Support cells of the inner ear behave like the immune system's macrophages
Rushing to the scene of an infection, our immune cells – including macrophages which 'digest' harmful pathogens – create a flurry of inflammation, sometimes experienced as redness or swelling. But sensitive organs like eyes and ears can’t afford to risk this collateral damage, and are often protected by a barrier of tissue that has immune privilege – a sort of ‘no go’ area for travelling immune cells. In theory this leaves some cells, like these in cochlea of the inner ear, more prone to infections. But the ears have a secret defence – here layers of supporting cells (dark blue top) also behave like macrophages, engulfing viral particles (green) – a process called phagocytosis. Indeed, depriving these local defenders of a macrophage-like protein, allows the virus to penetrate much deeper into the ear tissue (middle and right). Further investigation may reveal similar defences protecting other sensitive tissues.
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