KINETICS AND ULTRASTRUCTURAL STUDIES OF THE INDUCTION OF RAT ALVEOLAR MACROPHAGE FUSION BY MEDIATORS RELEASED FROM MITOGEN-STIMULATED LYMPHOCYTES

Google Scholar
  • 1 January 1981
    • journal article
    • research article
    • Vol. 103  (2) , 234-246
Abstract
[Cells of the macrophage-histiocyte series are important in host defense against infections and neoplasms.] Treatment of F344 rat alveolar macrophages (AM) in vitro with cell-free supernatant fluids obtained from concanavalin (Con) A-stimulated syngeneic lymphocytes induced extensive fusion. The lymphokine responsible for the fusion of AM (but not other cells) is referred to as AM fusion factor (Con-A-MFF). Fusion is dependent on the dose of Con-A-MFF and the population density of AM cultures and occurred 10 h after Con-A-MFF was added to cultures of normal AM. Con-A-MFF must interact with AM for more than 8 h before full expression of fusion is reached at 24 h. Using a technique allowing for sequential scanning to transmission electron microscopy analysis of cells, the relationship of the morphologic characteristics of the surface and the internal structure of cells fusing to form multinucleate giant cells (MGC) was studied. The process of AM fusion begins with AM aggregation, followed by interdigitation of cell processes. Serial sections of MGC showed lysosomes associated with remnants of plasma membrane in the cytoplasm. The MGC contained numerous organelles associated with increased secretory activity of cells.