Antibody
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antibody
[an´tĭ-bod″e]an immunoglobulin molecule having a specific amino acid sequence that gives each antibody the ability to adhere to and interact only with the antigen that induced its synthesis. This antigen-specific property of the antibody is the basis of the antigen-antibody reaction that is essential to an immune response. The antigen-antibody reaction begins as soon as substances interpreted as foreign invaders gain entrance into the body. See also immunity. Abbreviated Ab.
Antibodies are synthesized by the plasma cells formed when antigen-specific groups (clones) of B lymphocytes respond to the presence of antigen. The developmental process of antibody production begins when stem cells are transformed into B lymphocytes; this transformation usually is completed a few months after birth, at which time the lymphocytes migrate to lymphoid tissue primarily located in the lymph nodes, although they are also found in the spleen, gastrointestinal tract, and bone marrow.
Antibody production, its interaction with a specific antigen, and the activation of complement (C), an interrelated group of eleven proteins, are the major components of the humoral system of immunity.
Fortunately, the immune response of antibody and complement can be transferred passively from one individual to another, as for example the transfer of maternal antibody across the placental barrier to the fetus, who has not yet developed a mature immune system. An antibody present in an individual without known prior exposure to the corresponding red cell antigen is termed an isoagglutinin. (Examples are the ABO antibodies anti-A, anti-B, and anti-A,B.)
Antibodies can be classified according to their mode of action as they react to and set about defending the body against foreign invaders. Some cause clumping together of bacterial cells (agglutination) and are called agglutinins. Those antibodies that cause bacterial cells to dissolve or liquefy are called bacteriolysins. This activity is assisted by complement, which interacts with the antigen-antibody complex in such a way that the cell ruptures and there is dissolution (lysis) of the cell body. Opsonins coat the outside of bacteria, making them more attractive to phagocytes. Other types of antibodies include those that neutralize the toxins of antigens (antitoxins) and those that cause precipitation of antigens in a fluid medium (precipitins).
Antibodies are synthesized by the plasma cells formed when antigen-specific groups (clones) of B lymphocytes respond to the presence of antigen. The developmental process of antibody production begins when stem cells are transformed into B lymphocytes; this transformation usually is completed a few months after birth, at which time the lymphocytes migrate to lymphoid tissue primarily located in the lymph nodes, although they are also found in the spleen, gastrointestinal tract, and bone marrow.
Antibody production, its interaction with a specific antigen, and the activation of complement (C), an interrelated group of eleven proteins, are the major components of the humoral system of immunity.
Antibody-mediated immunity. From Applegate, 2000.
Antibodies can be classified according to their mode of action as they react to and set about defending the body against foreign invaders. Some cause clumping together of bacterial cells (agglutination) and are called agglutinins. Those antibodies that cause bacterial cells to dissolve or liquefy are called bacteriolysins. This activity is assisted by complement, which interacts with the antigen-antibody complex in such a way that the cell ruptures and there is dissolution (lysis) of the cell body. Opsonins coat the outside of bacteria, making them more attractive to phagocytes. Other types of antibodies include those that neutralize the toxins of antigens (antitoxins) and those that cause precipitation of antigens in a fluid medium (precipitins).
anaphylactic antibody a substance formed as a result of the first injection of a foreign anaphylactogen and responsible for the anaphylactic symptoms following the second injection of the same anaphylactogen.
antinuclear a's (ANA) autoantibodies directed against components of the cell nucleus, e.g., DNA, RNA, and histones; they may be detected by immunofluorescence. A positive ANA test is characteristic of systemic lupus erythematosus. Antinuclear antibodies also occur in patients with rheumatoid arthritis, Sjögren's syndrome, and scleroderma.
blocking antibody any antibody that by combining with an antigen blocks another immunologic reaction with the antigen. Immunotherapy (hypersensitization) for allergic disorders induces in most treated patients IgG blocking antibodies that can bind the allergen and prevent it from binding to cell-fixed IgE and trigger immediate hypersensitivity; thus it can induce partial immunologic tolerance. Blocking antibodies can prevent agglutination in serologic tests.
complement-fixing antibody antibody (primarily IgM and the IgG subclasses 1, 2, and 3) that activates complement when reacted with antigen.
