BD Rudd, V Venturi, G Li, P Samadder, JM Ertelt, SS Way, MP Davenport, J Nikolich-Žugich. (2011). " Nonrandom attrition of the naive CD8+ T-cell pool with aging governed by T-cell receptor:pMHC interactions. " Proc Natl Acad Sci U S A. 108, 13694-9. PMID: 21813761 DOI: 10.1073/pnas.1107594108
Immunity against new infections declines in the last quartile of life, as do numbers of naive T cells. Peripheral maintenance of naive T cells over the lifespan is necessary because their production drastically declines by puberty, a result of thymic involution. We report that this maintenance is not random in advanced aging. As numbers and diversity of naive CD8(+) T cells declined with aging, surviving cells underwent faster rates of homeostatic proliferation, were selected for high T-cell receptor:pMHC avidity, and preferentially acquired "memory-like" phenotype. These high-avidity precursors preferentially responded to infection and exhibited strong antimicrobial function. Thus, T-cell receptor avidity for self-pMHC provides a proofreading mechanism to maintain some of the fittest T cells in the otherwise crumbling naive repertoire, providing a degree of compensation for numerical and diversity defects in old T cells