Reduced Naïve T Cell Numbers Correlate with Increased Low-Grade Systemic Inflammation During Ageing and Can be Modulated by Physical Activity

Abstract

Age-associated decline of immune system, termed immunosenescence, is characterized by low-grade systemic inflammation, known as inflammaging, together with T-cell functional dysregulation. Although affecting all individuals, differe nt environmental as well genetic factors impinge on the individual ́s susceptibility or resilience to immunosenescence. Physical ac tivity h s been shown to improve autonomy and functionality in older adults. However, if physical activity affects immunosenescence or inf lammagi g remains unknown. The purpose of this study was to analyze immunosenescence and inflammaging in elderly individuals by measuring peripheral naïve T cells and interleukin (IL) -6 from peripheral blood and evaluate the impact of physical activity on T cell d ysregu ation and inflammaging. Thirty (30) elderly volunteers (10 males and 20 females), and 7 young controls (2 males ad 7 females), were r ecruited for this study. A methodology questionnaire was used to evaluate different parameters such as physical activity, and peripheral naïve CD4 and CD8 T cells and serum IL-6 were measured by FACS and ELISA respectively. Our results shown that naïve T cells decline, and IL-6 levels increase as older people age. Interestingly, we observed strong negative correlation between naïve T cells numb ers and IL-6 levels in older adults, suggesting a direct link between reduced naïve T cell pool and increased inflammaging. Continuous physical activity during youth did not affect immunosenescence and inflammaging in elderly, but physical activity during elderly increas e naïv T cell numbers and reduce inflammaging in older subjects. Our results showed reduced number of naïve T cells and increased leve ls of IL-6 as elder people get older. Moreover, the strong negative correlation between these parameters suggest that naïve T cells c n have a direct suppressive activity over innate immune components. Furthermore, physical activity during elderly can reduce immunosenes cence and inflammaging in older subjects.