Preventing or Reversing Immunosenescence

Can Exercise Be an Immunotherapy?

Adriana L de Araújo; Léia CR Silva; Juliana Ruiz Fernandes; Gil Benard

Disclosures

Immunotherapy. 2013;5(8):879-893. 

In This Article

Naive T Cells & Functional Alterations

The few studies that have addressed the function of residual naive T cells in the elderly point to considerable functional limitations with aging, including a reduced ability to produce IL-2 and to differentiate and expand into impaired effector cells, a decreased number of CD45RA+CD28+ T lymphocytes, telomere shortening and restriction of the of the TCR repertoire, when compared with the naive lymphocytes of young individuals.[26,54,55] Pfister et al. analyzed the impact of aging on naive T cells (CD4+ and CD8+) and found a significant decrease in CD45RA+CD28+ T cells in the elderly; however, the proliferative response remained unaffected.[26] Another report showed a decreased proliferative response to antigens, changes in surface molecule expression and intracellular signaling, and increased apoptosis rates.[56] Experimental studies have shown that prolonged survival in mice is associated with a high number of naive CD4+ T cells and a low number of memory CD8+ T cells, suggesting that the number of naive T cells could be used as an aging biomarker.[57] Thus, although further studies are required, it appears that disturbances in naive T-cell function are an important feature of immunosenescence.

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