Age-Specific T Cell Homeostasis
Multiples defects affect adaptive immunity during aging: T cell production (both at thymic and peripheral sites), T cell activation (including TCR sensitivity, proliferation, and differentiation), T cell functions, and T cell survival. Most of these defects directly impact T cell homeostasis. Indeed T cell homeostasis refers to the maintenance of steady state in the body and the physiological processes through which they are regulated. This mechanism ensures a close equilibrium between T cell production and death, two aspects that are drastically affected during aging.
The aim of this chapter is to review the changes in T cell homeostasis developing during aging. We will first review the main homeostatic mechanisms that have been described so far in adult individuals. In a second part, we will document the age-related events that crucially impact T cell homeostasis and the resulting effects on peripheral T cell pools. Finally, the potential benefits of regenerative therapies aiming to restore T cell homeostasis will be discussed.
KeywordsT lymphocytes Viral infection Aging IL-7 CD8 expansion
Hematopoietic stem cells
T cell repertoire
Thymic epithelial cell
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