Effect of haematopoietic cell growth factor on intracellular ATP levels.

Growth and development of haematopoietic cells in vitro require the presence of specific regulatory molecules. Some of these molecular species appear to have a broad specificity, being able to promote the proliferation and differentiation of multipotential cells, as well as megakaryocytic, erythroid and granulocytic-progenitor cells. Such factors are present in medium conditioned by the growth of lectin-stimulated mouse spleen cells or WEHI-3 myelomonocytic leukaemia cells (WEHI-CM). Using WEHI-CM, we and other have been able to obtain permanently growing, non-leukaemic cell lines of a granulocytic or mast cell nature. Significantly, we have found that the factor in WEHI-CM necessary for the growth of these cells has co-purified with the multi-lineage stimulating activity present in WEHI-CM, suggesting that one molecule may be concerned in the development of multiple cell types. We have now used these cells to investigate the mode of action of this haematopoietic cell growth factor and have found that the requirement of this factor for survival and growth may lie in its ability to modulate ATP levels within the cells.