complete antibody antibody capable of agglutinating cells in physiologic saline solution.
cross-reacting antibody one that combines with an antigen other than the one that induced its production.
cytophilic antibody cytotropic antibody.
cytotoxic antibody any specific antibody directed against cellular antigens, which when bound to the antigen, activates the complement pathway or activates killer cells, resulting in cell lysis.
cytotropic antibody any of a class of antibodies that attach to tissue cells (such as mast cells and basophils) through their Fc segments to induce the release of histamine and other vasoconstrictive amines important in immediate hypersensitivity reactions. In humans this antibody, also known as reagin, is of the immunoglobulin class known as IgE. Called also cytophilic antibody.
heterophil antibody a characteristic antibody found with many cases of infectious mononucleosis; see also heterophil antibody.
immune antibody a type of isoantibody induced by immunization, either by pregnancy or by transfusion, in contrast to natural antibodies.
incomplete antibody
1. antibody that binds to erythrocytes or bacteria but does not produce agglutination; in blood banking, the nonagglutinating antibody is detectable in serum by using the antiglobulin (Coombs') test. For example, IgG anti-Rh antibodies do not agglutinate erythrocytes in physiologic saline whereas IgM antibodies do.
2. a univalent antibody fragment.
monoclonal a's (MOAB) proteins produced from a single clone of B lymphocytes; used as laboratory reagents in radioimmunoassays, ELISA assay, and immunofluorescence assays, and also as biological response modifiers fused with rapidly reproducing myeloma cells, resulting in a hybridoma capable of synthesizing a massive amount of one specific antibody; the antibody is made in response to tumor cells injected into mice and is produced from mouse serum. Monoclonal antibodies may be used alone (unconjugated) or bound (conjugated) to radioisotopes, toxins, or other biological response modifiers. When bound to radioisotopes they may also be used as a diagnostic tool to locate tumors and metastatic disease.
natural a's (naturally occurring a's) antibodies present in the serum of normal individuals in the apparent absence of any contact with the specific antigen, probably induced by exposure to cross-reacting antigens; examples are the ABO antibodies, anti-A and anti-B. Such antibodies may play a major role in resistance to infection.
neutralizing antibody one that reduces or destroys infectivity of a homologous infectious agent by partial or complete destruction of the agent.
protective antibody one responsible for immunity to an infectious agent, observed in passive immunity.
Rh a's those directed against Rh antigen(s) of human erythrocytes. Not normally present, they may be produced when Rh-negative persons receive Rh-positive blood by transfusion or when an Rh-negative person is pregnant with an Rh-positive fetus.
saline antibody complete antibody.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
an·ti·bod·y (Ab),
(an'tē-bod'ē), Avoid the jargonistic use of the plural antibodies when the reference is to a single antibody species.An immunoglobulin molecule produced by B-lymphoid cells that combine specifically with an immunogen or antigen. Antibodies may be present naturally, their specificity is determined through gene rearrangement or somatic replacement or may be synthesized in response to stimulus provided by the introduction of an antigen; antibodies are found in the blood and body fluids, although the basic structure of the molecule consists of two light and two heavy chains, antibodies may also be found as dimers, trimers, or pentamers. After binding antigen, some antibodies may fix, complement, bind to surface receptors on immune cells, and in some cases may neutralize microorganisms.
See also: immunoglobulin.
See also: immunoglobulin.
Farlex Partner Medical Dictionary © Farlex 2012
antibody
(ăn′tĭ-bŏd′ē)n. pl. antibod·ies
A Y-shaped protein on the surface of B cells that is secreted into the blood or lymph in response to an antigenic stimulus, such as a bacterium, virus, parasite, or transplanted organ, and that neutralizes the antigen by binding specifically to it; an immunoglobulin.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
antibody
An immunoglobulin produced by plasma cells, which has a specific amino acid sequence and specifically binds to the antigen(s) (e.g., foreign proteins, microbes or toxins) that induced its synthesis; antibodies may also bind to closely related antigens.Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.
