Prolonged remissions of lymphatic leukemia in DBA-2 mice induced with endogenously produced lactate dehydrogenase antibody.

Induction of lactic dehydrogenase (LDH) antibody with porcine LDH in L1210 leukemia-bearing DBA/2 mice can induce remissions of the disease. The concurrent, limited use of a cytotoxic agent (azathioprine) in combination with LDH has been investigated and found to be advantageous in terms of obtaining a greater number of prolonged remis sions (over 150 days) than does the use of LDH alone. The protocols developed used 12 to 25 DBA/2 mice, inoculated with either 200 or 2000 L1210 tumor cells, per group. Animals were given injections of from 92 to 275 pmoles of LDH in adjuvant. Some groups received injec tions postinoculation only, others both preand postinoculation. Azathioprine (two injections) was added to some of the treatment regimens. Control groups comprised un treated L1210-inoculated animals, L1210-inoculated ani mals treated with azathioprine only, and animals treated preand postinoculation with ovalbumin (788 to 1480 pmoles) and porcine albumin (217 to 650 pmoles), respec tively. Untreated L1210-bearing mice die of leukemia 10 to 12 days postinoculation. Prolonged survival times (over 150 days) in the other groups ranged from 18% for azathioprine control groups, 0 to 10% for various albumin and albumin plus azathioprine combinations, 0% for LDH treatment given postinoculation; 0 to 43% for LDH given preand postinoculation, and 92% in one experiment in which azathioprine (two injections) was added to a preand post-LDH injection schedule. Survival rates in LDH experi ments appeared to correlate with the pattern of anti-LDH engendered in a given experiment.