750 TOXINS, TOXOIDS, AND ANTITOXINS 



hydrogen-ion concentration in the toxin-antitoxin mixtures prepared in the Bureau of 

 Laboratories, New York City Department of Health, is pH 7.0-7.3. Many preparations of 

 toxin-antitoxin mixtures containing 5 L+, 3 L+, i L-H, and o.i L+ values made from 

 different preparations of toxin were frozen at temperatures of —8° and —26° C. for from 

 eighteen hours to eleven days; all were non-toxic after thawing. The active immunizing 

 value of the frozen products was practically nil. 



PREPARATION AND USE OF TOXOID (aNATOXIN) 



Active immunization with a diphtheria toxin which had been modified with for- 

 mahn was used by Glenny as early as 1904. Glenny and Sudmerson' reported their 

 immunizing experiments with formahzed toxin (toxoid) which was non-toxic for 

 guinea pigs in 5-mil amounts. Since then Glenny and his co-workers' have reported 

 in a series of publications their work on the antigenic value of toxoids, on the detoxi- 

 fication with various amounts of formalin, and also on a rapid and economical method 

 of determining the detoxification rate. They^ call this the "M.R.D. unit," and define 

 it as the smallest quantity of toxin which will produce a reaction when injected into 

 the skin of a guinea pig. 



Ramon,4 in a series of publications, has reported his work on the preparation of 

 toxoids which he terms "anatoxins" and their antigenic value. Ramon's method of 

 detoxifying is as follows: Diphtheria toxin of high potency is freed from organisms 

 by filtration, and formalin is added up to 0.3 per cent concentration. The formalized 

 toxin is then held at 37° C. until 6 mils injected into a 300-gm. guinea pig gives rise 

 to no early or late local or general reactions. Detoxification to this degree requires 

 about three weeks. If samples are removed from time to time and titrated by Ramon's 

 flocculation method, during the course of modification there is no appreciable change 

 in the flocculation value. 



Ramon's results show that these detoxified toxins are valuable immunizing agents. 

 Moloney and Weld and Zingher confirmed these results in animals and humans. 

 Moloney and Weld,^ in their studies on the preparations of formalinized toxins, show 

 that when toxins containing 0.5 per cent phenol are used, the antigenic value after 

 detoxifying is practically nil. This explains the failure by the writer to obtain a good 

 antigenic toxoid in the early work as all the work was done on phenolized toxin. 

 Moloney and Weld also point out that between pH 7 and pH 10 the rate of detoxifica- 

 tion is greater the more alkaline the solution. At pH 10 they find that detoxifica- 

 tion is associated with a loss of flocculation value and therefore recommend pH 9.0 

 as the optimum hydrogen-ion concentration for the rapid production of toxoids. 

 They are able completely to detoxify the formalinized toxin pH 8.2 in five days by 

 incubating at 37° C. They state the product loses none of its immunizing value when 

 left at room temperature for many months. 



' Glenny, A. T., and Sudmerson, H. J.: J. Hyg., 20, 184. 1921. 



» Glenny, A. T., and Hopkins, B. E.: Brit. J. Exper. Path., 4, 283. 1923; Glenny, A. T., Pope, 

 C. G., and Waddington, H.: /. Path. £r Bad., 28, 291. 1925. 

 3 Glenny, A. T., and Allen, K.: ibid., 24, 61. 1921. 

 ■< E.g., Ramon, G.: Ann. de VInst. Pasteur, 39, i. 1925. 

 5 Moloney, P. J., and Weld, C. B.: Proc. Roy. Soc, Canada. 1925. 



