Sensitization of Rabbits with Neoarsphenamin

Abstract

Although it has been demonstrated 1 , 2 , 3 that guinea pigs can be readily sensitized to neoarsphenamin, Frei 1 reported that he could achieve no hypersensitiveness to this drug in rabbits. In view of the findings of Sulzberger and Mayer 4 that guinea pigs bred in different countries reacted differently to the same brand of neoarsphenamin, experiments have been carried out to determine whether the rabbits bred in Peiping could be sensitized by this compound.

The brand of neoarsphenamin used throughout the work was that prepared by Hoechst Company, Germany, The ampules used for each experiment were from the same batch. 0.15 gm. of the drug was dissolved in 10 cc. of doubly distilled water and the solution diluted to 100 cc. with sterile normal saline. Only freshly prepared solutions were employed.

Observations have been made on 50 native bred adult male rabbits; individual body weights varied from 1350 to 2320 gm. All animals were albinos and the majority were of a delicate build with a slender head and moderately short ears. Thirty rabbits had been inoculated with Treponema pallidum from 4.5 to 34 months previously. At the time of the present experiments, only 4 showed active syphilitic lesions, the remainder being in the latent stage of the infection. Twenty-four hours before each experiment, the skin over both flanks was shaved; only ordinary soap was used. In each instance, the right flank was used for the first, and the left for the second injection, both being administered intradermally. The second or “testing” injection was made 4 weeks after the administration of the sensitizing injection. In the case of 8 normal and 12 syphilitic rabbits, 0.1 cc. was used for both the sensitizing and the testing doses.