Age-associated changes in the frequency of naïve, memory and effector CD8+ T cells.

We investigated age-associated changes in the frequency of CD8+ T cell subsets with different functions. Based on expression of CD45RA and CCR7, naïve (CD45RA+ CCR7+), central memory (CM, CD45RA- CCR7+), effector memory (EM, CD45RA- CCR7-) and effector (CD45RA+ CCR7-) CD8+ T cells were identified in peripheral blood from healthy young (n = 17) and elderly (n = 17) people using flow cytometry. The elderly had a decreased frequency of naïve and an increased frequency of EM and effector CD8+ T cells compared to the young. However, both groups had a similar frequency of CM cells. These findings suggest that age-associated changes in CD8+ T cell subsets occur, which could be a potential explanation for altered CD8+ T cell function in the elderly.