Osaka University scientists find rare immune cells elevated in centenarians
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Researchers at Osaka University found that people aged 90–100 and older have unusually high activity of rare immune cells capable of killing damaged and cancerous cells. The study, published in Cell Press, examined blood samples from 28 Japanese individuals. The proportion of cytotoxic CD4 T cells rose from about 4% in people aged 70–90 to 17.6% in those over 100.
Key Facts
- The median proportion of CD4 CTL was about 4% in participants aged 70–90, 9.6% in centenarians, and 17.6% in those over 100.
- About one-third of CD4 CTL in participants were clones derived from a single original cell, and in one centenarian nearly half shared a common ancestor.
- The study was published in the journal Cell Press and included blood samples from 28 Japanese individuals.
- Researchers cautioned that the study does not prove a direct link between elevated CD4 CTL and exceptional longevity and cannot be automatically generalized to all populations.
Immune Cell Findings
Scientists from Osaka University in Japan discovered unusually high activity of a rare type of immune cell in people aged 90–100 and older. The cells, cytotoxic CD4 T cells (CD4 CTL), normally occur rarely and belong to T-helper cells but can directly kill infected, damaged, and potentially cancerous cells. The median proportion of CD4 CTL was about 4% in participants aged 70–90, rose to 9.6% among centenarians, and reached 17.6% in those over 100. The cells remained active and showed no signs of exhaustion.
Clonal Expansion
Analysis showed that the increase in CD4 CTL numbers was linked to active proliferation. On average, about one-third of CD4 CTL in participants were clones derived from a single original cell. In one centenarian, nearly half of these cells had a common ancestor. Researchers explained that this process may be part of the immune system's adaptation to aging, helping to recognize and eliminate damaged, senescent, and potentially cancerous cells.
Study Limitations
The researchers emphasized that the work does not yet prove a direct link between elevated CD4 CTL and exceptional longevity. The study included only 28 people from Japan, so its results cannot be automatically extended to the entire population. Nevertheless, the finding shows that immune system aging does not necessarily mean weakening; in some people, immunity can restructure and strengthen specific defense mechanisms.
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Osaka University scientists find rare immune cells elevated in centenarians
