#antigen

• Agglutinogen — An antigen substance, protein or carbohydrate in nature, located on the outer surface of the erythrocyte membrane, bacteria, or other biological cells. Its structural interaction with a specific agglutinin in the plasma triggers the agglutination reaction, serving as the core biochemical element that defines blood types within the ABO and Rh systems.
• Allergen — A substance of organic or inorganic nature (antigen) capable of inducing a hypersensitivity reaction or an exaggerated immune response (allergy) in previously sensitized organisms. Among the most common allergens are pollen, dust mites, molds, certain foods (peanuts, milk, shellfish), some medications, or insect venom.
• Allotype — A genetic variation or structural antigenic determinant within a protein or immunoglobulin (antibody) that differentiates individuals within the same species. This form of molecular polymorphism reflects the presence of different alleles at the corresponding gene locus, utilized as an essential biological marker in population genetics, forensics, and immunogenetics.
• Allotypic — Pertaining to or relating to an allotype, or presenting a structural variation specific to a subset of individuals within the same species. In immunogenetics, it describes antigenic determinants or polymorphic sequence modifications of serum proteins; in psychology, it can refer to behaviors or traits externally adapted or determined by complementary factors.
• Antibody — A complex protein molecule (immunoglobulin) synthesized by B lymphocytes of the immune system in response to the entry of a foreign substance (antigen) into the body, possessing the specific structural capacity to bind to it for neutralization or destruction. This biological barrier forms the foundation of acquired immunity, ensuring defense against bacteria, viruses, and toxins.
• Antigen — Any macromolecular substance (protein, polysaccharide, or toxin), usually foreign to the body, capable of triggering a specific immune response, stimulating antibody synthesis, and reacting specifically with them. As an adjective, it describes an element possessing this immunogenic property.
• Antigenic — The feminine form of the adjective 'antigen' or a feminine noun variant used to designate an immune-triggering substance; it describes a molecular, viral, or cellular structure capable of stimulating the immune system to produce specific antibodies.
• Antigenic — Relating to antigens or possessing the property to act as an antigen; characterized by the capacity to stimulate a specific immune response. In modern virology, it describes viral genetic mutations (such as antigenic drift or shift) allowing pathogens to evade host antibodies.
• Antigen therapy — An advanced therapeutic method based on the controlled administration of specific antigens (tumoral, viral, or bacterial) into the body to stimulate, re-educate, or enhance the native immune response against a severe pathology. In modern oncology, antigen therapy includes the use of personalized therapeutic vaccines.
• Autoanaphylaxis — A severe and rare form of anaphylactic-type reaction (acute hypersensitivity) triggered inside the body by its own pathologically modified substances or proteins, acting as autoantigens, without requiring the introduction of an external allergen from the environment.
• Autoantibody — An antibody produced by an individual's immune system that, due to a functional recognition error, is pathologically directed against the host organism's own cells, tissues, or molecular constituents; a central factor in the triggering, progression, and clinical diagnosis of autoimmune diseases.
• Autoantigen — A normal molecular constituent, macromolecule, protein, or cellular structure native to an organism that, under conditions of impaired immune tolerance, is erroneously recognized as a foreign substance (antigen) and becomes the target of an attack triggered by its own immune system.