Cytochemical characteristics of leukopoietic differentiation in murine erythroleukemic (Friend) cells.

The 3BM-78 murine Friend erythroleukemia cell line was obtained by in vitro transformation of bone marrow cells of DBA/2J mice by the polycythemic Friend virus complex. Thirty-five subclones have been isolated and tested for their ability to express various markers of blood and bone marrow cells. Upon dimethyl sulfoxide treatment, the cells differentiated along the erythroid pathway as shown by morphological evidence and by their increased synthesis of hemoglobin and spectrin. In addition, a high proportion of dimethyl sulfoxide-induced cells stained positive for specific esterase, a marker characteristic of granulocytic cells. Of these cells, about 20% stained positive for both hemoglobin-peroxidase and specific esterase. Analysis of the subclones showed that the expression of these markers for erythroid and leukopoietic differentiation was uncoordinated. Further dissection of expression was obtained by the use of two potent tumor promoters, 12-O-tetradecanoylphorbol-13-acetate and phorbol-12,13-benzoate, which in general inhibited specific esterase more than hemoglobin peroxidase expression. Inhibition was related to the structure of the phorbol diester and was unrelated to toxicity. No evidence was found for other markers characteristic of different pathways of differentiation, such as Fc and C3 receptors, cell surface immunoglobulins, theta antigen, or the capacity to phagocytose inert particles. All cells stained positive for nonspecific esterase activity in both the presence and the absence of dimethyl sulfoxide. This staining was only partially fluoride sensitive. In unstimulated cultures, a few cells also reacted for myeloperoxidase, Sudan black staining and, very rarely, alkaline phosphatase staining. These findings support the view that 3BM-78 cells are leukemic cells which, despite a prevalent commitment to erythroid differentiation, retain the genetic determinants for some traits of leukopoietic differentiation. These traits may be expressed under suitable culture conditions.