Induction of CD56 and TCR-independent activation of T cells with aging.

Journal Article

Degeneration of the thymus and severe contraction of the T cell repertoire with aging suggest that immune homeostasis in old age could be mediated by distinct effectors. Therefore, receptors expressed on T cells as they undergo senescence in vitro, as well as those displayed by circulating T cells during normal chronologic aging, were examined. Monitoring of T cells driven to senescence showed de novo induction of CD56, the prototypic receptor of NK cells. Analysis of fresh T cells in peripheral blood showed an age-dependent induction of CD56. These unusual T cells expressed high levels of Bcl2, p16, and p53, and had limited, or completely lost, ability to undergo cell division, properties consistent with senescence. CD56 cross-linking without TCR ligation on CD56(+) T cells resulted in extensive protein phosphorylation, NF-kappaB activation, and Bax down-regulation. CD56 cross-linking was also sufficient to drive production of various humoral factors. These data suggest that the immunologic environment in old age is functionally distinct, rather than being a dysfunctional version of that seen at a young age. CD56(+) T cells are unique effectors capable of mediating TCR-independent immune cascades that could be harnessed to enhance protective immunity in the elderly.

Full Text

Duke Authors

Cited Authors

  • Lemster, BH; Michel, JJ; Montag, DT; Paat, JJ; Studenski, SA; Newman, AB; Vallejo, AN

Published Date

  • February 1, 2008

Published In

Volume / Issue

  • 180 / 3

Start / End Page

  • 1979 - 1990

PubMed ID

  • 18209097

International Standard Serial Number (ISSN)

  • 0022-1767

Language

  • eng

Conference Location

  • United States