Endothelial Cell Line EAhy926 Research Articles

Anti-endothelial cell antibodies to the endothelial hybridoma cell line (EAhy926) in systemic lupus erythematosus patients with antiphospholipid antibodies.

The endothelial hybridoma (EAhy926) cell line was employed to clarify whether antiphospholipid antibodies (aPA) [lupus anticoagulant (LA), antiprothrombin antibody (aPT) and/or anticardiolipin antibody (aCL)] and anti-endothelial cell antibodies (AECA) are identical, and establish whether beta2-glycoprotein I (beta2-GPI) is needed for reactivity of aPA to endothelial cells. Ig-G AECA was positive in 9/30 SLE patients with aPA (30.0%) and 10/22 SLE patients negative for aPA (45.5%). Ig-M AECA was positive in one SLE patient with aPA and one SLE patient without aPA. AECA-positivity was not significantly different among unfixed, TNF-stimulated and fixed EAhy926. The influence of beta2-GPI on the reactivity of serum to EAhy926 was minimal, and absorption experiments of serum with cardiolipin-liposome/beta2-GPI or phosphatidylserine-liposome/prothrombin gave little evidence of cross-reactivity of aPA and AECA. The results of our study suggest that aPA and AECA may have partially cross-reacted, but were different antibodies. However, further study is needed to clarify the clinico-pathological significance of AECA.

Regulation of ICAM-1 by dexamethasone in a human vascular endothelial cell line EAhy926.

Regulation by dexamethasone of intercellular adhesion molecule-1 (ICAM-1) in cultured monolayers of the human umbilical vein endothelial cell line EAhy926 was investigated. Tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) in combination or lipopolysaccharide (LPS) alone gave time- and dose-dependent increases in ICAM-1. Sustained expression of ICAM-1 was observed after short exposure (30 min) to TNF-alpha + IFN-gamma, but not to LPS. LPS-induced ICAM-1 expression was not inhibited by interleukin-1 (IL-1) receptor antagonist (0.01-100 micrograms/ml). Dexamethasone (1,000 nM) did not inhibit TNF-alpha + IFN-gamma-induced ICAM-1 expression or mRNA induction. In contrast, dexamethasone dose dependently (0.1-1,000 nM) inhibited LPS-induced ICAM-1 expression; however, its effect on mRNA was not established, because ICAM-1 mRNA induced by LPS was not detected at the time points investigated in this study (3 and 20 h). Adhesion of unstimulated human neutrophils to EAhy926 monolayers activated with TNF-alpha + IFN-gamma or LPS was increased in the presence of dexamethasone at low doses, whereas neutrophil adhesion to LPS- but not cytokine-stimulated endothelial cells was significantly reduced (P < 0.05) in the presence of a high dose of dexamethasone (1,000 nM). In conclusion, dexamethasone was demonstrated to regulate the expression and function of ICAM-1 in a stimulus-dependent manner.

A monoclonal antibody to the human leukocyte adhesion molecule intercellular adhesion molecule-2. Cellular distribution and molecular characterization of the antigen.

The DNA of the human leukocyte adhesion molecule intercellular adhesion molecule-2 (ICAM-2) was synthesized by the polymerase chain reaction, and a protein A-ICAM-2 fusion protein was expressed in Escherichia coli. The fusion protein was used as immunogen to obtain mAb to ICAM-2. The 6D5 antibody was selected by its reactivity in immunofluorescence with the endothelial cell line Eahy926. The antibody precipitated a 55,000 m.w. glycoprotein from radioactivity surface labeled cells and also reacted in Western blotting. As measured by immunofluorescence flow cytometry, the antibody reacted with lymphoblastoid B cells of normal origin, some Burkitt lymphoma cell lines, vascular endothelial cells, the endothelial cell line Eahy926, 4 and a subpopulation of Con A-stimulated blood mononuclear cells. The two Ig-like domains of ICAM-2 were separately expressed in E. coli, and the antibody was shown to react with the NH2-terminal domain. The antibody inhibited the CD11/CD18-dependent binding of HL-60 promyelocytic leukemia cells to transfected COS-1 cells.