White blood cells move like many animals

How do white blood cells - 'warriors' of the immune system - reach the site of infection or injury? To do this, white blood cells must crawl rapidly along the blood vessels - clinging tightly to avoid the color swept away - at the same time searching for temporary "signposts" due to special molecules. make them know when and where they can cross the vascular barrier to reach the damaged tissue.

In a study published recently in the journal Immunity, Professor Ronen Alon and graduate student Ziv Shulman of the Department of Immunology at Weizmann Institute describe how white blood cells move along the length of the cells. endothelial cells are located inside the blood vessels. Most thought that immune cells shifted in the same way as measured worms, but Alon's new findings show that white blood cells move like multifocal animals.

Rather than moving forward by shrinking and stretching like a depth gauge, immune cells create very small legs with a length of just over a micron - clinging points, with many adherent molecules (called LFA- 1) associated with similar molecules on the surface of blood vessel walls. These pins attach and release in chains in seconds - allowing them to move quickly while still clinging to blood vessel walls.

Next, the scientists turned to the Institute's Electron Microscopes. The images obtained by scanning and transmitting electron microscopes, performed by Dr. Eugena Klein and Vera Shinder, show that before clinging to the walls of blood vessels, the legs of white blood cells 'pierce' through the surface. of endothelial cells. In fact, those legs - which were previously thought to appear only when cells leave the bloodstream - are used to crawl along blood vessels to show that they act as probes to sense the signal. exit.

Illustration of a white blood cell floating in blood vessels.(Photo: iStockphoto / Gary Caviness)

The researchers found that the force generated by the blood signaled the white blood cell's legs. Without the force of blood flow, these cells cannot recognize the exit signal or reach the damaged site. These results explain Alon's earlier findings that the force of blood flow is necessary to get rid of blood vessel walls of white blood cells. Current research shows that this force forces molecules to cling to a strong phase of activity. Scientists believe that these tiny legs have three functions: to grip, move, and sense signals from damaged tissues.

For future research, scientists plan to test whether it is possible to control an excessive immune response (such as autoimmune diseases) by interfering with the 'piercing' process. of the immune cell legs into the inner membrane. They also plan to study whether metastatic cancerous blood cells in the blood vessels use the same mechanism to get rid of blood vessels and into different tissues.

Ronen Alon's research was funded by the De Benedetti Cherasco Foundation in 1547. Professor Alon currently holds the position of president of Lina Jacos in stem cell and immune research.