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a toxin treated by heat or chemical agent to destroy its deleterious properties without destroying its ability to combine with or stimulate the formation of antitoxin.
diphtheria toxoid a sterile preparation of formaldehyde-treated products of the growth of Corynebacterium diphtheriae, used as an active immunizing agent, generally in mixtures with tetanus toxoid and pertussis vaccine (DTP) or with tetanus toxoid alone (DT for pediatric use and Td, which contains less diphtheria toxoid, for adult use).
tetanus toxoid a sterile preparation of formaldehyde-treated products of the growth of Clostridium tetani, used as an active immunizing agent, either in mixtures with diphtheria toxoid and pertussis vaccine (DTP, DT, Td) or by itself (T).
Diphtheria toxin altered so that it cannot cause disease but is still able to stimulate the production of antibodies for active immunization. It is used in diphtheria-pertussis-tetanus vaccine (DTaP).
See also: toxoid