On a new method of preparing staphylococcus toxin and toxoid

Summary

• 1. When staphylococcus toxin is prepared according to the method described byParish andClark, the toxin is formed practically exclusively during the first phase of the process. The toxin is formed in and on the soft broth-agar.

• 2. The broth, or the Casamino-acids solution, added at the second stage only serves as an extractive, and does not increase the quantity of toxin.

• 3. This broth or Casamino-acids solution may just as well be replaced by normal physiological saline. This helps to lower the cost of production to some extent, whereas the staphylococcus toxin, or toxoid, thus obtained shows a lower nitrogen content, or, in other words, has a greater degree of “purity” than those obtained by extraction with broth or casamino-acids.

  In case this “saline toxoid” is used in its crude state, it may be expected to cause fewer unpleasant reactions.

• 4. The gas mixture used during the incubation of the “soft agar”, into which the staphylococci are inoculated should contain 30%–60% CO₂. The agar concentration should be lowered from 0.8% (Parish andClark) to 0.5%. The optimal period of incubation is 48 hours. The extraction with physiological saline is most successful at abt. 4°C. for 48 hours. No CO₂ is needed for this.

• 5. By means of 0.25% formol the staphylococcus toxin thus obtained is completely converted into non-toxic staphylococcus toxoid in 8 days at 37°C. Antigen loss during this process is very inconsiderable.

• 6. The toxoids prepared in this way are stable when kept at room temperature. After six months they have practically the same Antitoxin-Binding Power as immediately after preparation and detoxification of the toxin.

• 7. The immunizing effect of “saline toxoid” equals that of antigen solutions obtained by means of “broth” or “Casamino-acids” solution.