Abstract
Susceptibility and resistance to a particular line of inoculable mouse leukemia may, for present purposes, be defined in terms of the presence or absence of conditions necessary for the survival of the active agent. A group of 11 such lines of agent, each of which originated in a different case of spontaneous lymphatic leukemia in a highly inbred strain of mice designated as C58, found the necessary conditions for survival in mice of the same strain. 1 Although different lines of agent can grow in the same pure bred strain of mice, these different lines do not all have the same requirements for survival, as has been shown by hybridization experiments. 2 The present report gives direct evidence of the specificity of requirements of different lines of agent, without the use of hybridization, by means of a new line that originated from a spontaneous case in another highly inbred strain of mice.
The new line of agent is designated line L. The spontaneous case that gave rise to this line was a mouse in strain 89; the line is carried in mice of this same strain. During the course of 13 transfers 75 mice of this strain have been inoculated. Of these all but 4 (94.6%) have died with unmistakable lesions of leukemia, mostly between the 15th and 25th days after inoculation. The agent of line L has been inoculated into 64 mice of strain Storrs-Little with completely negative results and into 82 mice of strain C58, of which all but one were negative.
The active agent of line I originated in a spontaneous case in strain C58 in April, 1929. It has now reached its 116th transfer. Barring experiments designed to study the nature of the agent, 859 mice of this strain have been so inoculated; all have proved susceptible with the exception of a single mouse whose identity is questionable.
Get full access to this article
View all access options for this article.