CHARACTERIZATION OF COLONY-STIMULATING ACTIVITY PRODUCED BY HUMAN MONOCYTES AND PHYTOHEMAGGLUTININ-STIMULATED LYMPHOCYTES

  • 1 January 1977
    • journal article
    • research article
    • Vol. 50  (5) , 811-821
Abstract
Human colony-stimulating activity (CSA) may support the proliferation of both human and murine granulocyte-macrophage progenitor cells (CFU-C) or, in the case of human urinary CSA, may only stimulate murine bone marrow CFU-C. CSA produced in the culture media of monocytes and macrophages and phytohemagglutinin-stimulated lymphocytes from human peripheral blood was characterized for both human and mouse marrow CFU-C stimulating activities. During the initial phase of a long-term culture of monocytes, both human- and mouse-active CSA (MnCM-HM) were produced. In later phases of culture, only mouse-active CSA (MnCM-M) was produced. Fractionation on Sephadex G-150 revealed 2 functionally distinct species from MnCM-HM and lymphocyte conditioned medium, a high MW factor (MW > 150,000) which stimulated mouse but not human colony formation, and a low MW species (MW 25,000-35,000) which was active against both mouse and human target cells. MnCM-M revealed only 1 high MW species (> 150,000), active only on mouse marrow. The possible biologic significance of such an activity is discussed.

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