mTOR signaling promotes a robust and continuous production of IFN-γ by human memory CD8+ T cells and their proliferation.

Human CD8(+) T cells are functionally heterogeneous and can be divided into phenotypically and functionally distinct subsets according to CCR7 and CD45RA expression levels. Among these, CCR7(low) CD45RA(low) effector memory CD8(+) T cells (Tem) and CCR7(low) CD45RA(high) CD8(+) T cells, which are designated as Temra and considered to be terminally differentiated cells, are Ag-experienced T cells but show different functionalities. Here, we show that, while Tem proliferate vigorously and produce IFN-γ persistently and robustly, Temra proliferate poorly and lose the ability to produce IFN-γ over time after TCR stimulation.