Identification and characterization of specific receptors for monocyte-derived neutrophil chemotactic factor (MDNCF) on human neutrophils

Localization of chemotactic activity and 64 kD protein phosphorylation for human polymorphonuclear leukocytes in N-terminus of the chemotactic protein LUCT/IL-8

A synthetic peptide, AVLPRSAKEL (LU10), the N-terminal amino acid sequence of chemotactic protein (LUCT/IL-8), showed chemotactic activity to polymorphonuclear leukocytes (PMN) with an ED50 of 5 nM for comparable to that of LUCT. Native LUCT and LU10 specifically induced the phosphorylation of 64 kD protein of PMN, and serine residue in the 64 kD protein was major phosphorylated amino acid. Furthermore, native LUCT enhanced the release of myeloperoxidase and beta-glucuronidase from PMN in the presence of cytochalasin B and FMLP, but LU10 did not. These results strongly suggest that the active site for both chemotactic stimulation and 64 kD protein phosphorylation is localized on the sequence of N-terminal 10 amino acids of LUCT.

Neutrophil activating factor (NAF) induces polymorphonuclear leukocyte adherence to endothelial cells and to subendothelial matrix proteins

Neutrophil activating factor is a polypeptide cytokine released from stimulated mononuclear phagocytes and endothelial cells. We found that neutrophil activating factor induced time- and concentration-dependent binding of human polymorphonuclear leukocytes to endothelial monolayers and subendothelial matrix proteins, via a mechanism that involves altered expression of the leukocyte CD11/CD18 glycoproteins. Thus, neutrophil activating factor is a third mediator, in addition to platelet-activating factor and endothelial leukocyte adhesion molecule 1, that is synthesized by activated endothelium and that can induce polymorphonuclear leukocyte adhesion to endothelial cells. Because NAF is released into the pericellular fluid, it may also stimulate binding of the leukocytes to exposed subendothelial structures at sites of vascular injury.