title: Losing TREC with age.
abstract: In this issue of Immunity, den Braber et al. (2012) highlight differences in naive T cell lifespan between mice and humans. Their data suggest that mechanisms of naive T cell maintenance may differ between mice and men.
authors.affiliation: Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Shirley L
authors.initials: SL
authors.lastname: Zhang
authors.forename: Avinash
authors.initials: A
authors.lastname: Bhandoola