Identification of a human endothelial cell activation antigen that is co-expressed by germinal follicle centre B lymphocytes.
Endothelial cell activation antigens may play important roles in immune responses and in inflammation. This report describes the identification and characterization of a monoclonal antibody, named EAA-B, which reacts specifically with human umbilical vein endothelial (HUVE) cells pre-treated with tumour necrosis factor-alpha (TNF-alpha) but not with untreated cells. The expression of the EAA-B antigen on HUVE cells could also be induced by interleukin-1 (IL-1), bacterial lipopolysaccharide (LPS), and phorbol esters but not by interferon-gamma (IFN-gamma). By contrast, EAA-B antigen expression on neonatal foreskin and rheumatoid synovial fibroblasts, whether pre-treated with TNF-alpha or not, was not detectable. Peripheral blood leucocytes and the leukaemic cell lines U937, HL-60, Raji and Molt 4 showed no detectable expression of the EAA-B antigen. Kinetic studies demonstrated that the EAA-B antigen was rapidly expressed, peaked at 6 hr and declined to basal level by 24 hr. Western blotting revealed that monoclonal antibody EAA-B recognized a polypeptide of approximately 80,000-90,000 MW. EAA-B partially blocked the augmented adhesion of HL-60 cells to TNF-treated HUVE cells. However, it failed to inhibit the enhanced binding of peripheral blood leucocytes, U937, Raji and Molt 4 Cells to TNF-treated HUVE cells. In situ, the EAA-B antigen was detected on some vascular endothelium in tonsils, lymph nodes, psoriatic skin and rheumatoid synovium but not in normal non-lymphoid tissues. Interestingly EAA-B antigen is also expressed by B lymphocytes in germinal follicle centres (GFC) of lymphoid tissues. The co-expression of this endothelial activation antigen by GFC B lymphocytes may have significant implications for immune responses and in B-lymphocyte differentiation.
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Sutton Rheumatism Research Laboratory, Sydney University Department of Rheumatology, Royal North Shore Hospital, Australia.
Magoulas
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Nicholson
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Schrieber
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D000911:Antibodies, Monoclonal; D000954:Antigens, Surface / Q000032:analysis*; D001402:B-Lymphocytes / Q000276:immunology*; D002448:Cell Adhesion / Q000276:immunology; D002460:Cell Line; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000276:immunology*; D006801:Humans; D007124:Immunoenzyme Techniques; D007700:Kinetics; D007962:Leukocytes / Q000276:immunology; D008221:Lymphoid Tissue / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D014409:Tumor Necrosis Factor-alpha