Antigens


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Antigens

 

colloid substances of high molecular weight which, when introduced into the bodies of animals and man, stimulate the formation of specific antibodies that react with them. An indispensable condition for antigenicity is the difference of the antigen from the substances normally present in the recipient. Antigens consist principally of foreign proteins, some polysaccharides (mostly of bacterial origin), and complexes of proteins and various chemical compounds. There are corpuscular antigens—for example, suspensions of bacteria—which produce agglutination (clumping) reactions with antibodies and soluble antigens—for instance, toxins—which produce precipitation (sedimentation) reactions. Simple proteins of low molecular weight, such as gelatin proteins, are not antigenic. Egg and blood serum albumens (molecular mass 40,000–70,000) have less antigenicity than gamma globulins and other proteins with higher molecular mass (> 160,000). Lipides and carbohydrates that have no antigenic properties and that acquire them in combination with proteins are called haptens. Antigens may be synthesized artificially by combining any of a number of chemical substances with protein. Antigens contain two components, a substance of high molecular weight which is the vehicle for antigenic stimulation (usually a protein) and a nonprotein group whose structure determines the specificity of the given antigen. These groups are called determinants (or specificity factors); they are located on the surface of the antigen and may be separated from the colloid carrier. In certain pathological states—for instance, hemolytic anemia—the body’s own proteins acquire antigenic properties, that is, they become autoantigens. Since proteins have individual specificity, proteins of an animal are antigens for other animals of the same species (isoantigens). It is precisely for this reason that reactions resulting from tissue incompatibility occur in transplants (except in cases of transplant from one monovular twin to another).

References in periodicals archive ?
Sensitivity of antigen: Out of three test antigens (6, 8 and 10 million cells/ml), one with 10 million cells showed visible agglutination with known antisera upto log 10-3 dilution (3000 cells/0.3 ml) as compared to other two antigens (8, 6 million cells/ml) that showed agglutination upto 10-2 dilution (24000cells/0.3ml, 18000cells/0.3ml respectively).
for co-developing cancer immunotherapies based on the MUC1 tumor-associated antigen. We intend to pursue additional collaborations with leading research institutions and others with their novel cancer antigens or technologies suitable for use with our MVA-VLP platform.
The "(https://www.ncbi.nlm.nih.gov/pubmed/20406014) MNS blood group antigens " were discovered in the 1920s by Karl Landsteiner (the same scientist who discovered the ABO system).
TB assay tests for the presence of specific antigens of MTB, i.e., ESAT-6 and CFP-10.
Serological cross-reactivity of the hydatid cyst antigens with taeniid cestodes including Taenia hydatigena and T.
Computer software was utilized to search for exclusive amino acids in the structure of antigens showing positive reactions with an antibody.
pylori antigens in feces and dental plaque in subjects both with infected and non-infected stomachs.
With this enzyme, Jayachandran Kizhakkedathu from the University of British Columbia and colleagues were able to remove the wide majority of the antigens in Type-A and B blood.
Antigens could be any substance, bacteria, viruses, or fungi that stimulate an organism of infection and disease and cause the immune system to produce antibodies.
The Rockefeller University patents licensed by NeoStem are titled: "Methods for use of Apoptotic Cells to Deliver Antigen to Dendritic Cells for Induction or Tolerization of T Cells," (inventors: Matthew Albert, Nina Bhardwaj, Ralph M.
canis QE-13 whole-cell antigens (optical density of 0.8 at 450 nm, Kitasato Laboratories, Saitama, Japan), with serum that had been serially diluted 2-fold with PBS, and incubating the mixture at 50[degrees]C for 24 h.
Identifying which antigens a patient's tumour cells express is the cornerstone of designing cancer therapy for that individual.