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Atom bomb tests used to age the immune system

The pulse of environmental carbon-14 released by atom bomb tests in the early years of the Cold War has allowed researchers to understand how humans can still mount an immune response to diverse pathogens well into their 50's and 60's, according to a study led by Jonas Frisén at the Karolinska Institute in Sweden, publishing on October 29 in the open-access journal PLOS Biology.  T cells, which are produced by the thymus and represent one of the major arms of our immune defences, have unique and highly variable cell surface receptors that allow them to detect specific molecular patterns presented by pathogens or cancerous cells. Thus, the diversity of a person's T cell repertoire determines the diversity of pathogens and cancer cells that their immune system can target. But as we age, new T cells are no longer produced by the thymus; instead the T cell pool is maintained by existing T cells replicating clonally.  Read more....



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