments from it to T cells. The upper, Th0, is a T helper cell. ... These effects are primarily due to the loss of any helper T cell that can interact with the B lymphocyte correctly. Another ... which makes them less susceptible to some inducers of cell death.[11][12] ... Main article: T helper 17 cell. Th17 helper cells are a subset of T helper cells developmentally distinct from Th1 and Th2 ...
... and by others as a product of antigen-stimulated lymphocytes[6][7] or tuberculin-sensitized mouse peritoneal lymphocytes[8] ... and presentation of antigens from those pathogens. Next the Th1 helper cells aggregate around the macrophages and release IFNγ ... IFNγ is an important activator of macrophages and inducer of Class II major histocompatibility complex (MHC) molecule ... and by CD4 Th1 and CD8 cytotoxic T lymphocyte (CTL) effector T cells once antigen-specific immunity develops.[11][12] IFNγ is ...
Monoclonal antibodies to T-helper/inducer and T-suppressor/cytotoxic lymphocyte subsets recognize antigens on splenic ... Monoclonal antibodies to T-helper/inducer and T-suppressor/cytotoxic lymphocyte subsets recognize antigens on splenic ... MoAbs to the helper/inducer and suppressor/cytotoxic subsets of T-lymphocytes do not appear to identify Ags unique to these ... In addition to recognizing lymphocytes in the T-zone (periarteriolar lymphoid sheaths), MoAbs to the helper/inducer and ...
... generally requires the participation of CD4+ T-helper lymphocytes, the nature of the help provided to CTLs is unknown. One ... widely held view is that help for CTLs is mediated by cytokines produced by T-helper cells activated in proximi … ... Although in vivo priming of CD8+ cytotoxic T lymphocytes (CTLs) ... Helper-Inducer / immunology Substances * CD40 Antigens * ... Although in vivo priming of CD8+ cytotoxic T lymphocytes (CTLs) generally requires the participation of CD4+ T-helper ...
... thereby inhibiting the activation of helper T cells. Using these drugs as probes, chemists and biologists have uncovered ... T-Lymphocytes / immunology * T-Lymphocytes, Helper-Inducer / immunology * Tacrolimus / chemistry * Tacrolimus / immunology* ... Receptors, Antigen, T-Cell / immunology * Signal Transduction / immunology* * ... thereby inhibiting the activation of helper T cells. Using these drugs as probes, chemists and biologists have uncovered ...
Antigens, Differentiation, T-Lymphocyte. *Carcinoma, Non-Small-Cell Lung. *T-Lymphocytes, Helper-Inducer ...
... antibody specific for surface antigen present on helper/inducer T lymphocytes; e. antibody specific for surface antigen present ... wherein the antibodies specific for antigens present on T lymphocytes, helper/inducer T lymphocytes and suppressor/cytotoxic T ... helper/inducer T lymphocytes and suppressor/cytotoxic T lymphocytes; (iii) walls extending upwardly from the support surface ... It infects and destroys the CD4 antigen positive (CD4+) helper/inducer T cells, an important subpopulation of immunocytes ...
It is expressed on T-helper/inducer lymphocytes and monocytes. CD3+CD4+ T cells comprise approximately 28% to 58% of normal ... L3T4, Leu3a, T-cell surface antigen T4/Leu-3, W3/25, CD4 antigen (p55). ... The CD4 antigen is present in low density on the cell surface of monocytes and in the cytoplasm of monocytes and macrophages ( ... The CD4 antigen is a 55 kDa type 1 transmembrane glycoprotein that belongs to the immunoglobulin superfamily. ...
Antigens, Cd4. 55-kDa antigens found on HELPER-INDUCER T-LYMPHOCYTES and on a variety of other immune cell types. CD4 antigens ... Cd4 Antigens. 55-kDa antigens found on HELPER-INDUCER T-LYMPHOCYTES and on a variety of other immune cell types. They are ... On T-lymphocytes they define the helper/inducer subset. T4 antigens also serve as INTERLEUKIN-15 receptors and bind to the HIV ... On T-lymphocytes they define the helper/inducer subset. CD4 antigens also serve as INTERLEUKIN-15 receptors and bind to the HIV ...
