Specific killing of human endothelial cells by antibody-conjugated glucose oxidase

Conjugates of antibody with glucose oxidase obtained via the carbohydrate moiety of the enzyme via oxidation with periodate are suggested as a tool for selective killing of the target cell. The conjugate was separated from uncoupled enzyme by repeated precipitation with ammonium sulfate (42% saturation). Purity of the conjugate was estimated by gel filtration on Toya Pearl TP-65. The glucose oxidase conjugated with rabbit antibody against mouse IgG bound specifically to plastic-adsorbed mouse immunoglobulins and to cultured human endothelial cells pretreated with mouse anti-endothelial antiserum. Glucose oxidase targeted to the cells generates hydrogen peroxide in the presence of glucose. This hydrogen peroxide killed the endothelial cells even in the absence of a halide-peroxidase system and in the presence of catalase. Features of the conjugate (specificity, effective cytotoxicity, high stability) make it suitable for prospective in vivo application and for immunoselective segregation of heterogeneous cell populations.