# Naive vs. memory T cells

Naive T cells are antigen-inexperienced lymphocytes that continuously recirculate through secondary lymphoid organs awaiting their cognate antigen; they are generated in the thymus and depend on tonic TCR and IL-7 signals for peripheral survival. Upon antigen encounter and co-stimulation, they clonally expand and differentiate into effector cells and, subsequently, long-lived memory T cells (central, effector, and tissue-resident subtypes) that enable faster, stronger recall responses. With age, the naive compartment contracts due to thymic involution and homeostatic proliferation-driven phenotypic conversion, while the memory compartment expands — particularly oligoclonal CD8+ populations driven by persistent viral antigens such as CMV. This shift narrows the T-cell receptor repertoire and limits the capacity to respond to novel pathogens or vaccines.

## Sources

- Goronzy JJ, Weyand CM. (2017). Successful and Maladaptive T Cell Aging. Immunity. https://doi.org/10.1016/j.immuni.2017.03.010
- Goronzy JJ, Weyand CM. (2019). Mechanisms Underlying T Cell Ageing. Nature Reviews Immunology. https://doi.org/10.1038/s41577-019-0180-1

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_Canonical: https://longevity-china.com/en/glossary/naive-memory-t-cells · Part of Longevity Cities · Updated 2026-05-01_