Document 0708
 DOCN  M9460708
 TI    Cytokine circuits in brain. Implications for AIDS dementia complex.
 DT    9404
 AU    Benveniste EN; Department of Cell Biology, University of Alabama,
       Birmingham; 35294.
 SO    Res Publ Assoc Res Nerv Ment Dis. 1994;72:71-88. Unique Identifier :
       AIDSLINE MED/94159983
 AB    This chapter has summarized studies showing that cells of the immune
       system and glial cells of the CNS use many of the same cytokines as
       communication signals. Activated astrocytes and microglia are the
       principal sources of these cytokines in the CNS, although
       oligodendrocytes are capable of expressing IL-1 and TGF-beta. There is a
       complex circuitry of interactions mediated by cytokines, especially in
       the event of blood-brain barrier damage and lymphoid/mononuclear cell
       infiltration into the CNS. Infiltrating activated macrophages produce
       cytokines such as IL-1, TNF-alpha, and IL-6, which would trigger glial
       cells to produce their own cytokines. The activation of astrocytes and
       microglia to secrete proinflammatory cytokines such as IL-1, TNF-alpha,
       IL-6, and GM-CsF may contribute to the propagation of intracerebral
       immune and inflammatory responses initiated by immune cells, as well as
       enhancement of HIV-1 expression in the CNS. The cytokine cascades
       ongoing in the CNS could ultimately be suppressed due to the presence of
       immunosuppressive cytokines such as TGF-beta. Whether immune and
       inflammatory responses within the CNS are propagated or suppressed
       depends on a number of parameters, including (a) the activational status
       of these cells, (b) cytokine receptor levels on glial and immune cells,
       (c) the presence of cytokines with both immune-enhancing and
       immune-suppressing effects (IFN-gamma, IL-1, TNF-alpha, IL-6, TGF-beta,
       CsFs), (d) the concentration and location of these cytokines in the CNS,
       and (e) the temporal sequence in which a particular cell is exposed to
       numerous cytokines (see Fig. 1). The ultimate outcome of immunologic and
       inflammatory events in the CNS, as well as HIV expression, will be
       determined, in part, by an interplay of the above parameters.
 DE    AIDS Dementia Complex/*IMMUNOLOGY  Brain/*IMMUNOLOGY
       Cytokines/*PHYSIOLOGY  Granulocyte-Macrophage Colony-Stimulating
       Factor/PHYSIOLOGY  Human  Interleukin-1/PHYSIOLOGY
       Interleukin-6/PHYSIOLOGY  Neuroglia/IMMUNOLOGY  Support, Non-U.S. Gov't
       Support, U.S. Gov't, P.H.S.  Transforming Growth Factor beta/PHYSIOLOGY
       Tumor Necrosis Factor/PHYSIOLOGY  JOURNAL ARTICLE  REVIEW  REVIEW,
       TUTORIAL

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