On the Nature of the Toxin-Antitoxin Neutralization Studied on Collodion Particles.

Diphtheria and tetanus toxins can be adsorbed upon collodion particles and can then be neutralized by the adsorption of their antitoxins., When, however, the particles were treated first with tetanus antitoxin and then with tetanus toxin a phenomenon, at first sight paradoxical, appeared, which may be interpreted as the combination of toxin with antitoxin without neutralization. Further observations are presented here. Collodion particles prepared according to Loeb and unconcentrated antitoxic horse serums were used in 3 types of experiment: A—first treatment with the antitoxin, second treatment with the toxin; B—first treatment with normal serum or a non-corresponding antitoxin, second treatment with the toxin; C—treatment with the toxin alone. Tetanus toxin. With antitoxin dilution 1:1 and toxin 1:1 or 1:10, and with antitoxin 1:10 and toxin 1:1 or 1:10, the mice in experiment B showed no symptoms at all; in experiments A and C they either died or had severe symptoms of tetanus. When antitoxin was used in dilution 1:10 and toxin 1:100, the mice in experiments A and B had no symptoms and in experiment C they showed symptoms of tetanus. Diphtheria toxin. Collodion particles treated with diphtheria toxin alone produce a nodule in the skin of guinea pigs, and the skin over the nodule becomes red and scaley 2 or 3 days after the injection. Toxin + antitoxin produces a nodule over which the skin shows no signs of inflammation. With toxin + normal serum the reaction is the same as with toxin alone. If, however, the order of treatment is reversed, that is, if the particles are first treated with anitoxin and then with toxin, the skin in experiment A shows severe inflammation, and in experiment B no inflammation.