Persistent viral infections, inflammatory syndromes and ageing all induce the accumulation of highly differentiated CD45RA re-expressing memory T cells. These cells increase during ageing, especially in individuals who are infected with cytomegalovirus (CMV). These cells have decreased proliferative capacity, increased activation of senescence signalling pathways and greater susceptibility to apoptosis in vitro. However these cells are capable of multiple effector functions and thus bear all the hallmarks of short-lived effector T cells. This indicates that senescence signalling may govern the unique characteristics of effector T cells. In this article, we address the functional and migratory properties of these T cells and mechanisms that are involved in their generation. Finally we assess the potential for manipulation of their activity and whether this may improve immune function during ageing.
Highlights
► CD45RA re-expressing T cells are pre-senescent memory T cells. ► Although non-proliferative, these cells exert potent effector function. ► CD45RA re-expressing T cells reside in skin, BM and spleen but not lymph nodes. ► Cell generation is cytokine driven and antigen independent. ► CD45RA re-expressing cell cycle block is maintained by inhibitory signalling.
