[HTML][HTML] Convergence of innate and adaptive immunity during human aging

BI Pereira, AN Akbar - Frontiers in immunology, 2016 - frontiersin.org
BI Pereira, AN Akbar
Frontiers in immunology, 2016frontiersin.org
Aging is associated with profound changes in the human immune system, a phenomenon
referred to as immunosenescence. This complex immune remodeling affects the adaptive
immune system and the CD8+ T cell compartment in particular, leading to the accumulation
of terminally differentiated T cells, which can rapidly exert their effector functions at the
expenses of a limited proliferative potential. In this review, we will discuss evidence
suggesting that senescent αβCD8+ T cells acquire the hallmarks of innate-like T cells and …
Aging is associated with profound changes in the human immune system, a phenomenon referred to as immunosenescence. This complex immune remodeling affects the adaptive immune system and the CD8+ T cell compartment in particular, leading to the accumulation of terminally differentiated T cells, which can rapidly exert their effector functions at the expenses of a limited proliferative potential. In this review, we will discuss evidence suggesting that senescent αβCD8+ T cells acquire the hallmarks of innate-like T cells and use recently acquired NK cell receptors as an alternative mechanism to mediate rapid effector functions. These cells concomitantly lose expression of co-stimulatory receptors and exhibit decreased T cell receptor signaling, suggesting a functional shift away from antigen-specific activation. The convergence of innate and adaptive features in senescent T cells challenges the classic division between innate and adaptive immune systems. Innate-like T cells are particularly important for stress and tumor surveillance, and we propose a new role for these cells in aging, where the acquisition of innate-like functions may represent a beneficial adaptation to an increased burden of malignancy with age, although it may also pose a higher risk of autoimmune disorders.
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