Neutrophils secrete MIP-1β after adhesion to laminin contained in basement membrane of blood vessels

We have recently demonstrated that granulocyte colony-stimulating factor (G-CSF) stimulated the production of epithelial-cell-derived-neutrophil attractant-78 (ENA-78) by neutrophils and that ENA-78 might promote the accumulation of neutrophils that had migrated from the intravascular space into inflammatory tissues. In this study, we examined whether other chemokines could be secreted by neutrophils that had accumulated after migrating from the intravascular space into the inflammatory tissues. We demonstrated that adhesion to laminin contained in the basement membrane and Matrigel, which is an artificial basement membrane model, induced macrophage inflammatory protein-1β (MIP-1β) in neutrophils and that MIP-1β secreted by neutrophils induced the chemotaxis of dendritic cells. These findings suggest that neutrophils transmigrating through the basement membrane are stimulated to secrete MIP-1β by the basement membrane, inducing the transmigration of dendritic cells from the intravascular space into inflammatory tissues. We propose that neutrophils intervene between innate immune response and specific immune response by secreting MIP-1β during the transmigration through the basement membrane.