Vδ2+and α/β T cells show divergent trajectories during human aging

Chronological aging and a variety of stressors are driving forces towards immunosenescence. While much attention was paid to the main T cell component, alpha/beta T cells, few studies concentrate on the impact of age gamma/delta T cells' characteristics. The latter are important players of adaptive immunity but also have features associated with innate immunity. V delta 2+ are the main component gamma/delta while V delta 1+ T cells expand upon Cytomegalovirus (CMV) infection and with age. The Vd2+ T cells are not influenced by persistent infections but do contribute to immunosurveillance against bacterial pathogens. Here, we focus on Vd2+ T cells and report that their composition and functionality is not altered in older adults. We have performed a side-by-side comparison of alpha/beta and V delta 2 cells by using two robust markers of T cell replicative history and cell differentiation (CD28 and CD27), and cytokine secretion (IFN-gamma and TNF-alpha). Significant differences in V delta 2 versus alpha/beta homeostasis, as well as phenotypic and functional changes emerged. However, the data strongly suggest a sustained functionality of the Vd2 population with age, independently of the challenge. This suggests differential trajectories towards immunosenescence in alpha/beta and V delta 2+ T cells, most likely explained by their intrinsic functions.