title: Protection of cultured endothelial cells from hydrogen peroxide-induced injury by antibody-conjugated catalase.
abstract: The cytoprotective features of catalase-antibody conjugate prepared by covalent conjugation of catalase to rabbit antibody against mouse IgG is described. The bifunctional cross-linking agent m-maleimidobenzoic acid N-hydroxysuccinimide ester (MBS) was used for conjugation. Functionally active conjugate binds specifically to the plastic-adsorbed mouse IgG and to the surface of live human endothelial cells treated with mouse antiserum against human endothelial cells. Up to 4 units of catalase activity can bind to 1 cm2 of the endothelial monolayer. The targeted catalase protects endothelial cells from cytotoxic action of hydrogen peroxide: the minimal cytotoxic concentration of H2O2 for protected cells is 80-times higher than for intact cells. This effect is attributed partly to local reduction of H2O2 concentration in the cell microenvironment. Targeted catalase was estimated to reduce H2O2 concentration 8-fold near the cell surface with respect to average total concentration.
mesh_terms: D000906:Antibodies / Q000008:administration & dosage*; D002374:Catalase / Q000008:administration & dosage*; D002470:Cell Survival / Q000187:drug effects*; D002478:Cells, Cultured; D004727:Endothelium / Q000187:drug effects; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity*
chemical_list: D000906:Antibodies; D006861:Hydrogen Peroxide; D002374:Catalase