Molecular characterization and functional analysis of the leukocyte surface protein CD31.

Abstract

The CD31 Ag is a surface glycoprotein of 130 kDa with a broad cellular distribution. We show that among peripheral human blood cells, it is expressed on monocytes, granulocytes, platelets, and a subpopulation of lymphocytes. Activation of granulocytes leads to down-regulation of CD31 molecule expression. Sequence analysis and quantitative measurements of the relatedness of the CD31 molecule to other known proteins demonstrate that it consists of six Ig constant domains and that each domain bears substantial similarity to Fc gamma R domains. We find, however, that the CD31 molecule does not bind Ig Fc domains. On human monocytes we demonstrate that CD31 mAb recognizing certain epitopes of the CD31 molecule induce the generation of reactive oxygen metabolites. No such effect was seen with human granulocytes. By using two CD31 mAb, termed 1B5 and 7E4, we analyzed the requirements for activation of the monocyte respiratory burst via CD31 Ag in more detail. We show that signal transduction occurs via formation of a CD31 Ag-mAb-Fc gamma R complex involving either Fc gamma RI (CD64) or Fc gamma RII (CDw32) molecules.

CD31 as a probable responding and gate-keeping protein of the blood-brain barrier and the risk of Alzheimer’s disease

“…CD31 is predominantly expressed in endothelial cells, 14 platelets, 9,15 different subpopulations of leukocytes (neutrophils, monocytes, eosinophils, and several lymphocyte subsets), 16,17 hematopoietic progenitor cells, 18 and megakaryocytes. 19 In endothelia, CD31 is located just adjacent to tight junction complexes, which have been reported to be regulated by the expression of CD44 and comprise the vascular permeability barrier 20–23 (Figure 1).…”

“…9 The extracellular domains play an important role in the adhesion cascade, where the first two structural domains (2 amino-terminal immunoglobulin homology) determine hemophilic binding 10,11 and are involved in leukocyte-endothelial interaction, 12 leukocyte transendothelial migration 13 and stabilization of endothelial cell-cell junctions. 11 CD31 is predominantly expressed in endothelial cells, 14 platelets, 9,15 different subpopulations of leukocytes (neutrophils, monocytes, eosinophils, and several lymphocyte subsets), 16,17 hematopoietic progenitor cells, 18 and megakaryocytes. 19 In endothelia, CD31 is located just adjacent to tight junction complexes, which have been reported to be regulated by the expression of CD44 and comprise the vascular permeability barrier [20][21][22][23] (Figure 1).…”

Autoimmune Disease-Related Hub Genes are Potential Biomarkers and Associated with Immune Microenvironment in Endometriosis

“…41 Due to its involvement in numerous mechanisms, including leukocyte movement through intracellular junctions, cell death, angiogenesis, etc, PECAM-1 plays a variety of diverse and broad roles in inflammation. 42 Inhibiting PECAM1 in animal models of arthritis can stop the advancement of inflammation. Additionally, it has been discovered that through stimulating the NF-κB signaling pathway, PECAM1 and CXCR 4 can interact to increase the inflammatory response in pulpitis samples.…”