On the formation of diphtheria toxin in saliva byC. diphtheriae

Summary

• 1. The iron contents of a number of saliva samples were determined. The iron contents found varied from 0.10–0.61 γ per g of saliva, while in some cases the iron quantity present was so small that it could not be determined.

• 2. These iron contents are of the same quantitative order as the concentrations of this element in the various media in use for the preparation of diphtheria toxin.

• 3. Rosebeek claims to have shown the presence in various saliva samples of a number of free amino-acids which also occur in the diphtheria media used at present.

• 4. In view of these facts we thought it likely, that saliva generally would be a suitable medium forC. diphtheriae, in which it ought to be possible to show the formation of diphtheria toxin.

• 5. We have succeeded in demonstrating that in saliva samples which have been inoculated withC. diphtheriae and incubated, a toxin is formed. Upon intracutaneous injection into a guinea pig this toxin produces a characteristic local skin reaction.

• 6. This toxin is thermo-labile, is not neutralized by “normal” serum, but is neutralized specifically by anti-toxic diphtheria serum. So this toxin is diphtheria toxin.

• 7. Therefore saliva is a suitable medium forC. diphtheriae, which can, under certain conditions, form a comparatively strong diphtheria toxin.