Uncovering an adaptive immune hallmark of extreme longevity.

In a recent paper, Hashimoto et al. used single-cell profiling to reveal that supercentenarians harbor expanded, nonexhausted CD4+ cytotoxic T lymphocytes. These cells retain potent cytotoxicity and functional plasticity, suggesting an adaptive immune restructuring to manage persistent MHC class II-restricted antigens, potentially contributing to their exceptional healthy aging.