Human monoclonal anti-endothelial cell IgG-derived from a systemic lupus erythematosus patient binds and activates human endothelium in vitro.
Our objectives were to obtain monoclonal anti-endothelial cell antibodies (AECA) from systemic lupus erythematosus (SLE) patients, to characterize their antigen specificity, and their capability to induce a pro-inflammatory and pro-adhesive endothelial phenotype, and to investigate the mechanism of endothelial cell (EC) activation in vitro. Monoclonal IgG AECA were generated by hybridoma formation with human SLE B cells. Antigen specificity was characterized by immunoblotting with enriched cell membrane fractions, by cytofluorimetry and by cell solid-phase ELISA. Endothelial activation was evaluated by measuring increases in U937 cell adhesiveness, adhesion molecule (E-selectin and ICAM-1) expression and IL-6 production. In addition, mechanisms of endothelial activation were investigated by assessment of NF-kappaB by measuring the loss of its inhibitor I-kappaB. mAb E-3 bound live EC and recognized a 42 kDa EC membrane protein, it enhanced U937 adhesiveness, E-selectin and ICAM-1 expression and IL-6 production, and caused the loss of I-kappaB. We conclude this is the first in vitro demonstration that a human monoclonal AECA from a SLE patient reacts with a constitutive endothelial membrane antigen and induces a pro-inflammatory endothelial phenotype through NF-kappaB activation.
Department of Biomedical Sciences, University of Bradford, Bradford BD7 1DP, UK.
Z A
ZA
Yazici
E
E
Raschi
A
A
Patel
C
C
Testoni
M O
MO
Borghi
A M
AM
Graham
P L
PL
Meroni
N
N
Lindsey
D000911:Antibodies, Monoclonal / Q000276:immunology*; D000918:Antibody Specificity; D001323:Autoantibodies / Q000276:immunology* / Q000302:isolation & purification; D001327:Autoimmune Diseases / Q000276:immunology*; D002448:Cell Adhesion; D002478:Cells, Cultured; D019040:E-Selectin / Q000096:biosynthesis; D004730:Endothelium, Vascular / Q000166:cytology / Q000276:immunology*; D004789:Enzyme Activation; D005786:Gene Expression Regulation; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism; D007074:Immunoglobulin G / Q000276:immunology* / Q000302:isolation & purification; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis; D015850:Interleukin-6 / Q000096:biosynthesis; D048031:JNK Mitogen-Activated Protein Kinases; D008180:Lupus Erythematosus, Systemic / Q000150:complications / Q000276:immunology*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D014158:Transcription, Genetic; D020298:U937 Cells; D014470:Umbilical Cord; D014657:Vasculitis / Q000209:etiology / Q000276:immunology
D000911:Antibodies, Monoclonal; D001323:Autoantibodies; D019040:E-Selectin; D020672:I-kappa B Proteins; D007074:Immunoglobulin G; D015850:Interleukin-6; D016328:NF-kappa B; D018799:Intercellular Adhesion Molecule-1; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases