A toxoid is a bacterial toxin (usually an exotoxin) whose toxicity has been weakened or suppressed either by chemical (formalin) or heat treatment, while other properties, typically immunogenicity, are maintained. In international medical literature the preparation also is known as Anatoxin or Anatoxine.[1] There are toxoids for prevention of diphtheria, tetanus and botulism.[2]
Toxoids are used as vaccines because they induce an immune response to the original toxin or increase the response to another antigen. For example, the tetanus toxoid[3] is derived from the tetanospasmin produced by Clostridium tetani. The latter causes tetanus. Botulin is produced by Clostridium botulinum and it causes the deadly disease botulism.
Multiple doses of tetanus toxoid are used by many plasma centers in the United States for the development of highly immune persons for the production of human anti-tetanus immune globulin (Tetanus Immune Globulin (TIG), HyperTet (c)[4]), which has replaced horse serum type tetanus antitoxin in most of the developed world.