55-kDa antigens found on HELPER-INDUCER T-LYMPHOCYTES and on a variety of other immune cell types. CD4 antigens are members of ... On T-lymphocytes they define the helper/inducer subset. CD4 antigens also serve as INTERLEUKIN-15 receptors and bind to the HIV ... CD4 Antigens (CD4 Antigen). Subscribe to New Research on CD4 Antigens 55-kDa antigens found on HELPER-INDUCER T-LYMPHOCYTES and ... Antigens: 114404*Surface Antigens: 4354*Differentiation Antigens: 1051*CD Antigens: 38*CD4 Antigens: 230*recombinant soluble ...
... , Lymphocyte, B-Lymphocyte, B-Cell, T-Lymphocyte, T-Cell, Natural Killer Cell, NK cell, Lymphocytosis. ... Two types have been identified - cytotoxic (T-LYMPHOCYTES, CYTOTOXIC) and helper T-lymphocytes (T-LYMPHOCYTES, HELPER-INDUCER ... Antigen binds B-Lymphocyte Surface Receptor (BCR). *BCR binding activates B-Lymphocyte. *T-Cell Independent Antigen (e.g. inert ... t lymphocyte, t cells, t lymphocytes, t-lymphocytes, t-lymphocyte, t-cell, T Cell Lymphocyte, T lymphocyte, T cell, T-cell, T ...
... , Lymphocyte, B-Lymphocyte, T-Lymphocyte, Natural Killer Cell, Lymphocytosis. ... Two types have been identified - cytotoxic (T-LYMPHOCYTES, CYTOTOXIC) and helper T-lymphocytes (T-LYMPHOCYTES, HELPER-INDUCER ... When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen. ... Lymphocyte Count. Lymphocyte Count Aka: Lymphocyte Count, Lymphocyte, B-Lymphocyte, T-Lymphocyte, Natural Killer Cell, ...
An ultrastructural study on the lymphocytes from peripheral blood samples from 20 healthy adult Arabian oryx (Oryx leucocoryx) ... Two types have been identified - cytotoxic (T-LYMPHOCYTES, CYTOTOXIC) and helper T-lymphocytes (T-LYMPHOCYTES, HELPER-INDUCER ... Removal, via CELL DEATH, of immature lymphocytes that interact with antigens during maturation. For T-lymphocytes this occurs ... Lymphocytes, Null. A class of lymphocytes characterized by the lack of surface markers specific for either T or B lymphocytes. ...
Two types have been identified - cytotoxic (T-LYMPHOCYTES, CYTOTOXIC) and helper T-lymphocytes (T-LYMPHOCYTES, HELPER- INDUCER ... When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen. MeSH, 1990 ... T Helper: The T helper cells (Th cells) are a type of T cell that play an important role in the immune system, particularly in ... T Cell: A T cell, or T lymphocyte, is a type of lymphocyte (a subtype of white blood cell) that plays a central role in cell- ...
T helper 1 (Th1) lymphocytes are potent inducers of inflammation. This has been demonstrated by adoptive transfer of Th1 ... T helper 1 and T helper 2 cells are pathogenic in an antigen-specific model of colitis. J. Exp. Med. 195:71-84. ... The CD27- subset of peripheral blood memory CD4+ lymphocytes contains functionally differentiated T lymphocytes that develop by ... which were activated with antigen once or repeatedly at 6-d intervals. Naive CD4+CD62Lhi T lymphocytes expressing the ...
