Tick-paralysis toxoid: an effective immunizing agent against the toxin of Ixodes holocyclus.

Glutaraldehyde treatment of the toxin of the Australian paralysis tick Ixodes holocyclus produced a potent, immunogenic toxoid. Three subcutaneous injections (2 to 4 weeks apart) into rabbits produced very high antitoxin titres in their serum, although circulating antitoxin titres declined in the absence of stimulation. Twenty weeks later, immunized rabbits were unaffected by lethal doses of toxin injected subcutaneously.