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Related to Cancer Antigen: Cancer antigen 19-9, Cancer antigen 15-3


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

McGraw-Hill Concise Encyclopedia of Bioscience. © 2002 by The McGraw-Hill Companies, Inc.


A substance which reacts with the products of specific humoral or cellular immunity, even those induced by related heterologous immunogens.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.


a substance that stimulates the production of antibodies
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
References in periodicals archive ?
Abbreviations: AUC, area under the curve; DRE, digital rectal examination; PCa, prostate cancer; PCA3, prostate cancer antigen 3.
Family 4, like family 2, is directed to cancer antigens, specifically other immunogenic portions of MUC1.
[8] Nonstandard abbreviations: CEA, carcinoembryonic antigen; PSA, prostate-specific antigen; CA125, cancer antigen 125; CA19-9, cancer antigen 19-9; BCG, bacille Calmette-Guerin; ADCC, antibody-dependent cell-mediated cytotoxicity; OC125, ovarian cancer 125; CA125II, heterologous double-determinant CA125 assay; FDA, US Food and Drug Administration; ROMA, risk of ovarian malignancy algorithm; HE4, human epididymis protein 4; PPV, positive predictive value; PLCO, Prostate, Lung, Colon, and Ovary Cancer (Screening Trial); TVS, transvaginal sonography; UKCTOCS, UK Collaborative Trial of Ovarian Cancer Screening; ROCA, Risk of Ovarian Cancer Algorithm; SPORE, Specialized Program of Research Excellence; CEACAM, CEA cell adhesion molecule; USPSTF, US Preventive Services Task Force.
We are excited to enter this alliance with Agensys to generate fully human antibody candidates to their large portfolio of novel, clinically relevant cancer antigens," stated R.
Prostate cancer detection in the "grey area" of prostate-specific antigen below 10 ng/ml: head-to-head comparison of the updated PCPT calculator and Chun's nomogram, two risk estimators incorporating prostate cancer antigen 3.
The liposome enhances recognition of the cancer antigen by the immune system and facilitates better delivery.
MIAMI -- A test for circulating lysophosphatidic acid dramatically improves detection of early-stage ovarian cancer, compared with current screening methods dependent on cancer antigen 125, Yan Xu, Ph.D., said at the annual science writers seminar sponsored by the American Cancer Society.
Its lead programme is an affinity enhanced T-cell therapy targeting the NY-ESO cancer antigen. Its NY-ESO TCR affinity enhanced T-cell therapy has demonstrated signs of efficacy and tolerability in Phase I/II trials in solid tumors and in hematologic cancer types.
A promising new prostate cancer marker, PCA3 (prostate cancer antigen 3), has recently become available, and its utility for predicting short-term biopsy progression has been studied in an active surveillance program (2).
The Risk of Ovarian Malignancy Algorithm (ROMA) stratifies women as being at high or low risk for epithelial ovarian cancer based on menopausal status and preoperative serum levels of two biomarkers: human epididymis protein 4 (HE4) and cancer antigen 125 (CA 125).
[4] Nonstandard abbreviations: PSA, prostate-specific antigen; EPCA-2, early prostate cancer antigen 2; S/N, signal-to-noise; EDRN, Early Detection Research Network.
In Jordan, Biolab currently offers prostate cancer antigen gene (PCA3) testing, AmnioPCR, Y chromosome microdeletions tests, and Anti Mullerian hormone testing, a new market for ovarian reserve along with several other tests.