Pure and mixed erythroid colony formation in vitro stimulated by spleen conditioned medium with no detectable erythropoietin.

Abstract

Cells from CBA fetal mouse liver formed pure or mixed erythroid colonies in semisolid agar culture after stimulation by medium conditioned by pokeweed mitogenstimulated mouse spleen cells. In general shape, the erythroid colonies resembled typical 7-day single or multiple (burst) colonies. However one-third to one-hal containe, in addition to erythroid cells, macrophages and neutrophils and, less commonly, megakaryocytes or eosinophils. Culture of micromanipulated single colony-forming cells showed these erythroid colonies to be clones. Colony-forming cells declined in frequency with advancing fetal age, but low numbers were detectable in adult bone marrow. Assays of spleen conditioned medium in polycythemic mice failed to detect erythropoietin; the cloning system may detect a fetal type of erythropoietinindependent, erythropoietic cell since few were detected in adult marrow.

Effects of Burst-promoting Activity and Erythropoietin from Human Urine on Erythroid Burst Forming Units in Human Peripheral Blood

“…Mouse spleen conditioned medium (MSCM) was prepared by the method of Johnson and Metcal [29) BPA assay for purification. BPA was assayed with a minor modification of the method described by Iscove et al,3D) throughout the purification of BPA.…”

Donald Metcalf AC. 26 February 1929 — 15 December 2014

“…Antony Burgess went on with Metcalf to purify GM-CSF to apparent homogeneity from mouse-lungconditioned medium by 1977 (13). In 1976 Burgess invited Nicos Nicola (figure 5) (who had also trained with Syd Leach) to join him and Metcalf in the biochemical characterization of the CSFs.…”

Cytokine Regulation of Early Lymphohematopoietic Development

“…Since semisolid culture assays for murine [17,18] and human [19] multipotential progenitors had been reported, a number of investigators had observed the presence of lymphocytes or precursors of lymphocytes in murine and human multilineage colonies. However, the clonal origin of these colonies was never firmly established in these studies.…”