How Brain’s ‘Immune Cells’ Can Fight Meningitis, Alzheimer’s—or Backfire

When the cells switch to their aggressive form, they can kill neutrons and cause further damage to our brains

Microglia cells (red) play an important role in the pathogenesis of Alzheimer's disease. Microglia are specialised macrophages that restrain the accumulation of amyloid (orange plaques). Juan Gaertner/Shutterstock

We know that the body’s immune system is important for keeping everything in check and protecting us. But a lot of us don’t realize that the brain also has an immune system.

Microglia, which are the brain’s immune system cells, are involved in everything—from brain development to protecting against diseases such as meningitis and Alzheimer’s. But for all the good these cells do for us, under the wrong conditions they can also cause us harm.