Medical Research Council - London Institute of Medical Sciences

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Constrained and Restrained

Constraining tissue macrophages (type of immune cell) in pores prevents them participating in inflammation

30 December 2018

Constrained and Restrained

Some macrophages [a type of immune cell] circulate in the blood like patrolling soldiers on the lookout for invaders. But others are more akin to stationed sentinels, residing long-term within tissues, inactive but ever-ready. Unlike their circulating counterparts, these tissue-dwelling cells are not easily rallied by inflammatory signals, remaining inactive until the fight (tissue damage) comes to their door. While, this inactivity has benefits, ensuring tissues don’t become unnecessarily inflamed, how it’s controlled was unclear. Now scientists have found that the spatial constraints of the tissue keep the cells in check. This electron microscope image (false coloured) shows a macrophage sequestered in an artificial pore, which reduces the cell’s ability to spread out – an intrinsic part of activation. The discovery not only explains why tissue-resident macrophages remain dormant, but may also inform the design of medical implants, which if given porous surfaces might reduce inflammatory reactions.

Written by Ruth Williams

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