Observations on the Transmissibility of Lymphoid Leucemia of Mice. ∗

Abstract

Two spontaneous cases of lymphoid leucemia of mice have been observed in a stock of about 300 mice (over 8 months of age) designated as strain A. The systemic enlargement of all superficial lymph nodes drew attention to this condition. The white blood count was 157,000 in one case and 315,000 in the other; in both, the spleen was very much enlarged and extensive lymphomatous infiltrations were found in the liver. Both cases have been successfully transmitted to normal mice of the same strain and of another strain named R. In about 800 mice of the latter strain, which are still alive, and in about 100 autopsied cases of the same strain (above the age of 8 months) no leucemia or lymphosarcoma has been found. Table I is a summary of the first 7 transmissions including first passages from the spontaneous cases and 2 second, one third and one fourth passage from the first case, and one second passage from the second case.

Lymph nodes or lymph nodes and spleen from leucemic mice were cut up with a small scissors and Locke solution was added drop by drop. After filtration through a small piece of cotton the turbid solution containing about 40,000 to 150,000 lymphocytes per cm. was injected in amounts of 0.1 to 0.2 cc. The blood of a leucemic mouse, injected into the tail veins of 5 mice caused leucemia in 3 and lymphosarcoma in one.

The incubation period of the instances of leucemia under observation varied between 14 and 33 days, the average being 26 days. The leucocyte count of the transmitted cases at the height of the leucemia varied between 239,000 and 570,000.

The older literature on attempts to transmit leucemia has been reviewed by Opie.