Proteinase 3 contributes to transendothelial migration of NB1-positive neutrophils

J Immunol. 2012 Mar 1;188(5):2419-26. doi: 10.4049/jimmunol.1102540. Epub 2012 Jan 20.


Neutrophil transmigration requires the localization of neutrophils to endothelial cell junctions, in which receptor-ligand interactions and the action of serine proteases promote leukocyte diapedesis. NB1 (CD177) is a neutrophil-expressed surface molecule that has been reported to bind proteinase 3 (PR3), a serine protease released from activated neutrophils. PR3 has demonstrated proteolytic activity on a number of substrates, including extracellular matrix proteins, although its role in neutrophil transmigration is unknown. Recently, NB1 has been shown to be a heterophilic binding partner for the endothelial cell junctional protein, PECAM-1. Disrupting the interaction between NB1 and PECAM-1 significantly inhibits neutrophil transendothelial cell migration on endothelial cell monolayers. Because NB1 interacts with endothelial cell PECAM-1 at cell junctions where transmigration occurs, we considered that NB1-PR3 interactions may play a role in aiding neutrophil diapedesis. Blocking Abs targeting the heterophilic binding domain of PECAM-1 significantly inhibited transmigration of NB1-positive neutrophils through IL-1β-stimulated endothelial cell monolayers. PR3 expression and activity were significantly increased on NB1-positive neutrophils following transmigration, whereas neutrophils lacking NB1 demonstrated no increase in PR3. Finally, using selective serine protease inhibitors, we determined that PR3 activity facilitated transmigration of NB1-positive neutrophils under both static and flow conditions. These data demonstrate that PR3 contributes in the selective recruitment of the NB1-positive neutrophil population.

MeSH terms

  • Enzyme Activation / genetics
  • Enzyme Activation / immunology
  • GPI-Linked Proteins / biosynthesis
  • GPI-Linked Proteins / genetics
  • GPI-Linked Proteins / physiology
  • Gene Expression Regulation / immunology
  • Human Umbilical Vein Endothelial Cells
  • Humans
  • Isoantigens / biosynthesis*
  • Isoantigens / genetics
  • Isoantigens / physiology
  • Myeloblastin / biosynthesis
  • Myeloblastin / genetics
  • Myeloblastin / physiology*
  • Neutrophils / cytology
  • Neutrophils / enzymology*
  • Neutrophils / immunology*
  • Receptors, Cell Surface / biosynthesis*
  • Receptors, Cell Surface / genetics
  • Receptors, Cell Surface / physiology
  • Transendothelial and Transepithelial Migration / immunology*


  • CD177 protein, human
  • GPI-Linked Proteins
  • Isoantigens
  • Receptors, Cell Surface
  • Myeloblastin