CYTOTOXIC EFFECT OF IMMUNOCONJUGATE COMPOSED OF GLUCOSE-OXIDASE COUPLED TO AN ANTIGANGLIOSIDE (G(D2)) ANTIBODY ON SPHEROIDS

As a new treatment protocol for neuroblastoma, the chimeric (human/mou se) antiganglioside G(D2) antibody ch14.18 is being clinically tested. To improve the therapeutic effect of the antibody alone we are curren tly investigating the cytotoxicity of glucose-oxidase coupled to the a ntibody chl4.18 on spheroids of the neuroblastoma cell line SK-N-LO. T he cytotoxic effect of glucose-oxidase is achieved by the production o f hydrogen-peroxide (H2O2) and probably by the following reaction of H 2O2 with iron to form hydrogen radicals (OH .). The cytotoxicity of gl ucose-oxidase was measured by two viability tests (MTT and WST 1). Aft er a 4 hour treatment of the spheroids with the immunoconjugate, a red uction of viability to 50% (MTT-test) and 25% (WST 1-test), respective ly, was obtained. The difference between the results of these two test s might be explained by the different measurement protocols.