antibody
Immunology An immunoglobulin produced by plasma cells, which has a specific amino acid sequence and specifically binds to the antigen(s)–eg, foreign proteins, microbes or toxins, that induced its synthesis; antibodies may bind to closely related antigens. See Acetylcholine receptor antibody, Anticardiolipin antibody, Anticentromere antibody, Anti-double-stranded DNA antibody, Anti-epidermal antibody, Anti-extractable nuclear antibody, Antigliadin antibody, Antihistone antibody, Anti-idiotype antibody, Anti-insulin antibody, Anti-islet cell antibody, Anti-Jo-1 antibody, Anti-LANA antibody, Antimicrosomal antibody, Antimitochondrial antibody, Antimyelin antibody, Antimyeloperoxidase antibody, Antineuronal-nuclear antibody, Antineutrophil cytoplasmic antibody, Antinuclear antibody, Antiparietal cell antibody, Anti-platelet antibody, Anti-PRP antibody, Anti-Purkinje cell antibody, Anti-receptor antibody, Anti-reticulin antibody, Anti-ribosomal antibody, Anti-Ro/SSA antibody, Anti-single-stranded DNA antibody, Anti-striated muscle antibody, Anti-thyroglobulin antibody, Antithyroid antibody, Antithyroid peroxidase antibody, Anti-tumor necrosis factor- α monoclonal antibody, Autoantibody, Bexxar radiolabeled monoclonal antibody, Secondary antibody, Binding antibody, Blocking antibody, Catabolic antibody, Catalytic antibody, Chimeric antibody, Core antibody, Cross-reactive antibody, Designer antibody, Enhancing antibody, Fluorescent treponemal antibody, Functional antibody, GAD antibody, Glutamic acid decarboxylase autoantibody, HAMA antibody, Heterophile antibody, HIV antibody, HTLA antibody, Humanized antibody, Immunoglobulin, Insulin receptor antibody, Intrinsic factor antibody, Islet antibody, Isotypic control antibody, Ku antibody, LW antibody, Miniantibody, MOC-31 antibody, Monoclonal antibody, Neutralizing antibody, Parietal cell antibody, Plantibody antibody, PM-1 antibody, Polyclonal antibody, Primary antibody, Purkinje cell antibody, RANA antibody, Scleroderma antibody, Sjögren antibody, Sm antibody, Smooth muscle antibody, Sperm antibody, Thyroid stimulating hormone receptor antibody, Trichinosis antibody, Warm antibody.McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.
an·ti·bod·y
(Ab) (an'ti-bod-ē)An immunoglobulin molecule with a specific amino acid sequence evoked in humans or other animals by an antigen and characterized by reacting specifically with the antigen in some demonstrable way, produced by B lymphocytes in response to an antigen. It is believed that antibodies also may exist naturally, without being present as a result of the stimulus provided by the introduction of an antigen.
See also: immunoglobulin
See also: immunoglobulin
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
antibody
A Y-shaped protein molecule, called an IMMUNOGLOBULIN, produced by the B group of lymphocytes in response to the presence of a ANTIGEN. An appropriate B lymphocyte is selected from the existing repertoire. This then produces a clone of PLASMA CELLS each capable of synthesizing large numbers of specific antibodies to combat the infection. The B cells also produce memory cells. Subsequent infection with the same antigen prompts the memory cells to clone plasma cells and produce the correct antibodies without further delay. This is an important way in which an infection leads to subsequent immunity. Antibodies are able to neutralize antigens or render them susceptible to destruction by PHAGOCYTES in the body. The basic structure of an antibody consists of four polypeptide chains linked by disulphide bridges, two larger structures called HEAVY CHAINS and two smaller called LIGHT CHAINS.Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005
antibody (Ab)
a type of protein called an IMMUNOGLOBULIN that reacts with a specific ANTIGEN, and serves as part of a vital body-defence mechanism. Various reactions can occur between antigen and antibody. If the antigen is a TOXIN (as in snake venom, or as produced by bacteria causing, for example, botulism and tetanus), neutralizing antibodies are called antitoxins. If the antigen is adhering to the surface of a cell, antibodies called agglutinins cause clumping or AGGLUTINATION of cells, while another antibody type (lysins) cause disintegration or LYSIS of the cell in conjunction with COMPLEMENT. Other antibodies (opsonins) facilitate uptake of antigens by PHAGOCYTES in the blood, while precipitins cause soluble antigens to precipitate.Antibodies are produced in the lymphoid tissues of the body, e.g. LYMPH NODES, by a type of LYMPHOCYTE called B-CELLS. Most antibodies are produced during exposure to an antigen, such a response being termed active immunity. Specific antibodies to rare or synthetic antigens can be manufactured as easily as those to common antigens. A few antibodies are produced even without the apparent presence of the appropriate antigen. Such ‘natural’ antibodies include several involved in blood grouping, e.g. A and B antibodies in the ABO BLOOD GROUP. Young mammals have limited capacity to produce antibodies in the first few weeks of life, but can obtain some passive immunity by receiving maternal antibodies via the mother's milk. This fact has been used to encourage human mothers to breast-feed their infants rather than bottle-feed. Most antibodies circulate in the blood and other body fluids, but most if not all body secretions also contain antibodies, mainly of the IgA type; See IMMUNOGLOBULIN.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005
Antibody
A protein manufactured by a type of white blood cells called lymphocytes, in response to the presence of an antigen, or foreign protein, in the body. Because bacteria, viruses, and other organisms commonly contain many antigens, antibodies are formed against these foreign proteins to neutralize or destroy the invaders.
