Variation of Response to Infection With Treponema Pallidum Between an Albino and a Brown Breed of Rabbit

Abstract

This experiment was undertaken for the purpose of comparing the course of syphilitic infection in 2 different breeds of rabbit, one a pure albino and the other a brown variety, inoculated under identical conditions with a virulent strain of Treponema pallidum. The animals were normal young males. The body weight of the albinos varied from 1430 to 1860 gm., that of the brown rabbits from 1340 to 2130 gm. During the experiment they were housed under uniform conditions in a light and well ventilated room, and fed on the same diet.

Experimental. The strain of Treponema pallidum used was that originally isolated by Nichols 1 from the spinal fluid of a patient with syphilitic neurorecurrence. This strain, now 17 years old, has had many passages through rabbits and has attained a high degree of virulence for this animal. The strain was brought to China in September, 1927. The immediate source of virus for this experiment was one of the third group of rabbits through which the strain had passed in this country. This animal was a brown breed and showed clinical evidence of orchitis 28 days after inoculation. When the orchitis was progressing, the right testis was excised under ether anesthesia, finely minced with scissors, and ground up in a sterile mortar with sterile physiologic sodium chloride solution. Of the more fluid portion of this emulsion, 0.3 cc. was inoculated into the right testis of each of 8 albino and 9 brown rabbits. The inoculations were all made on February 24, 1928. The emulsion contained from 2 to 3 actively motile organisms to the microscopic field. One animal in each group of rabbits died of pulmonary disease soon after inoculation.