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poison produced by living organisms. Toxins are classified as either exotoxins or endotoxins. Exotoxins are a diverse group of soluble proteins released into the surrounding tissue by living bacterial cells. Exotoxins have specific reaction sites in the host; e.g.
..... Click the link for more information. treated by heat or chemicals so that its poisonous property is destroyed but its capacity to stimulate the formation of toxin antibodiesantibody,
protein produced by the immune system (see immunity) in response to the presence in the body of antigens: foreign proteins or polysaccharides such as bacteria, bacterial toxins, viruses, or other cells or proteins.
..... Click the link for more information. , or antitoxinsantitoxin,
any of a group of antibodies formed in the body as a response to the introduction of poisonous products, or toxins. By introducing small amounts of a specific toxin into the healthy body, it is possible to stimulate the production of antitoxin so that the body's
..... Click the link for more information. , remains. Because toxoids can be given in large quantities with no risk of tissue damage, they have superseded the highly poisonous toxins as immunizing agents against such diseases as diphtheria and tetanus.
(also anatoxin), a harmless derivative of a toxin that retains its antigenic and immunogenic properties. It is obtained by rendering the toxin harmless with formalin at 37–40°C. A toxoid suitable for immunizing human beings was first obtained in 1923 by the French immunologist G. Ramon. Tetanus and diphtheria toxoids are used as prophylactic measures against these infections. Staphylococcal, botulin, and dysentery toxoids, toxoids produced by the causative agents of gas gangrene and made from the poisons of some poisonous snakes, and other toxoids have been produced and are used for specific prophylaxis and treatment. Toxoids are also used for immunizing horses in order to obtain medicinal antitoxic serums (antitetanus and antidiphtheria).
T. I. BULATOVA