What the adaptive immune system is
The adaptive immune system is the specialised, learned arm of immunity — T cells and B cells that recognise specific pathogens, mount a targeted response, and remember them for faster future defence. It complements the fast, general-purpose innate immune system.
Why it matters for longevity
With age the adaptive immune system declines — a process called immunosenescence — while low-grade inflammation rises (inflammaging). The result is weaker responses to infection and vaccination, reduced clearance of senescent cells, and higher susceptibility to disease. Immune ageing is increasingly seen as a central longevity lever.
What the evidence shows
The biology of immunosenescence is well characterised, and its links to poorer outcomes in older adults are strong. Interventions to “rejuvenate” the ageing immune system are an active research area but remain largely experimental.
Bottom line
Immune ageing is a major, measurable component of biological ageing — well understood mechanistically, with therapies still emerging.