Studies on Mouse Leukemia II. Hereditary Susceptibility to Inoculated Leukemia

Abstract

In previous communications2 we have reported the following points: (1) The existence of an inbred strain of mice, designated as C 58, in which spontaneous lymphatic leukemia, in its somewhat varied manifestations, appears in a high proportion of animals at various ages after six months. (2) The transmissibility of this condition to young animals of the same strain by inoculations with tissue suspensions, and the establishment, from different spontaneous cases, of lines of inoculated leukemia, by successive transfers from the inoculated mice. (3) The appearance of characteristic differences in the response of the host animal called forth by different lines of inoculated leukemia. The present paper deals primarily with differences in response to inoculations within the same line of inoculated leukemia, due to differences in the host animals. Susceptible and Resistant Strains All the mice in the susceptible strain, with the rarest exceptions, die with leukemia within two weeks of inoculation. Fully as important for present purposes was the discovery of another inbred strain of mice (StoLi) none of which dies of leukemia after inoculation (200 having been tested). Crosses and backcrosses between these two strains were made, and the susceptibility of the offspring (mostly within their second month) was tested by inoculations. In making these inoculations all the mice receiving inoculant from a single donor were called an experiment. Each experiment included: (1) three to five mice from the susceptible strain to provide donors for the next experiment and controls for the inoculant; (2) in many cases a set of mice from the resistant strain, as well as (3) first generation hybrids and (4) backcross animals, according to the mice of the right age available at the time. Two lines of inoculated leukemia, designated by the letters I and A, were used in the tests.