EFFECT OF HEMATOPOIETIC GROWTH-FACTORS ON HUMAN BLOOD MONOCYTES MACROPHAGES IN IN-VITRO CULTURE

The production of mature monocytes/macrophages is regulated by a group of hematopoietic growth factors, or colony-stimulating factors (CSF). We investigated the in vitro effect of human hematopoietic growth fac tors on human blood monocyte/macrophage differentiation and proliferat ion in short- and long-term in vitro cultures. The addition of macroph age CSF, granulocyte-macrophage CSF, and granulocyte CSF and interleuk in-6 and interleukin-3 growth factors to monocyte/macrophage cultures induced morphological changes in cultured cells, including enhancement of cell growth and the formation of multinucleated giant cells, spind le-like cells, and fibroblast-like cells. In addition, CD4 and HLA-DR antigen expression was down regulated by the addition of growth factor s without a change in the expression of other surface antigens, includ ing CD3, CD11B, CD14, CD15, NK H1, and B1. The proliferating cell nucl ear antigen was not detected in growth factor-treated nonadherent mono cytes/macrophages in long-term cultures. Bromodeoxyuridine was incorpo rated in the adherent monocytes/macrophages, and intense staining in t he small rounded cells which occur above the adherent cells in these c ultures was observed after a 72-h pulse, indicating that monocytes/mac rophages are slowly dividing cells.