Tumor necrosis factor-alpha induces leukocyte recruitment by different mechanisms in vivo and in vitro.
It is well established that E-selectin is the endothelial adhesion molecule that is primarily responsible for mediating leukocyte rolling on TNF-alpha-stimulated cultured endothelial cells. Despite this, few studies in in vivo inflammatory models have observed reduced leukocyte accumulation using mAbs against E-selectin. The objective of this study was to compare the function of E-selectin on endothelial cells in vitro with its role in TNF-alpha-induced leukocyte recruitment in vivo using EL246, a mAb that blocks the function of E-selectin on activated feline endothelial cells. In vitro experiments using feline endothelial cells showed that EL246 functionally inhibits E-selectin-dependent leukocyte recruitment induced by TNF-alpha, without affecting the function of other rolling mechanisms. Intravital microscopy of single 25- to 40-microm venules in the feline mesentery was then used to examine leukocyte rolling and adhesion in response to superfusion with TNF-alpha. TNF-alpha treatment significantly increased the number of both rolling and adherent leukocytes and significantly decreased leukocyte rolling velocity. Treatment with EL246 (1 mg/kg), either i.v. at the start of the TNF-alpha protocol or directly into the superior mesenteric artery after 3 h of TNF-alpha treatment, had no effect on leukocyte rolling, adhesion, or rolling velocity. However, treatment with the selectin-binding carbohydrate, fucoidan, reduced leukocyte rolling to below baseline levels. These results suggest that in contrast to its prominent role on cultured endothelial cells, E-selectin does not contribute to leukocyte recruitment in TNF-alpha-stimulated feline mesenteric venules in vivo.
Hickey
M J
MJ
Immunology Research Group, University of Calgary, Alberta, Canada.
Reinhardt
P H
PH
Ostrovsky
L
L
Jones
W M
WM
Jutila
M A
MA
Payne
D
D
Elliott
J
J
Kubes
P
P
D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry; D002415:Cats; D002478:Cells, Cultured; D002634:Chemotaxis, Leukocyte / Q000187:drug effects / Q000276:immunology*; D019040:E-Selectin / Q000096:biosynthesis / Q000276:immunology / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D007269:Injections, Intra-Arterial; D019041:L-Selectin / Q000276:immunology / Q000494:pharmacology; D008643:Mesentery / Q000098:blood supply; D009504:Neutrophils / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000008:administration & dosage* / Q000494:pharmacology*; D014684:Venae Cavae; D014699:Venules / Q000187:drug effects
D000911:Antibodies, Monoclonal; D019040:E-Selectin; D014409:Tumor Necrosis Factor-alpha; D019041:L-Selectin