Age-related effects in T cell activation and proliferation.
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.
Song
L
L
Clinical Immunology Section, National Institute on Aging, NIH, Baltimore, MD 21224-2780.
Kim
Y H
YH
Chopra
R K
RK
Proust
J J
JJ
Nagel
J E
JE
Nordin
A A
AA
Adler
W H
WH
D000328:Adult; D000368:Aged; D000375:Aging / Q000276:immunology*; D000818:Animals; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis; D008137:Longitudinal Studies; D008213:Lymphocyte Activation / Q000502:physiology*; D051379:Mice; D008875:Middle Aged; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis; D013601:T-Lymphocytes / Q000276:immunology*
D007376:Interleukin-2; D015375:Receptors, Interleukin-2