antibody
(ant'i-bod‵ē 
)
[ anti- + body ]
ABBR: Ab
A substance produced by B lymphocytes in response to a unique antigen. Each Ab molecule combines with a specific antigen to destroy or control it. All antibodies, except natural antibodies (antibodies to different blood types), are made by B cells stimulated by a foreign antigen, typically a foreign protein, polysaccharide, or nucleic acid. SYN: immunoglobulin.
SEE: illus. ; antigen; autoantibody; cytokine; isoantibody .
Antibodies neutralize or destroy antigens in several ways. They can initiate lysis of the antigen by activating the complement system; neutralize toxins released by bacteria, coating (opsonizing) the antigen or forming a complex to stimulate phagocytosis; promote antigen clumping (agglutination); or prevent the antigen from adhering to host cells.
An antibody molecule consists of four polypeptide chains (two light and two heavy), which are joined by disulfide bonds. The heavy chains form the complement-binding site, and the light and heavy chains form the site that binds the antigen.
acetylcholine-receptor binding a.
ABBR: AChR-Ab
An autoantibody against acetylcholine receptors in the neuromuscular junction. Binding, blocking, or modulating antibodies against this receptor are found in the blood of most patients with generalized myasthenia gravis and in about half of all patients with ocular forms of the disease.agonistic a.An antibody that stimulates or activates an organ. For example, agonistic antibodies against the thyrotropin receptor in Graves disease stimulate the thyroid gland to release thyroid hormones that produce hyperthyroidism.
antiactin a.An antibody detected in patients with autoimmune hepatitis. SYN: antismooth muscle antibody.
antiaminoacyl tRNA synthetase a.
ABBR: ARS
Any of several autoantibodies found in patients with autoimmune interstitial pneumonias and the antisynthetase syndrome.ABBR: aCLa
An autoantibody against the cell membrane lipid, diphosphatidyl glycerol. It produces abnormal and sometimes life-threatening blood clotting. The antibody is found in a variety of autoimmune and infectious diseases, including in patients with the antiphospholipid antibody syndrome and syphilis.anticyclic citrullinated peptide a.
ABBR: anti-CCP
An antibody that is sensitive and specific for rheumatoid arthritis, and a biomarker of the severity of the disease. SYN: anti-cyclized citrullinated peptide antibody; anti-CCP antibody.anticytosolic 5' nucleotidase 1A a.
ABBR: anti-cN1A; anti-NT5C1A
An autoantibody that inhibits a protein that processes RNA. It is a biomarker of inclusion body myositis (aninflammatory myopathy).anti–DNase B a.An antibody formed during infection with group A beta-hemolytic streptococci. It is used, retrospectively, to help diagnose recent streptococcal infections.
antidrug a.An antibody that prevents a drug from exerting its intended effect. Injected drugs are especially susceptible to antidrug antibody neutralization.
antiendomysial a.An antibody that cross-reacts with smooth muscle collagen and the gluten in wheat, found in the serum of people with celiac sprue and some related autoimmune diseases.
antiendothelial cell a.An autoantibody present in the serum of patients with a variety of autoimmune diseases, including scleroderma (systemic sclerosis), systemic lupus erythematosus, interstitial lung diseases, and sarcoidosis. These cells attach to antigens on the cells that line blood vessels and injure those cells, producing blood vessel injury and inflammation (vasculitis).
antifibrillarin a.An autoantibody to the nucleolar protein fibrillarin, found in patients with diffuse systemic sclerosis (scleroderma), esp. those with relatively severe disease. It is identified more often in men than in women with the disease and in people of African descent.
antiganglioside a.An antibody formed against the chemical components of nerves, found in the serum of those with Guillain-Barré syndrome.
antigliadin a.An antibody formed against the gluten in wheat, found in the serum of some people with celiac sprue.
antigranulocyte a.An autoantibody that binds to nuclear antigens in granulocytic white blood cells. Antigranulocyte antibodies decrease the number of circulating white blood cells, i.e., they can cause neutropenia.
antihistone a.Antibodies that are found in the blood of patients with drug-induced lupus and occasionally in systemic lupus erythematosis.
anti-hMG-CoA reductase a.An antibody against 3-hydroxy-3-methylglutaryl-coenzyme A reductase. It is found in people with statin-associated autoimmune myopathy, a rare condition marked by severe weakness of the proximal muscles (e.g. of the hips or shoulders), muscle fiber necrosis, and markedly abnormal serum levels of creatine kinase (CK).
anti-Hu a.An autoantibody associated with paraneoplastic encephalomyelitis. It is also known as ANNA-1 (antineuronal nuclear antibody-1).
antileukocyte a.Any antibody found in plasma that, when donated and infused into a recipient, damages the recipient's white blood cells. Leukocyte injury after plasma exchange or infusion triggers transfusion-related acute lung injury.
antimannan a.A biomarker for infection with Cand ida species. The presence of antibodies when found with mannan antigens can be used as a diagnostic surrogate for a positive culture in people who are thought to have deep-seated infections with Cand ida.
antimelanoma differentiation-associated gene 5 a.
