In vivo and in vitro functional examination of a conserved epitope of L- and E-selectin crucial for leukocyte-endothelial cell interactions.
Selectins constitute a three-member gene family of carbohydrate-binding adhesion proteins found on the surface of leukocytes and endothelial cells that is central to inflammation-associated leukocyte recruitment and lymphocyte recirculation. E- and P-selectin are inducible and expressed on the surface of endothelial cells under inflammatory conditions, whereas L-selectin is constitutively expressed on most circulating leukocytes. Previously, we have characterized a unique mAb (EL-246) that recognizes a common epitope on both E- and L-selectin, which is presented or determined by their short consensus repeat domains. This report defines the functional properties of EL-246 and its cognate epitope. In a novel in vitro physiologic shear system, we show that neutrophil rolling on activated HUVECs and on E-selectin cDNA transfectants is blocked 45 to 120 s after infusion of EL-246. The examination of the binding of neutrophils to E-selectin cDNA transfectants reveals that their adhesion is blocked by EL-246 treatment of either cell type. A unique Ab transfer mechanism is demonstrated in which El-246 is delivered unidirectionally from L- to E-selectin to surpass the adhesion blocked by mAbs that recognize either L- or E-selectin alone. By using flow cytometry and in vivo homing techniques, we show that pretreating bovine lymphocytes with EL-246 blocks their ability to home to mouse peripheral lymph nodes by > 65%. Cumulatively, these results suggest that EL-246 is a uniquely potent pharmacologic inhibitor of leukocyte-endothelial cell interactions that are mediated by either E- or L-selectin.
Bargatze
R F
RF
Veterinary Molecular Biology Laboratory, Montana State University, Bozeman 59717.
Kurk
S
S
Watts
G
G
Kishimoto
T K
TK
Speer
C A
CA
Jutila
M A
MA
D000818:Animals; D000911:Antibodies, Monoclonal; D002417:Cattle; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000276:immunology* / Q000502:physiology; D002450:Cell Communication; D002465:Cell Movement; D018076:DNA, Complementary / Q000235:genetics; D019040:E-Selectin; D004727:Endothelium / Q000276:immunology / Q000502:physiology; D000939:Epitopes / Q000235:genetics; D006801:Humans; D066298:In Vitro Techniques; D019041:L-Selectin; D007962:Leukocytes / Q000276:immunology / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009504:Neutrophils / Q000276:immunology / Q000502:physiology; D014162:Transfection
D000911:Antibodies, Monoclonal; D015815:Cell Adhesion Molecules; D018076:DNA, Complementary; D019040:E-Selectin; D000939:Epitopes; D019041:L-Selectin