Effect of ageing and CMV infection on CD8 T cell subsets

摘要

Ageing is associated with changes in the immune system with substantial alterations in T-lymphocyte subsets. Clonal expansion of CMV-specific T cells is a common finding in the elderly and it has been postulated as a major driving force of immu-nosenescence. In this study, the effect of ageing on CD8 T cell subsets defined by the expression of CCR7 and CD45RA was analysed by using the HLA-A*0201/CMV pp65_(495-504)(NLVPMVATV) pentamer. The expression of NK associated receptors CD56, CD94 and CD85j on these subsets has also been studied. The results demonstrate an age-associated decrease in the percentage of naive cells and central memory CD8 T cells and an age-associated increase in the percentage of the CCR7~(null) effector-memory (EM) subset with a CD45RA~(dim) phenotype. This age association was observed both in the pentamer positive and pentamer-negative CD8 T cells. The NK receptor expression was also increased in the EM subsets in the elderly.