Song L, Kim Y H, Chopra R K, Proust J J, Nagel J E, Nordin A A, Adler W H
Clinical Immunology Section, National Institute on Aging, NIH, Baltimore, MD 21224-2780.
Exp Gerontol. 1993 Jul-Oct;28(4-5):313-21. doi: 10.1016/0531-5565(93)90058-l.
Age-associated thymic involution manifests its effects in a variety of ways that are related to a loss of T cell function. These include the appearance of a non-functional subset of T cells that increase in representation with age. Moreover there is a loss of T cell proliferative ability, a decline in the synthesis and release of interleukin-2 (IL-2), a decline in the ability of the T cell to express the IL-2 receptor, and a loss of control activity. This loss of control is demonstrated by the age-related appearance of autoantibodies and an increase in the elaboration of inflammatory cytokines such as TNF, IFN, IL-6, and TGF. A major part of the basis for the loss of T cell function is an inability of the T cell to respond to activation signals that are transmitted through the membrane binding of specific stimulatory signals. Transduction events, differentiation signals, and a loss of control mechanisms are all parts of a complicated picture of age-related immune deficiencies.
