Diphtheria toxoid, properties

In the early 1900s, a balanced mixture of diphtheria toxin and antitoxin was found to produce active immunity in both animals and humans. This preparation gained widespread acceptance and protected approximately 85% of recipients. Several years later, diphtheria toxoid was developed by treating the toxin with small amounts of formalin. This process caused the toxin to lose its toxic properties while maintaining its immunogenic properties. In the mid-1920s, the addition of an alum precipitate enhanced the immunogenic properties of the toxoid. 

Toxoids (or antitoxins)—A toxoid is a famed toxin which is treated chemically so that it loses the poisonous or toxic properties but still retains the power to stimulate the body cells to form the appropriate antibody. Typical toxoids are diphtheria toxoid and tetanus toxoid. 

Many antigens currently marketed would be inherently toxic except for the fact they have been stringently detoxified. Some of the most successful and durable vaccines today include toxoided forms of tetanus, pertussis, and diphtheria toxins. During the manufacturing process, these toxoids undergo significant chemical modifications, and their toxic properties are effectively eliminated. The safety is assured with every batch release and defined within safety charac-terization/quality control tests, which are not discussed in this chapter. 

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