Antitoxin, << `an` tee TOK sihn, >> is a substance made by living cells that counteracts illness caused by a toxin. Toxins are poisons produced by living organisms, such as bacteria. Doctors use antitoxins to treat diseases, including tetanus (lockjaw) and diphtheria. Antitoxins are a kind of antibody that can cure or prevent diseases or make them milder (see Immune system ).
Many commercial antitoxins come from animals, such as horses and rabbits. Toxin is injected into an animal’s bloodstream, and the animal produces an antitoxin that circulates in its blood serum. A nonpoisonous, chemically modified toxin called a toxoid is sometimes used to cause the body to produce antitoxin. The blood serum can be removed and then injected into patients. Most animal antitoxins are cheaper and easier to make than human antitoxins. However, animal antitoxins are less effective and may cause bad reactions.
Injected antitoxins usually do not make a patient permanently immune (safe from disease). The antitoxins produced by the body when a person is exposed to a particular toxin are the most effective. In addition, body tissues produce these antitoxins again in future poisonings by the toxin. A reasonable concentration of the antitoxin usually will prevent poisoning. Antitoxins that are produced by another person also are effective in neutralizing a toxin but do not give permanent protection. Permanent immunity can be stimulated in the body by injecting toxoids.
