RESUMO
Changes in chemokine receptor expression are important in determining T cell migration and the subsequent immune response. To better understand the contribution of the chemokine system in immune senescence we determined the effect of aging on CD4(+) T cell chemokine receptor function using microarray, RNase protection assays, Western blot, and in vitro chemokine transmigration assays. Freshly isolated CD4(+) cells from aged (20-22 mo) mice were found to express a higher level of CCR1, 2, 4, 5, 6, and 8 and CXCR2-5, and a lower level of CCR7 and 9 than those from young (3-4 mo) animals. Caloric restriction partially or completely restored the aging effects on CCR1, 7, and 8 and CXCR2, 4, and 5. The aging-associated differences in chemokine receptor expression cannot be adequately explained by the age-associated shift in the naive/memory or Th1/Th2 profile. CD4(+) cells from aged animals have increased chemotactic response to stromal cell-derived factor-1 and macrophage-inflammatory protein-1alpha, suggesting that the observed chemokine receptor changes have important functional consequences. We propose that the aging-associated changes in T cell chemokine receptor expression may contribute to the different clinical outcome in T cell chemokine receptor-dependent diseases in the elderly.
