Cross-linking of GPI-80, a possible regulatory molecule of cell adhesion, induces up-regulation of CD11b/CD18 expression on neutrophil surfaces and shedding of L-selectin

Previously, we described a novel glycosylphosphatidyl inositol (GPI)-anchored glycoprotein (designated GPI-80) on human neutrophils and monocytes that may regulate β2 integrin-dependent neutrophil adherence and migration. However, the mechanism regulating β2 integrin remains to be clarified. To study this, we examined changes in β2 integrin expression and function caused by cross-linking GPI-80. GPI-80 cross-linking induced up-regulation of CD11b/CD18 (Mac-1) expression on neutrophil surfaces and shedding of L-selectin, which depends on tyrosine phosphorylation and cytoskeleton remodeling. Furthermore, the cross-linking enhanced fMLP-induced human neutrophil adherence. These results suggest that GPI-80 may be a regulator of β2 integrin in neutrophils.