In a new study published in the Journal of Neuroinflammation, scientists from the Becker group at the Center for Regenerative Therapies Dresden (CRTD) at TUD Dresden University of Technology and the University of Edinburgh have discovered exactly how zebrafish deploy a specific type of immune cell to gently restore harmony and pave the way for nerve regeneration.

The immune system is a complex orchestra with many cell types, each having its own part to play. When an injury occurs, the very first cells to arrive at the site are neutrophils. Historically, researchers thought of these cells as a simple cleanup crew that clears away debris from the injury site. However, the Becker team discovered that a specific subgroup of these neutrophils has a crucial job: Like a conductor in an orchestra, these cells signal the rest of the immune system to dial down their response and return to a harmonious rhythm of regeneration. Their secret? A signaling molecule called IL-4.