Inhibitory Effect of Tetranitromethane on the Diphtheria Toxin–Antitoxin Precipitin Reaction

Abstract

WE have investigated¹ the influence of tetranitromethane on the precipitin reaction between diphtheria toxin and the corresponding horse antiserum. When present in the antibody solution before mixing the serological components, tetranitromethane has a remarkable inhibitory effect on the flocculation, even at very low concentrations. The graph shows the influence of different concentrations of tetranitromethane on the flocculation time (concentrations in mol./litre). When tetranitromethane is added to the antigen before mixing it with the antibody, the effect is very weak, and when it is added to the mixture of the serological components, the flocculation is normal. Tetranitro-methane could easily be removed (by extraction with benzene and other methods) from its mixture with the toxin, but not from its mixture with the serum. Several facts indicate that tetranitromethane inhibits the specific combination of antigen with antibody, not the flocculation of the addition compound.