       Document 0454
 DOCN  M9620454
 TI    Cell surface morphology identifies microglia as a distinct class of
       mononuclear phagocyte.
 DT    9602
 AU    Giulian D; Li J; Bartel S; Broker J; Li X; Kirkpatrick JB; Department of
       Neurology, Baylor Center for AIDS Research, Baylor; College of Medicine,
       Houston, Texas 77030, USA.
 SO    J Neurosci. 1995 Nov;15(11):7712-26. Unique Identifier : AIDSLINE
       MED/96066793
 AB    To investigate differences among brain-derived microglia and other
       classes of immune cells, we compared the morphologies and growth
       properties of mononuclear phagocytes isolated from tissues of the
       newborn rat. Scanning EM shows that microglia from postnatal rat brain
       are covered with spines (typically > 20 per cell body) in a distinctive
       manner which contrasts the smooth surfaces of bone marrow cells and the
       ruffled surfaces of tissue macrophages from spleen, liver, and
       peritoneum. The spine-bearing surface of microglia is a specific cell
       marker, for it does not change with age or after exposure to cytokines
       or other immunostimulants. Approximately 99% of mononuclear phagocytes
       cultured from normal adult rat brain are spinous microglia. Five days
       after injury to rat brain, cells at sites of Wallerian degeneration are
       essentially all spinous ones while nearly 30% of cells found within
       areas of infarction or penetrating trauma are invading macrophages. In a
       similar way, nearly all cells isolated from normal, postmortem adult
       human brain are spine-bearing microglia (> 99% homogeneity). Brains from
       patients with amyotrophic lateral sclerosis contain only spinous
       microglia whereas cells from HIV-1 infected brains include significant
       numbers of invading ruffled macrophages. Cultured microglia, unlike
       cultured bone marrow precursors, monocytes, or tissue macrophages,
       spontaneously develop long, thin processes that extend hundreds of
       microns in length. Microglia retract these processes after exposure to
       fetal bovine serum, laminin, or such immunostimulants as recombinant
       murine interferon gamma (rmIFN gamma) and lipopolysaccharide. Of all
       types of mononuclear phagocytes tested, only microglia differentiate
       into quiescent ramified cells when in contact with astrocytes. Thus,
       microglia represent a unique class of cell maintained, in part, by
       astroglia as dormant, ramified mononuclear phagocytes in mature CNS.
       Application of cell surface criteria described here will allow study of
       distinct populations of mononuclear phagocytes associated with
       neurologic disorders.
 DE    Adult  Animal  Animals, Newborn  Astrocytes/PHYSIOLOGY  Brain/CYTOLOGY
       Cattle  Cell Communication  Cell Differentiation  Cell
       Membrane/ULTRASTRUCTURE  Cell Survival  Cells, Cultured  Human  Mice
       Microglia/CYTOLOGY/PHYSIOLOGY/*ULTRASTRUCTURE  Microscopy, Electron,
       Scanning  Microscopy, Fluorescence  Phagocytes/*ULTRASTRUCTURE  Rats
       Support, Non-U.S. Gov't  Support, U.S. Gov't, P.H.S.  JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).

