Cyclophosphamide. I. Effects of survival and colony-forming cells in BDF1 L-1210-bearing mice.

A new technique is described in which L-1210 colony-forming cells and myelopoietic colony-forming cells can be assessed simultaneously from hemopoietic organs of L-1210-bearing mice. This technique was utilized to evaluate the effects of cyclophosphamide on the recovery of myelopoietic function in tumor-bearing mice. In general, changes in L-1210 colony-forming cells in bone marrows and spleens of cyclophosphamide-treated L-1210-bearing mice correlated with their mean survival time. Injection of L-1210 cells alone enhanced myelopoiesis in the spleen and injection of both cyclophosphamide and L-1210 cells resulted in a synergistic enhancement of myelopoiesis in the spleen. The results in this paper are also compatible with the hypothesis that the host defense system does regulate the growth of L-1210 cells in BDF mice.