Fig. 2

The main markers of immunosenescence. The main feature of immunosenescence is the degeneration of the thymus, which is accompanied by a decrease in IL-7 secretion. Senescence is accompanied by a decrease in telomere length and telomerase activity. Senescence T cells show reduced SA-β-galactosidase activity, cytotoxic activity, expression of functional molecules such as IFN-γ, scarce proliferation, and also arrested cell cycle, due to an increase of the related proteins, P16 and P21. During the remodeling of the immune system with age, changes in immune cell markers are mainly characterized by the loss of CD27 and CD28 expression and the increase in CD57 and KLRG-1 expression. During aging, glycolysis and ROS production are increased, while mitochondrial synthesis is decreased