Treatment with BAT monoclonal antibody decreases tumor burden in a murine model of leukemia/lymphoma

BAT is a monoclonal antibody produced against membranes of Daudi cells that induces anti-tumor activity in mice against a variety of solid murine and human tumors, mediated by its immune stimulatory properties on murine and h uman lymphocytes. The present study analyzes the effect of BAT on leukemia/ lymphoma using the BCL1 model of leukemia/lymphoma in BALB/C mice. BAT anti body binds to BCL1 leukemia cells and recognizes a 48 kDa protein similar t o the antigen on Daudi cells. Mice inoculated with leukemia cells were trea ted either by direct BAT injections or by adoptive transfer of lymphocytes from BAT-injected mice. Administration of BAT monoclonal antibody was eithe r once, on day 14, or daily on days 10-13 post tumor inoculation. A single injection of BAT resulted in reduction of peripheral blood tumor cells, how ever additional injections further decreased the tumor cell number reaching a 95-fold reduction on day 20 post tumor inoculation. Antitumor effect was also obtained when animals were injected with splenocytes from BAT-treated donor mice, A significant prolongation of survival of BAT-treated mice was observed although with no cure. The results of this study indicate that BA T might be used for reducing the tumor burden in leukemia for immunotherapy and in combination with other treatment modalities.