Autoantibodies to the Protein Core of Vascular Basement Membrane Heparan Sulfate Proteoglycan in Systemic Lupus Erythematosus

Vascular heparan sulfate proteoglycan (vHSPG) has an important role in the normal vasculature, including hemostasis, lipolysis and other vascular functions. These functions are mediated by both the glycosarninogly-can and protein core moieties of vHSPG. Autoimmunity to vHSPG has been demonstrated to play a role in vascular injury in animal models, and is present in patients with autoimmune vascular disease. However, most previous studies of human autoimmunity to vHSPG have only investigated heparan sulfate glycosaminoglycan epitopes. In the current investigations. autoantibodies to the protein core of vHSPG in sera from patients with systemic lupus erythematosus (SLE) were investigated. vHSPG protein core was prepared by chemical deglycosylation. Competitive immunoinhibition ELISA and immunoblotting imrnuno-assays were established employing monoclonal antibodies to vHSPG protein core. SLE sera were demonstrated to contain IgG autoantibodies reactive with the vHSPG protein core by immunoblotting. Human aut...