New application of a stabilized active cyclophosphamide derivative (mafosfamide, ASTA Z 7654)--immunogenic properties of lymphatic leukemia L 1210 cells treated in vitro with the drug.

Lymphatic leukemia L 1210 cells were treated in vitro with various concentrations of Mafosfamide--a stabilized active derivative of cyclophosphamide (4-hydroxycyclophosphamide). L 1210 cells treated with Mafosfamide (L 1210-MAF cells) were used for vaccination of semisyngeneic CD2F1 mice against L 1210 leukemia. These cells do not grow in vivo but are viable in the test with trypan blue. L 1210-MAF cells, obtained by treatment of L 1210 cells two times with 50 micrograms/ml or 100 micrograms/ml of Mafosfamide, and injected into the mice induced resistance against L 1210 leukemia in these animals. L 1210 cells treated two times with higher concentration of Mafosfamide (200 micrograms/ml or 400 micrograms/ml) did not give this effect.