title: The effect of aging and caloric restriction on murine CD8+ T cell chemokine receptor gene expression.
abstract: BACKGROUND
  The mechanism explaining the increased disease susceptibility in aging is not well understood. CD8+ T cells are crucial in anti-viral and anti-tumor responses. Although the chemokine system plays a critical role in CD8+ T cell function, very little is known about the relationship between aging and the T cell chemokine system.
  
  
  RESULTS
  In this study we have examined the effect of aging on murine CD8+ T cell chemokine receptor gene expression. Freshly isolated splenic CD8+ T cells from old C57BL/6 mice were found to have higher CCR1, CCR2, CCR4, CCR5 and CXCR5, and lower CCR7 gene expression compared to their younger cohort. Anti-CD3/anti-CD28 stimulation elicited a similar robust chemokine receptor response from young and old CD8+ T cells. Western blot analyses confirmed elevated protein level of CCR4 and CCR5 in aged CD8+ T cells. Increases in T cell CCR1 and CCR5 expression also correlate to increased in vitro chemotaxis response to macrophage-inflammatory protein-1 alpha(MIP-1alpha). Finally, caloric restriction selectively prevents the loss of CD8+ T cell CCR7 gene expression in aging to the level that is seen in young CD8+ T cells.
  
  
  CONCLUSIONS
  These findings are consistent with the notion that aging exists in a state of low grade pro-inflammatory environment. In addition, our results provide a potential mechanism for the reported aging-associated impaired T cell lymphoid homing and allograft response, and reduced survival in sepsis.
authors.affiliation: Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA. ryung@umich.edu
authors.forename: Raymond
authors.initials: R
authors.lastname: Yung
authors.forename: RuRan
authors.initials: R
authors.lastname: Mo
authors.forename: Annabelle
authors.initials: A
authors.lastname: Grolleau-Julius
authors.forename: Mark
authors.initials: M
authors.lastname: Hoeltzel