Proteoglycans on endothelial cells present adhesion-inducing cytokines to leukocytes.

Leukocyte recruitment from the blood circulation into tissue is essential for effective immune responses, and is, consequently, carefully regulated. In this article Yoshiya Tanaka and co-workers describe a model in which proteoglycans on the luminal surface of endothelium capture pro-adhesive cytokines. These cytokines provide the adhesion-inducing signal to particular leukocyte subsets which initiates their transmigration.