Marked increase with age of type 1 cytokines within memory and effector/cytotoxic CD8+ T cells in humans: a contribution to understand the relationship between inflammation and immunosenescence

Exp Gerontol. 2003 Sep;38(9):981-7. doi: 10.1016/s0531-5565(03)00160-8.

Abstract

The ageing process is characterized by a progressive exhaustion of the naïve T cell reservoir that is accompanied by a compensatory expansion of effector/cytotoxic CD8+CD28- T cells. However, the origin and function of this subpopulation is not completely clarified. In this study, we examined the intracellular cytokine profile in purified CD8+ T cells obtained from 29 healthy subjects of different ages. Type 1 (IFN-gamma IL-2 and TNF-alpha) and type 2 (IL-4, IL-6 and IL-10) cytokines were determined in three CD8+ T subsets, i.e. CD95-CD28+ (naïve), CD95+CD28- (effector/cytotoxic), and CD95+CD28+ (memory). As a general trend, we observed, in aged subjects, an increase of type 1 and type 2 intracellular cytokines within the three CD8+ subsets. In particular, we showed that type 1 cytokine-positive cells significantly increased, with age, among all the CD8+ subsets, while a marked increase of type 2 producing cells was observed only in memory CD8+ T cells. These profound changes are compatible with inflame-aging, an hypothesis which suggest that immunosenescence is mainly driven by a chronic antigenic load which not only induces an enormous expansion of CD28- T cells, but also increases their functional activity, exemplified by an high frequency of cells positive for pro-inflammatory cytokines.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Aging / immunology*
  • Analysis of Variance
  • CD8-Positive T-Lymphocytes / immunology*
  • Cytokines / blood*
  • Flow Cytometry
  • Humans
  • Immunologic Memory
  • Immunophenotyping
  • Inflammation / immunology*
  • Lymphocyte Activation / immunology
  • Middle Aged
  • T-Lymphocyte Subsets / immunology*
  • T-Lymphocytes, Cytotoxic / immunology

Substances

  • Cytokines