Attenuation of Toxins by Interfacial Adsorption. ∗

Abstract

The writer has previously demonstrated that crystalline insulin 1 can be attenuated by interfacial adsorption. In the same communication reference was made to the fact that bacterial toxins can also be attenuated by a similar procedure. It has been found by additional experimentation that ricin, tetanus toxin, staphylococcus toxin and snake venom may be completely detoxified by this method and still retain antigenic properties adequate for purposes of immunization, as demonstrated with rabbits and mice. The following data are representative of the results which have been obtained.

“C.P. ricin” which will produce a pronounced erythema, induration and necrosis when 0.2 cc of a solution of 1 part of ricin in 25,000,000 parts of saline are injected intradermally into rabbits will produce only a faint erythema when equal volumes of the same ricin in dilutions of 1 part of ricin in 1,000 parts of saline are injected after 2 treatments of 48 hours each with chloroform. When triple injections of untreated ricin in dilutions of 1 part ricin in 1,000,000 parts of saline were injected intradermally into rabbits which had been immunized with completely detoxified ricin, only a faint erythema was produced at the site of each injection.

When the serum of each immunized rabbit was mixed with an equal volume of a solution of ricin containing 1 part of ricin in 200,000 parts of saline, and the mixture (0.2 cc) injected intradermally into normal rabbits, no symptoms of any kind were produced.

Tetanus toxin† containing 70,000 (guinea pig) M.L.D.'s per cc was completely detoxified when treated twice for 48 hours by interfacial adsorption. Five cc of the detoxified toxin produced no symptoms of any kind when injected subcutaneously into guinea pigs. Groups of mice (50 each) treated with the detoxified toxin all survived this treatment and smaller groups of these subsequently survived injections of 1 and 2 M.L.D.'s of untreated toxin without symptoms of tetany.