Abundance of Rare Immune Cell Type in Supercentenarians May Help Maintain Healthy Aging
Researchers studying immune cells in Japanese supercentenarians have found that normally rare, CD4 cytotoxic T lymphocytes become increasingly abundant with extreme age, and may help to stave off cancer. The post Abundance of Rare Immune Cell Type in Supercentenarians May Help Maintain Healthy Aging appeared first on GEN - Genetic Engineering and Biotechnology News .
Aging brings a heightened risk of diseases and a weakened immune system compared to younger individuals. This has posed a puzzle for researchers: why do some people live to extreme ages without major diseases? A study by Osaka University suggests that a rare type of immune cell called CD4 cytotoxic T lymphocytes, or CD4 CTLs, becomes more abundant as people age.
These cells can recognize and destroy dangerous cells. "Immune aging is not simply a process of decline," said associate professor Kosuke Hashimoto. "The selective expansion of certain T cells suggests that, even in extreme old age, the immune system may continue to adapt to age-related challenges." The researchers analyzed blood samples of 28 adults, aged 70–99 years, 100–109 years, and 110 years and older.
They discovered that the proportion of CD4 CTLs increased with age, reaching nearly one-fifth in supercentenarians. These cells were uncommon throughout most of life but expanded dramatically around the age of 100. In supercentenarians, CD4 CTLs comprised nearly one-fifth of all T cells in the blood, compared to about 4% in younger study participants.
The study found signs of immune remodeling in extreme old age, with CD4 CTLs remaining highly active and potentially helping the body cope with persistent threats that increase with age. While the study suggests CD4 CTL expansion begins around 100, one participant younger than 100 had the highest proportion of these cells. The researchers also discovered that CD4 CTLs clone themselves when the immune system is under attack, with the most prominent clone accounting for an average of 33.3% of CD4 CTLs in older adults.
The researchers matched the receptor sequences of each participant's top CD4 CTL clone to those in a public database and found nearly three dozen matches belonged to people with cancer, such as lung, breast, and liver cancers. This led the researchers to theorize that their CD4 CTL expansion may reflect early immune responses to cancer.
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