... are considered to function as helpers/inducers through the release of lymphokines when stimulated by a specific antigen; ... Large numbers of lymphocytes were used to overcome the presumed low frequency of precursors. Generation of CD8+ CTL responses ... The binding of immunogenic peptides to class II MHC antigens most commonly occurs for antigens ingested by antigen presenting ... When unlabeled, the antigen find use in agglutination assays. In addition, unlabeled antigen can be used in combination with ...
CD4 is expressed on T-helper/inducer lymphocytes and monocytes. BD Horizon™ BV480 Mouse Anti-Human CD4 serves as a T cell ... coreceptor for MHC class II antigen recognition and as a receptor for the human immunodeficiency virus (HIV). The SK3 antibody ...
CD4+ T-lymphocytes (helper T cells) and CD8+ T cells (suppressor/inducer T cells ... During incubation, if HIV-1 antibodies are present in the specimen, they will bind to the viral antigens bound to the ... CD4+ T-lymphocytes (helper T cells) and CD8+ T cells (suppressor/inducer T cells ... CD4+ T cells (helper T cells) and CD8+ T cells (suppressor/inducer T cells) ...
Isolation and Th17 Differentiation of Naïve CD4 T Lymphocytes, Application of Long-term cultured Interferon-γ Enzyme-linked ... Murine Lymphocyte Labeling by 64Cu-Antibody Receptor Targeting for In Vivo Cell Trafficking by PET/CT, Imaging CD4 T Cell ... Th1 Cells: Subset of helper-inducer T-lymphocytes which synthesize and secrete interleukin-2, gamma-interferon, and interleukin ... Due to their ability to kill antigen-presenting cells and their lymphokine-mediated effector activity, Th1 cells are associated ...
CD4 (T-Helper/Inducer Cell Marker) Antibody - With BSA and Azide, Mouse Monoclonal Antibody [Clone C4/206 ] validated in IF, FC ... CD4 is a membrane glycoprotein of T lymphocytes that interacts with major histocompatibility complex class II antigens and is ... CD4 (T-Helper/Inducer Cell Marker) Antibody - With BSA and Azide is for research use only and not for use in diagnostic or ... home , Products , Primary Antibodies , Stem Cells , CD4 (T-Helper/Inducer Cell Marker) Antibody - With BSA and Azide ...
... helper-inducer) T cell subset. Patients with sarcoidosis whose clinical indices suggested activity showed an increased number ... of macrophages coexpressing RFD1 and RFD7 antigens, of macrophages expressing UCHM1 and lymphocytes expressing activation ... an epithelioid cell antigen (RFD9), and a circulating monocyte antigen (UCHMI). The increase in RFD1+ cells appeared to be due ... The lymphocytes in lavage fluid from patients with sarcoidosis were characterised by increased expression of activation markers ...
This pathogen selectively infects lymphocytes bearing a T4 surface antigen. These helper/inducer T-cells are responsible for ... HCMV is known to result in a suppression of cell-mediated immunity through depression of levels of T-helper cells with an ... In various clinical studies, T-cell lymphocytes (T4+) were shown to increase in number, opportunistic infections spontaneously ... lymphocytes were higher in the treated group and fewer opportunistic infections occurred. As before, a reversible bone marrow ...
The proportion of helper/inducer T lymphocytes recognized by the presence of CD4 positive antigen on the cell surface is ... lower synthesis of lymphocyte DNA, reduced number of rosetting T lymphocytes, impaired maturation of lymphocytes seen through ... Vitamin B6 deficiency in healthy elderly individuals significantly reduced the total number of lymphocytes, lymphocyte ... lymphocyte proliferation response to mitogens, complement activity and secondary response to antigens. There is also a reduced ...
Injections of mAb specific for antigens on the surface of helper/inducer cells, and for cells expressing IaE antigens provided ... Treatment with OX8 or OX19 achieved stable reductions of splenic and peripheral blood NK cells and helper/inducer T lymphocytes ... helper/inducer cells (W3/25, OX35, OX38), and Ia+ cells (OX6, 3JP, OX17). ... beta cell destruction in the spontaneously diabetic BB/Wor rat is mediated by the combined action of NK and helper/inducer ...
