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Related to tumor antigen: Cancer Antigen


see immunityimmunity,
ability of an organism to resist disease by identifying and destroying foreign substances or organisms. Although all animals have some immune capabilities, little is known about nonmammalian immunity.
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A substance that initiates and mediates the formation of the corresponding immune body, termed antibody. Antigens can also react with formed antibodies. Antigen-antibody reactions serve as host defenses against microorganisms and other foreign bodies, or are used in laboratory tests for detecting the presence of either antigen or antibody. See Antibody, Antigen-antibody reaction

A protein immunogen (any substance capable of inducing an immune response) is usually composed of a large number of antigenic determinants. Thus, immunizing an animal with a protein results in the formation of a number of antibody molecules with different specificities. The antigenicity of a protein is determined by its sequence of amino acids as well as by its conformation. Antigens may be introduced into an animal by ingestion, inhalation, sometimes by contact with skin, or more regularly by injection into the bloodstream, skin, peritoneum, or other body part.

With a few exceptions, such as the autoantigens and the isoantigens of the blood groups, antigens produce antibody only in species other than the ones from which they are derived. All complete proteins are antigenic, as are many bacterial and other polysaccharides, some nucleic acids, and some lipids. Antigenicity may be modified or abolished by chemical treatments, including degradation or enzymatic digestion; it may be notably increased by the incorporation of antigen into oils or other adjuvants. See Isoantigen

Bacteria, viruses, protozoans, and other microorganisms are important sources of antigens. These may be proteins or polysaccharides derived from the outer surfaces of the cell (capsular antigens), from the cell interior (the somatic or O antigens), or from the flagella (the flagellar or H antigens). Other antigens either are excreted by the cell or are released into the medium during cell death and disruption; these include many enzymes and toxins, of which diphtheria, tetanus, and botulinus toxins are important examples. The presence of antibody to one of these constituent antigens in human or animal sera is presumptive evidence of past or present contact with specific microorganisms, and this finds application in clinical diagnosis and epidemiological surveys. See Botulism, Diphtheria, Toxin

Microbial antigens prepared to induce protective antibodies are termed vaccines. They may consist of either attenuated living or killed whole cells, or extracts of these. Since whole microorganisms are complex structures, vaccines may contain 10 or more distinct antigens, of which generally not more than one or two engender a protective antibody. Examples of these are smallpox vaccine, a living attenuated virus; typhoid vaccine, killed bacterial cells; and diphtheria toxoid, detoxified culture fluid. Several independent vaccines may be mixed to give a combined vaccine, and thus reduce the number of injections necessary for immunization, but such mixing can result in a lesser response to each component of the mixture. See Vaccination

Allergens are antigens that induce allergic states in humans or animals. Examples are preparations from poison ivy, cottonseed, or horse dander, or simple chemicals such as formaldehyde or picryl chloride. See Hypersensitivity, Immunology


A substance which reacts with the products of specific humoral or cellular immunity, even those induced by related heterologous immunogens.


a substance that stimulates the production of antibodies
References in periodicals archive ?
The report provides a snapshot of the global therapeutic landscape for Cellular Tumor Antigen P53 (Tumor Suppressor P53 or Antigen NY-CO-13)
Although this construct only contains the variable regions of the mouse monoclonal antibody, a human anti-mouse antibody by the recipient could, after cell infusion, block the interaction between CAR and the target tumor antigen to inhibit the antitumor effect of the CART cells.
Additionally, tests for serum tumor antigens have proven useful as an aid in the assessment of tumor burden, and therapeutic monitoring of breast cancer (Wu and Nakamura, 1997).
The tumor antigen that is targeted in this project is a protein found on the surface of cancer cells.
In initial trials, people with lymphoma, melanoma, or prostate cancer who received dendritic cells primed with a known tumor antigen showed strong anticancer immune responses (SN: 1/13/96, p.
The CAR was designed to recognize a tumor antigen different from the antigen recognized by the synNotch receptor.
Tokyo, Japan) has patented a tumor antigen gene identified by screening a cDNA library derived from a gastric cancer cell line that can induce gastric cancer antigen specific cytotoxic T cell by means of hybridization and PCR utilizing an amino acid sequence of peptide fragment of a known gastric cancer antigen protein, introducing a selected cDNA clone into a cell of gastric cancer cell line that cannot induce gastric cancer antigen specific cytotoxic T cell so that the clone should be expressed in the cell, and selecting a transgenic cell that has acquired the ability to induce cytotoxic T cell.
To eliminate this frustrating inconsistency, the investigators primed the dendritic cells with a unique tumor antigen from the cancer cells of each patient.
This volume covers the main approaches to target discovery and validation, bioinformatics and cancer genes, gene networks, applications in pancreatic cancer and breast tumors, the technology behind discovering differently expressed genes, genome-wide screening using small-interfering RNA expression libraries, hammerhead ribozyme-based target discovery, transgenic animal models, mutation verification, in vivo studies, a model for discovering hematopoiesis and heart failure, the immune system and technical advances in tumor antigen discovery, serological expression cloning, proteomics and identification of tumor antigens, and protein arrays.
The immune-system cells, called T-cells, ignored normal cells carrying HLA-A1 but lacking the tumor antigen.