[On the mode of action of heterologous antileukemic sera. Growth of syngeneically transplanted leukemia cells on serum treated neonatally thymectomized mice (author's transl)].

A heterologous antiserum against a Nitrosomethylurea--induced mouse leukemia prevented the outgrowth of syngeneically transplanted leukemia cells in neonatally thymectomized mice. After subcutaneous challenge with 50 000 leukemia-ascites cells thymectomized CBA mice at the age of 8 weeks were given 5 intraperitoneal injections each of 0,1 ml of the heterologous serum. While the antileukemic serum protected 9 out of 11 mice all of the 11 mice treated with normal rabbit serum developed a tumor.