The TCF1-centered stemness network as the foundation of T cell longevity

Adaptive immunity depends on the extraordinary longevity of the T-cell compartment, yet the mechanisms that sustain immune competence across decades remain incompletely understood. Traditional models emphasize homeostatic proliferation and cellular replacement as the basis of T-cell maintenance. Here, we propose an alternative framework in which long-term immune resilience depends primarily on preservation of stemness through cellular quiescence. Evidence from human aging studies indicates that naïve and stem-like memory T cells achieve exceptional longevity by limiting rather than maximizing turnover. Aging is therefore best understood as a progressive loss of stem-like cellular states, characterized by erosion of a TCF1-centered regulatory network that integrates FOXO1-dependent quiescence, BACH2-mediated restraint of differentiation, Wnt-dependent stemness reprogramming, and lysosomal-metabolic fitness. Exemplified by this model, intrinsic differences in the ability to maintain this network may account for the unequal aging of CD4 and CD8 T cells. Preserving T-cell stemness may represent a central goal of immune rejuvenation strategies.