Use of antilymphocyte globulin for leukemia induction in mice.

Biological activity of rabbit antimouse lymphocyte sera (ALS) and their IgG fractions was studied. Several ALS and ALG pools were cytotoxic in vitro for normal and leukemic mouse lymphocytes, causing temporary depletion of circulating leukocytes, prolongation of skin allografts, and progressive growth of L-1210/V leukemia transplanted across an H-2 barrier. As a rule, splenomegaly and a significant increase in the number of spleen cells were observed after i.p. injection of ALG. In experiments on the influence of prolonged treatment with ALG on tumor incidence in mice, one ALG pool appeared to be highly and repeatedly leukemogenic. The possible mechanism of leukemia induction by ALG was discussed.