Drugs.Solutionsof Cyclo,obtainedfrom MeadJohnson

We previously reported a successful model for treatment of BW 5147 leukemia in AKR mice by adoptive immunother apy using allogeneic spleen cells from C57BL/6 mice. The leukemia cells were given 3 days before initiation of ther apy. Graft-versus-host reaction was prevented by treatment with spleen cells from a second allogeneic strain (CBA), followed by cyclophosphamide and syngeneic spleen cells. We now show that it is not necessary to use syngeneic spleen cells in the final transplant since H-2-compatible, allogeneic CBA cells are as effective. In addition, it is possi ble to initiate successful therapy 5 days after leukemia im plantation providing that the initial cyclophosphamide, given in two doses of 100 mg/kg each and spaced 7 days apart, is administered prior to establishment of graft-versus host reaction. Higher single doses of drug were followed by fatal graft-versus-host disease.