Λεξικό .. Anergy

Anergy

Term synonymous to immunosuppression. The inability to react to a battery of common skin test antigens [1]. Anergy is defined as either specific resistance of the cell to stimulation or to functional inactivation and has some appeal as a mechanism for the induction and maintenance of peripheral tolerance. Considerable research has been dedicated to investigating the existence and potential of anergy in immune regulation. Anergy is induced in T cells following interaction with other T cells and antigen in the absence of costimulation [2, 3].

In addition to the interaction between the TCR on T cells and the major histocompatibility complex (MHC) bound to peptide antigen on the antigen-presenting cell (APC) (signal 1), T cells require a second, costimulatory signal to become activated. Processes that block costimulation in the presence of antigen lead to anergy [4]. Classically, anergic cells are unable to proliferate in the absence of IL-2 and fail to secrete cytokines [although they can, in some circumstances, retain a T helper (Th2)-type phenotype and secrete IL-4 and IL-5 [5]. However, anergic cells can sometimes inhibit naive and primed T cells in an antigen-specific manner. It is suggested that this occurs via competition of the anergic cells with non-anergic cells for cytokines (e.g. IL-2) and cell-surface area of APCs [6].

References

1. Stites, D.P.: Clinical Laboratory Methods of detection of Cellular Immune Function. In Basic and Clinical Immunology, ed. by Stites D.P. et al, 4th ed. Lange, 1982:367.

2. Lafferty, K.J. and Woolnough, J. (1977) The origin and mechanism of the allograft reaction. Immunol Rev 35, 231-262,

3. Lamb, J.R. et al. (1983) Induction of tolerance in influenza virus-immune T lymphocyte clones with synthetic peptides of influenza hemagglutinin. J Exp Med 157, 1434-1447.

4. Gajewski, T.F. et al. (1994) "Anergy" of TH0 helper T lymphocytes induces downregulation of TH1 characteristics and a transition to a TH2-like phenotype. J Exp Med 179, 481-491.

5. Schwartz, R.H. (1990) A cell culture model for T lymphocyte clonal anergy. Science 248, 1349-1356.

6. Marusic, S. and Tonegawa, S. (1997) Tolerance induction and autoimmune encephalomyelitis amelioration after administration of myelin basic protein-derived peptide. J Exp Med 186, 507-515.