Document 0778
 DOCN  M9460778
 TI    Involution of the thymus revisited: immunological trade-offs as an
       adaptation to aging.
 DT    9404
 AU    Aronson M; Department of Histology and Cell Biology, Sackler School of;
       Medicine, Ramat Aviv, Tel Aviv, Israel.
 SO    Mech Ageing Dev. 1993 Nov;72(1):49-55. Unique Identifier : AIDSLINE
       MED/94158366
 AB    An attempt was made, in previous theories, to find a unifying
       explanation for two phenomena of thymic involution: stress-induced
       reversible involution and age-related irreversible involution. It was
       postulated that in both cases involution is beneficial to the organism,
       as it serves to reduce the dangers of autoimmune reactions. The modified
       theory proposed here: (a) relates to the suggestions of I.R. Cohen and
       D.B. Young (Immunol. Today, 12 (1991) 105-109) and to those of S.
       Avrameas Immunol. Today, 12 (1991) 154-158) as to the usefulness of
       autoantibodies to the organism; (b) emphasizes the fact that self
       components undergo continuous changes throughout the life cycle of the
       organism, which in turn necessitates continuous adaptations to prevent
       autoimmune damage; (c) stresses the relevance of these adaptations to
       the process of natural selection; (d) brings experimental evidence to
       the effect that thymic involution will reduce the danger of autoimmune
       damage; and (e) suggests that the adaptations required to prevent
       autoimmune reactions with aging entail immunological compromises or
       trade-offs. These measures may by themselves cause autoimmune diseases,
       result in reduced resistance to neoplasia and to infectious diseases,
       particularly viral ones, and in accelerated aging.
 DE    *Adaptation, Physiological  Aging/*PHYSIOLOGY  Animal  Antibody
       Formation  Autoantibodies/IMMUNOLOGY  CD4-CD8 Ratio  Human  Immunologic
       Memory/IMMUNOLOGY  Rats  Rats, Inbred BUF
       T-Lymphocytes/CYTOLOGY/IMMUNOLOGY  Thymus Gland/*IMMUNOLOGY/*PHYSIOLOGY
       JOURNAL ARTICLE

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