ABBR: Anti-MDA-5
An autoantibody that targets an RNA-specific helicase. It is a biomarker of clinically myopathic dermatomyositis and fulminant interstitial lung disease, esp. in people of Chinese ancestry.anti-Mi-2 a.An autoantibody that targets a nuclear antigen involved in the regulation of gene transcription. It is often present in patients with dermatomyositis.
antimicrosomal a.An autoantibody found in the plasma of patients with thyroid injury, e.g., in several forms of thyroiditis and other rheumatologic or autoimmune diseases.
antimyelin-associated glycoprotein a.
ABBR: anti-MAG antibodies
Immunoglobulin M antibodies that are a potential cause of paraproteinemic polyneuropathy.antimyeloperoxidase a.An antibody found in patients with several autoimmune vasculitides, such as microscopic polyangitis. SYN: perinuclear antineutrophil cytoplasmic antibody .
ABBR: ANNA
Any of several antibodies that bind to neuronal targets in the cerebrum and cerebellum, producing paraneoplastic neurological dysfunction. The antibodies are typically released by cancers such as small-cell carcinoma of the lung (also known as ANNA-1 and ANNA-2), testicular cancer (anti-Ta antibody), or breast cancer (ANNA-2).ABBR: ANCA
Any of a group of autoantibodies found in the blood of patients with certain forms of vasculitis (such as Churg-Strauss syndrome, microscopic polyangiitis, and granulomatosis with polyangiitis), esp. when it affects small blood vessels.ABBR: ANA
Any of a group of autoantibodies that react against normal components of the cell nucleus. They are present in several immunologic diseases, including systemic lupus erythematosus, progressive systemic sclerosis, Sjögren syndrome, scleroderma, polymyositis, and dermatomyositis, and in some patients taking hydralazine, procainamide, or isoniazid. In addition, ANA is present in some normal people. Tests for ANAs are used in the diagnosis and management of autoimmune diseases.antiphospholipase A2 receptor a.An autoantibody found in people with membranous glomerulopathy but not in other autoimmune or renal diseases.
ABBR: aPLa
Any of a group of immunoglobulin autoantibodies that react with phospholipids, which are one of the primary components of the cell membrane (the other components being glycolipids and steroids). These antibodies are found in patients with a variety of connective tissue and infectious disorders, including systemic lupus erythematosus, the antiphospholipid antibody syndrome, syphilis, and malaria. They cause abnormal blood clotting, thrombocytopenia; and in women of childbearing age, repeated miscarriages. The anticardiolipin antibodies are one type of antiphospholipid antibody.antiproliferating cell nuclear antigen (PCNA) a.
ABBR: anti-PCNA
An antibody found in the blood of patients with diseases in which cells replicate rapidly. Such conditions include autoimmune and inflammatory diseases and malignancies.antiproteinase-3 a.An autoantibody found in patients with small blood vessel vasculitides, such as granulomatosis with polyangiitis. SYN: diffusely cytoplasmic antineutrophil antibody .
antireceptor a.An antibody that reacts with the antigen receptor on a cell rather than with an antigen itself.
antiribosomal P a.An autoantibody found in patients with systemic lupus erythematosus, esp. those with neurological or psychiatric manifestations of the disorder.
anti-S a.Antibodies formed against the spike (“S”) protein of SARS-CoV-2, the virus that causes Covid-19.
anti–scl-70 a.Antitopoisomerase I antibody.
antisignal recognition particle a.
ABBR: anti-SRP
An autoantibody that targets polypeptides that ferry proteins to the endoplasmic reticulum of the cell for processing. It is a biomarker of severe (necrotizing) autoimmune myopathy.antismooth muscle a.Antiactin antibody.
