Susceptibility of the White Mouse to Tuberculosis

Abstract

The opinion that the mouse is practically immune or at least highly resistant to tuberculous infections seems to be quite generally expressed. Kettle 1 states that the tubercle bacillus is practically nonpathogenic to the mouse in the sense that it does not cause the necrotic or other lesions seen in susceptible animals and does not necessarily kill the animal. Trommsdorff 2 observed that mice were much more susceptible to bovine strains than to human strains when injected intravenously and suggested the possibility of using mice for type differentiation. His work was confirmed by Peters 3 and Binder. 4 Lange 5 used 3 human strains and 2 bovine strains of virulent tubercle bacilli for intravenous injections and observed no marked differences in the susceptibility of mice to the two types.

This report calls attention to the possibility of using white mice for certain types of work in the field of tuberculosis. The relatively low susceptibility of the mouse enhances its value in experiments where chronicity of the disease is desired. The rarity of spontaneous infection and the consistent results from intravenous administration of suitable doses suggest the possibility of a usefulness in virulence tests and possibly for experiments in immunity.

Recently isolated human and bovine strains and a virulent avian strain∗ were used for intraperitoneal and intravenous injections in full grown white mice. The expectation that mice would be resistant to infection led us to use unnecessarily large doses in the earlier experiments. Two or 3 weeks old cultures were emulsified by shaking with glass beads and the concentrations were made such that the desired dose was contained in 0.5 cc. of saline. In many cases the concentration was reduced by allowing the coarse clumps of bacilli to settle out so that the actual dose given was considerably less than that indicated in the table.