Format

Send to

Choose Destination
Vaccine. 2000 Feb 25;18(16):1661-5.

Costimulatory mechanisms in the elderly.

Author information

1
Department of Pathology and Laboratory Medicine, UCLA School of Medicine, 10833 Le Conte Avenue, Los Angeles, CA 90095-1732, USA. reffros@mednet.ucla.edu

Abstract

Aging is associated with the progressive increase of T cells that lack expression of the CD28 costimulatory molecule. Because CD28/B7 signal transduction is required for proliferation, T cells lacking CD28 gene expression are incapable of clonal expansion. To determine whether CD28- T cells are a separate lineage or, alternatively, are the progeny of formerly CD28+ T cells, we performed cell culture longitudinal analysis on the same population of T cells over time. Repeated antigen-induced T cell division ultimately leads to irreversible cell cycle arrest, shortened telomeres, loss of telomerase inducibility, and total absence of expression of CD28. This in vitro model has elucidated a novel facet of T cell biology that may explain the increased incidence of infection and cancer in the elderly.

PMID:
10689145
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center