V?2+ and ?/? T cells show divergent trajectories during human aging

Abstract

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