TOXOID

A 'toxoid' is a bacterial toxin whose toxicity has been weakened or suppressed either by chemical (formalin) or heat treatment, while other properties, typically immunogenicity, are maintained. Toxoids are used in vaccines as they induce an immune response to the original toxin or increase the response to another antigen.
For example, the tetanus toxoid is derived from the tetanospasmin produced by ''Clostridium tetani'' and causing tetanus. The tetanus toxoid is used by many plasma centers in the United States for the development of plasma rich vaccines.