An In Vitro Study of Antileukemic Serum

1. A rabbit anti-DBA₂-mouse-induced lymphogenous leukemia serum was prepared that contained antibodies to normal lymphocytic and to leukemic lymphocytic antigens, as determined by the complement fixation test of Thornton and his associates.

2. When this antiserum was incubated with normal lymphocytic antigen, all of its complement fixing activity was removed except that which reacted with the leukemic tissue. It appears that an antibody or group of antibodies was produced which was specific for this leukemia.

3. An antiserum to lymphogenous leukemia, induced in DBA₂ mice, given prophylactically or therapeutically, did not significantly protect other DBA₂ mice that had been inoculated with a transplantable leukemia of the same cell type.

4. The failure to induce leukemia in young, DBA₂ female mice by painting them with 20-methylcholanthrene in benzene is reported.