Some immune cells stab their cellular partners during allergic reactions.
Mast cells, the immune system’s security patrols, can trigger allergic inflammation when they encounter unfamiliar proteins (SN: 9/5/07). For the first time, researchers have seen these overwhelmed cells attract and capture other key immune cells, then expel the inflammatory chemicals of their hostages in a process called nexocytosis. The discovery could help scientists understand the underlying causes of health conditions involving allergies or the immune system, such as asthma and dermatitis.
When mast cells sense proteins from outside the body, they trigger an inflammatory response by expelling granules, packets of chemicals that attract other immune cells — including neutrophils, a key type of white blood cell.SN: 23.9.24).
Curious about how mast cells and neutrophils interact, immunologist and biochemist Michael Mihlan and colleagues induced mast cells to react to a human blood protein. The team then observed the reactions in mouse and human cells through a microscope. Mast cells lured neutrophils toward them and then engulfed the specialized white blood cells, researchers reported Sept. 19. Cell. “This was a total surprise to us,” says Mihlan, from the University of Munster in Germany.
Even after the trapped neutrophils died, their proteins, DNA and other molecules remained inside their mast cell clamps. Mast cells can then use these scraps to sustain themselves. Or, they may perform nexocytosis by releasing neutrophil inflammatory chemicals along with granules when another allergic reaction is initiated.
In the future, Mihlan hopes to learn whether the mast cell’s capture strategy is a force for good in some cases, such as fighting foreign bacteria.
#allergic #reaction #immune #cells #attack
Image Source : www.sciencenews.org