The simulation of bone marrow granulopoiesis of normal CBA mice in vitro and in vivo by serum obtained from leucophoretic rats.

The effect of leucophoretic serum (LS), obtained from rats with polyvinylpyrrolidone (PVP)-induced inflammation, on granulopoiesis in the bone marrow of normal CBA mice was studied. The following test systems were used: short term cultures (4 hr), diffusion chambers (8, 24, 48 and 72 hr) and in vivo assays (12, 24 and 48 hr). The results indicate that LS stimulates the proliferations of granulocytic cells by increasing the number of proliferative granulocytes in mitosis, as well as increasing the total number of proliferative granulocytes. LS did not appear to effect monocytes and other cell lines. It is concluded that a factor present in LS specifically stimulates the proliferation of granulocytic cells, both in vitro and in vivo.