Abstract
Summary
The spleen colony technique was used to test the in vitro effects of GPF (calf renal granulopoietic factor) and ESF (erythrocyte stimulating factor-rich anemic horse plasma) on the survival and differential colonizing potential of A/J mouse marrow cells in suspension culture. The quantitative survival of nucleated cells and transplantable colony forming units remained unaffected by the addition of either hemopoietin. Beginning at 1 hr and increasing progressively, the erythrocytic:granulocytic ratios of cultured marrow-derived spleen colonies shifted markedly in the direction of the hemopoietin-dependent cell line. Alternate theoretical explanations for this phenomenon are discussed.
This work was supported by U.S. Public Health Service Grants CA-07788 and CA-3713 and by Rockefeller Foundation Grant No. 67050. We thank Mr. P. B. Barsales, Mrs. I. M. Rao, Miss D. L. Raumaker and Mrs. E. W. Hopkins for their able technical assistance.
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