IN VIVO LOCALIZATION OF HETEROLOGOUS ANTI-LEUKEMIC CELL ANTIBODIES IN LEUKEMIC MICE AND THEIR EFFECT ON SURVIVAL PERIOD.

Abstract

There has been reported an increasing body of evidences suggesting the effectiveness of the immune therapy of leukemia. It is needless to say that anti-leukemic cell antibodies must suppress circulating leukemic cells as well as leukemic cells in the bone marrow and tissues, in order to induce the complete remission. However, until recently little attention has been directed to the in vivo localization of anti-leukemic cell antibodies in the bone marrow and tissues of leukemic animals, because of a lack of the reliable and reproducible method. Therefore, the in vivo bone marrow and liver localization of heterologous anti-leukemic cell antibodies in normal and leukemic mice was studied by means of 1131 labeled antibody. Anti-bone marrow antibodies agglutinated circulating leukocytes as well as leukemic ascitic tumor cells and anti-leukemic ascitic cell antibodies agglutinated not only leukemic ascitic tumor cells but also circulating normal leukocytes, indicating the presence of common antigens between normal leukocytes and leukemic ascitic tumor cells. Both I131 labeled anti-bone marrow antibodies and I131 labeled anti-leukemic ascitic cell antibodies were localized specifically in the bone marrow but not in the liver in normal mice. However, they were localized specifically in the bone marrow as well as in the liver in mice with leukemic ascitic tumor. These results suggest that anti-leukemic ascitic cell antibodies not only exert a cytotoxic effect on circulating leukemic cells but also are localized specifically in the bone marrow and tissues and exert a cytotoxic effect on leukemic cells in them. The administration of I131 conjugated anti-leukemic ascitic cell antibodies containing a large amount of 1131 to mice with leukemic ascitic tumor resulted in a marked decrease of the percentage of circulating leukemic cells and in a slight prolongation of the survival period.