Heterologous Antiserum to Chemically Induced Rat Non-T, Non-B Leukemia and Its Application to Characterization of Rat Leukemias¹

Antisera to the 1-butyl-1-nitrosourea-induced “non-T, non-B” rat leukemia line DBLA-6 were raised in rabbits. Following absorption with syngeneic hepatoma cells, the antisera were very similar in specificity to antisera raised to rat Thy-1 antigen. Anti-DBLA-6 serum was cytotoxic in the presence of complement against 70 to 90% of thymocytes and 40 to 50% of neonatal spleen cells. In contrast, no significant cytotoxicity was observed against cells from bone marrow, lymph node, spleen, and peritoneum. An absorption test revealed that an antigen recognized by anti-DBLA-6 serum was present in brain tissue but absent in liver and kidney tissues. Nineteen rat leukemias and lymphomas were divided into six groups based on antigenic and morphological characteristics and the presence of receptor for guinea pig red blood cells. These tumors were investigated for the presence of the antigen recognized by anti-DBLA-6 serum. Of the leukemias and lymphomas studied, anti-DBLA-6 serum reacted with all thymic (Group 1) and extrathymic (Group 2) lymphomas and unclassified leukemias (Groups 3 and 4), while all myelogenous leukemias (Group 5) and erythroleukemias (Group 6) were negative. The position of leukemias and lymphomas reactive with anti-DBLA-6 serum in the lymphocyte maturational pathway is discussed.