LFA-1 (CD11a/CD18) and Mac-1 (CD11b/CD18) distinctly regulate neutrophil extravasation through hotspots I and II

Abstract

Immune response: White blood cells follow the leader In response to infection or tissue damage, white blood cells known as leukocytes exit blood vessels at specific sites, “hotspots.” Many leukocytes follow each other out through the same hotspot. As part of the body’s initial response to infection or tissue damage, leukocytes are carried to infected or damaged tissues by blood vessels. To fight infection, they must exit the vessels, but how they exited was poorly understood. Young-Min Hyun at the Yonsei University College of Medicine in Seoul, South Korea and co-workers used advanced imaging techniques to visualize leukocyte delivery. They found that many leukocytes use a single hotspot to enter the blood vessel wall, travel through the wall’s interior, and then exit the wall at another hotspot. Using hotspots is thought to minimize the number of perforations in the vessel wall, maintaining vessel integrity. These results illuminate a key aspect of how efficiently the body fights infection from the viewpoint of leukocyte migration.