Mentioned in: AIDS, AIDS Tests, Alemtuzumab, Allergic Rhinitis, Allergies, Allergy Tests, Amebiasis, Anaphylaxis, Anthrax, Antimyocardial Antibody Test, Antinuclear Antibody Test, Aspergillosis, Ataxia-Telangiectasia, Blood Typing and Crossmatching, Brucellosis, Cholera, Coccidioidomycosis, Cold Agglutinins Test, Coombs' Tests, Cryptococcosis, Cytomegalovirus Antibody Screening Test, Delayed Hypersensitivity Skin Test, Detoxification, Discoid Lupus Erythematosus, Erythroblastosis Fetalis, Fifth Disease, Filariasis, Giardiasis, Goodpasture's Syndrome, Hemolytic Anemia, Hemorrhagic Fevers, Hepatitis A, Hepatitis B, Hepatitis C, Hepatitis D, Hepatitis E, Hepatitis G, Immune Complex Test, Immunoelectrophoresis, Immunoglobulin Deficiency Syndromes, Immunosuppressant Drugs, Infectious Mononucleosis, Japanese Encephalitis, Legionnaires' Disease, Maternal to Fetal Infections, Multiple Myeloma, Myasthenia Gravis, Noroviruses, Plasmapheresis, Polyglandular Deficiency Syndromes, Prostate-Specific Antigen Test, Rabies, Radiation Therapy, Respiratory Syncytial Virus Infection, Rubella Test, Serum Sickness, Shingles, Streptococcal Antibody Tests, Stress Reduction, Threadworm Infection, Tissue Typing, TORCH Test, Transfusion, Tuberculin Skin Test, Typhus, Vaginal Pain, Vasculitis, Waldenström's Macroglobulinemia, X-Linked Agammaglobulinemia
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.
antibody
Any of a large variety of proteins normally present in the body or produced in response to an antigen, which it is capable of combining with and destroying, thus producing an immune reaction. Antibodies are produced by a type of white blood cell called B cell (B lymphocyte) secreted by lymphatic tissue (e.g. bone marrow, lymph nodes) usually in response to an antigen. Some eye diseases are antibody-dependent (e.g. allergic conjunctivitis, atopic keratoconjunctivitis, vernal conjunctivitis).
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann
an·ti·bod·y
(Ab) (an'ti-bod-ē) Avoid the jargonistic use of the plural antibodies when the reference is to a single antibody species.An immunoglobulin molecule produced by B-lymphoid cells that combine specifically with an immunogen or antigen. Antibodies may be present naturally; their specificity is determined through gene rearrangement or somatic replacement or may be synthesized in response to stimulus provided by the introduction of an antigen.
Medical Dictionary for the Dental Professions © Farlex 2012
Patient discussion about Antibody
Q. what is anh cardiolipin antibody
A. Cardiolipin is a protein that is very common in the body. Mostly on heart and skeletal muscles. During several illnesses, mostly autoimmune, our body creates an antibody against it that do great damage and needs to cbe controlled.
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