Toxoid

toxoid, protein toxin treated by heat or chemicals so that its poisonous property is destroyed but its capacity to stimulate the formation of toxin antibodies, or antitoxins, 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 Because toxoids can be given in large quantities with no risk of tissue damage, they have superseded the highly poisonous toxins as immunizing agents against such diseases as diphtheria and tetanus.

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toxoid

Bacterial toxin that has been made inactive but can still combine with or stimulate formation of antibodies. In many bacterial diseases, the bacteria produce a toxin that causes the disease manifestations. Heating the toxin or treating it chemically converts it into a harmless toxoid that can be injected into a human or a nonhuman animal to confer immunity from subsequent infection. The vaccines for tetanus and diphtheria are toxoids.

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toxoid [′täk‚sȯid]

(immunology)

Detoxified toxin, but with antigenic properties intact; toxoids of tetanus and diphtheria are used for immunization.

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Toxoid 

(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