Modification of Skin Sensitivity to Neoarsphenamin in Rabbits Treated with Potassium Iodide and Bromide

Abstract

It has been demonstrated^{1, 2, 3} that a nonspecific positive luetin reaction can be produced in the human subject and animals by the administration of potassium iodide. The object of the present study was to ascertain whether or not potassium iodide and bromide are capable of exerting a similar influence on the skin hypersensitiveness to neoarsphenamin in rabbits.

This work included 2 experiments, involving 76 adult male albino rabbits. Twenty-four of these animals which had been inoculated with Treponema pallidum from 5 to 8 months previously, were distributed in both experiments and were all in the latent stage of the infection at the time of the experiments. The neoarsphenamin solution was prepared and the rabbits were shaved according to the methods described previously. 4 The brand of neoarsphenamin used was that prepared by Hoechst Company, Germany, and the ampoules employed were always from the same batch. The rabbits were sensitized and tested with 0.2 cc. of freshly prepared 0.15% neoarsphenamin in normal salt solution. The right flank of the animal was used for the sensitizing injection and the left for the testing injections, all being intradermal. The hypersensitive reaction, which was manifested as redness and infiltration, was read 24 hours after injection, the size of the involved skin area ranging from 1 to 3 cm. in diameter.

In the first experiment, 42 rabbits were used and in the second one, 34 rabbits. Five weeks after the animals had been sensitized, they were tested for hypersensitiveness (first test). As shown in the accompanying table, the animals of each experiment were then divided into 3 groups, each of which included both hypersensitive and non-sensitive rabbits of about equal number. The first group of each experiment was used as control and the others as test groups.