ABBR: TPOAb
A serum marker of autoimmune thyroid destruction, i.e., of Graves disease or Hashimoto thyroiditis.antititin a.An antibody that reacts with striated muscle cells. It is found principally in people with myasthenia gravis who also have thymoma.
antitopoisomerase I a.An autoantibody found in the serum of patients with progressive systemic sclerosis, silicosis, and systemic lupus erythematosus. Higher levels of the antibody correlate with worsening kidney, lung, and skin disease. SYN: anti-scl-70 antibody .
blocking a.An antibody that prevents an antigen from binding with a cellular receptor.
ABBR: bNAbs
Antibodies that can block many strains or subtypes of human immunodeficiency virus (HIV) from entering and infecting cells.cross-reacting a.An antibody that reacts with antigens other than its specific antigen because they contain binding sites that are structurally similar to its specific antigen.
SEE: antigenic determinant.
cytotoxic a.An antibody that lyses cells by binding to a cellular antigen and activating complement or killer cells.
diffusely cytoplasmic anti-neutrophil cytoplasmic a.
ABBR: C-ANCA.
Antiproteinase-3 antibody.direct fluorescein-conjugated a.
ABBR: DFA
Direct fluorescent antibody.ABBR: DFA
A fluorescent antibody test performed on sputum to detect microorganisms that invade the respiratory tract, e.g., Legionella, Mycoplasma, or Bacillus anthracis. SYN: direct fluorescein-conjugated antibody ; direct immunofluorescence test.SEE: Donath-Land steiner antibody.
ABBR: FA
An antibody that has been stained or marked by a fluorescent material. The fluorescent antibody technique permits rapid diagnosis of various infections.glutamic acid decarboxylase a.
ABBR: GADA
One of the antibodies associated with type 1 diabetes. It is also found in patients with stiff-person syndrome.immune a.An antibody produced by immunization or as a result of transfusion of incompatible blood.
maternal a.An antibody produced by the mother and transferred to the fetus in utero or during breastfeeding.
ABBR: MoAB
A type of antibody, specific to a certain antigen, created in the laboratory from hybridoma cells. Because monoclonal antibodies are derived from a single cell line and raised against a single antigen, they are highly specific. Diagnostically, they are used to identify microorganisms, white blood cells, hormones, and tumor antigens. In patient care they are used to treat autoimmune diseases, some cancers, transplant rejection, and some infections (such as coronavirus and respiratory syncytial virus).Hybridoma cells, used to produce monoclonal antibodies, are formed by the fusion of a spleen cell from a mouse immunized with an antigen and a multiple myeloma cell (a cancerous plasma B cell). The fused cells are screened to identify those that secrete antibodies against a specific antigen. A continuous supply of these antigen-specific monoclonal antibody secreting cells can then be grown in cultures.
SEE: antibody; B cell; hybridoma.
natural a.An antibody present in a person without known exposure to the specific antigen, such as an anti-A antibody in a person with blood type B. Most natural antibodies are immunoglobulins of the M class (IgM).
neutralizing a.An antibody that binds to a disease-causing organism and prevents it from causing disease.
The goal of vaccination is to produce neutralizing antibodies against pathogens, such as SARS-CoV-2 (the virus that causes Covid-19).
ABBR: PRA
A measure of an organ transplant recipient's level of sensitization to antigens on donated organs. It is the percentage of cells taken from a broad selection of blood donors against whose antigens the organ recipient's serum reacts. The higher the panel reactive antibody, the more challenging it is to match a donor organ to the recipient.perinuclear antineutrophil cytoplasmic a.Antimyeloperoxidase antibody.
p504s a.Alpha-methylacyl-CoA racemase.
polyclonal a.An antibody that reacts with many different antigens.
polygonal antibody A group of antibodies used together to identify a variety of chemical structures present on an antigenic substance.
protective a.An antibody produced in response to an infectious disease.
SEE: immunity.
radionuclide-linked monoclonal a.A monoclonal antibody to which a radioisotope has been attached. The antibody attaches to receptors on the surface of undesired cells, e.g., cancer cells, and delivers a dose of radiation directly to those cells, leaving healthy cells and tissues relatively unaffected.
toxin-linked monoclonal a.A monoclonal antibody to which a cell-killing drug has been attached. The antibody combines preferentially with receptors on undesired cells (such as cancer cells) and delivers its lethal drug to those cells but not to healthy cells and tissues. To increase their effectiveness and decrease immune responses to these cells, genes for antigen binding sites from human antibodies are added, creating humanized monoclonal antibodies.
TSH-receptor a.Long-acting thyroid stimulator.
unexpected a.Any antibody other than ABO-type antibodies identified in either donor or recipient plasma. Such antibodies are a cause of hemolytic transfusion reactions.