Figure 1.

Schematic of neutrophil recruitment cascade: Flowing neutrophils roll on vascular endothelial cells through the interaction between PSGL-1 and selectins. Engagement of PSGL-1 with selectins induces the extension of LFA-1, which binds ICAM-1 or other ligands with an intermediate affinity and slows down rolling velocity. We call this process slow rolling. β1 Integrins are also involved in neutrophil rolling and slow rolling. When rolling neutrophils encounter chemokines, LFA-1 or Mac-1 will be fully activated and bind ICAM-1 or other ligands with a high affinity and stop rolling neutrophils. We call this process arrest. After arrest, neutrophils spread and crawl on endothelial cells, which is predominantly mediated by Mac-1. Neutrophils undergo trans-endothelial migration in an LFA-1/Mac-1-dependent manner to the tissue or site of injury. Created in BioRender.com (accessed on 12 June 2022).