CELLS that refuse to die could be the undoing of the immune system as we
age.
Immune T cells that carry proteins called CD4 and CD28 on their surface play
a crucial role in rallying immunity to an invading pathogen. But during normal
ageing, and in certain inflammatory diseases such as rheumatoid arthritis, half
the circulating T cells that carry CD4 can lose their CD28. These cells seem to
be less effective at boosting immunity and also develop dangerous tendencies,
such as killing other human cells.
It hasn’t been clear why these cells end up playing such a major role. Now…