... and helper T-lymphocytes (helper/inducer Tcells). They are formed when lymphocytes circulate through the thymus gland and ... Antigen E and Amb a 1 are synonymous. Antigen E is the old term that was in the regulations for allergenics back in the 80s. ... Abbreviations: Ig = immunoglobulin; IL = interleukin; TH = helper T lymphocytes.. Methods. A. Criteria for Inclusion/Exclusion ... 5. Solid references discussing the relationship between Antigen E U/mL/Amb a 1 U/mL and micrograms of Antigen E U/mL/Amb a 1/mL ...
... helper/inducer) representing 45% of peripheral blood lymphocytes. It is also present on 80% of thymocytes and at a lower level ... Antibody to CD4 recognizes T-helper cells required for recognition of class II antigens. It reacts with ~60% of peripheral ... It is involved in recognition of antigen presented along with MHC class II by APCs. It serves as receptor for HIV. ... gp55, HLA-2, L3 / T4, Ly-4, T cell antigen T4/LEU3, T4, sCD4. ...
Furthermore, the T4 (helper/inducer):T8 (suppressor/cytotoxic) ratio of circulating T lymphocytes of the macaques in the colony ... dramatically diminished proliferative responses of peripheral blood lymphocytes to lectins and antigens. ... We co-cultivated peripheral blood lymphocytes from two macaques with this syndrome with Raji cells, a lymphoblastoid B cell ... The recipients developed evidence of profound lymphocyte dysfunction and have died with active infections by such opportunistic ...
  • Although the HBV nucleoprotein has been suggested to be a major target antigen for CTL , it is entirely possible that selected regions of the viral envelope and other nonstructural proteins such as the polymerase may serve as target structure for HLA class I- or class II-restricted CTL recognition, as has been shown in other viral systems. (elsevier.com)
  • The purpose of this application is to elucidate the pathway(s) required for processing and delivery of cytoplasmic antigens to MHC class II proteins. (elsevier.com)
  • As these co-factors associate with class II proteins in distinct membrane organelles, elucidating their role in cytoplasmic antigen presentation will help dissect the relative importance of the endoplasmic reticulum vs. endosomes in this novel class II pathway. (elsevier.com)
  • In aim 3, experiments to elucidate the role of peptide transporters and heat shock proteins in cytoplasmic antigen presentation via MHC class II molecules are therefore proposed. (elsevier.com)
  • Lymph nodes undergo a sequential progression of changes beginning with follicular hyperplasia early in the disease and ending with an effacement of the nodal architecture and the depletion of lymphocytes. (brown.edu)
  • Differential expression of lymphocyte function-associated antigen 1 (LPA-1) on epidermotropic and non-epidermotropic T-cell clones. (springer.com)
  • A homology search revealed a peptide from human leukocyte function-associated antigen-1 (hLFA-1) as a candidate autoantigen. (lymenet.org)
  • The ring junction contained lymphocyte function associated antigen-1 and talin, but did not trigger polarization and granule translocation to the interface. (ox.ac.uk)
  • Supplementation with vitamin E in healthy elderly people significantly improved lymphocyte proliferation, IL-2 production, DTH, and response to T-cell-dependent vaccines, and reduced the incidence of infections (20,21). (altheal.org)
  • Proliferation of T and B lymphocytes increased following supplementation with vitamin C (22), and increased levels of vitamin C have been associated with lower rate of infections (23). (altheal.org)
  • Lymphocyte proliferation induced by PHA showed an increasing trend with palmvitee supplementation in both smokers and nonsmokers. (biomedcentral.com)
  • It is the interaction of an Ia-positive antigen-presenting cell (macrophage or B cell) with an antigen-specific T helper cell that is the key initial event in the immune response. (elsevier.com)