title: Age-related differences in integrin expression in peripheral blood lymphocytes.
abstract: Alpha integrins play an important role in cell to cell and cell to extra-cellular matrix interactions required for an effective T-lymphocyte-mediated immune response, however little is known about age related differences in expression of alpha integrins on T-cells in humans. We here measured alpha-4 (alpha4) integrin (CD49d) expression on T-lymphocytes via peripheral blood sampling, comparing parameters between cohorts of young and old adults. No age-related differences were found for the absolute numbers of T-cells, although the percentage of CD4+ T-cells in older adults was significantly greater and the percentage of CD8+ T-cells lower than in younger cohorts. Percentage and absolute numbers of CD3+ T-cells co-expressing CD49d were significantly lower in older adults compared to younger cohorts, and the percentage of gated CD4+ and CD8+ cells that co-labelled positively for CD49d was also reduced in this group. There were no age-related differences in circulating levels of cytokines (Type I interferons) that are known to regulate cell surface integrin expression. Reduced expression of alpha integrins on T-cells may be an early indicator of the loss of homeostatic control that occurs with ageing, contributing to diminished effector T-cell responses during senescence.
authors.affiliation: Institute Food, Nutrition and Human Health, Massey University, Auckland, New Zealand. christine.crooks@adhb.govt.nz.
authors.forename: Christine V
authors.initials: CV
authors.lastname: Crooks
authors.forename: Martin L
authors.initials: ML
authors.lastname: Cross
authors.forename: Clare R
authors.initials: CR
authors.lastname: Wall