Continuous antilymphocyte serum therapy of AKR mice led to accelerated inortality from spontaneous lymphoma in one experiment. In a repeat experiment, accelerated splenic enlargement, presumably leukemic, occurred, but time of mortality from leukemia did not significantly differ from controls. Continuous antilymphocyte globulin therapy in AKR mice challenged with syngeneic lymphoma cells delayed mortality in mice given 10,000 or 1,000 tumor cells and prevented tumor growth in some animals inoculated with 100 tumor cells.
REATXf E S T WITH IIETEROLOGOUS ANTI-
T lymphocyte serum (ALS) or antilymphocyte globulin (ALG) has been shown to increase the incidence of tumors in animals injected with oncogenic viruses,le 2, 5-13-ZG and to enhalice the transplantability of solid tumor cells.3. 9, 22 These findings are of sign& cance with reference to the reports of the development of malignancies, usually lymphomas, in humans on immunosuppressive therapy, with or without ALS treatment.20 Paradoxically, ALS or ALG has been shown to inhibit syngeneic lymphoma cell grafts in certain strains of mice5 and has been used to tre;it human lymphoid leukemia.21, 24 In the present study, our purpose was to ascertain the effect of continuous ALS treatment on the development of spontaneous lymphoma and on the development of lymphoma resulting from graded syngeneic tumor cell challenge in AKR mice.
MATERIALS AND METHODS Specific pathogen-free AKR male mice23 were obtained from the colony .maintained by the Division of Experimental Biology, Baylor