Antibody-targeted photolysis: In vitro studies with Sn(IV) chlorin e6 valently bound to monoclonal antibodies using a modified extran carrier

A monoclonal antibody-dextran-Sn(IV) chlo-immunoconjugate was prepared by a technique involving site-specific covalent modification of the monoclonal anti-iligosaccharide moiety. Dextran carriers were synthesized with a single chain-terminal hydrazide group, which was used as the coupling point between the carrier and the monoclonal antibody carbohydrate. Selective in vitro photolysis of SK-MBL-2 human malignant melanoma cells was accomplished using several conjugates prepared from anti-melanoma 2.1 cromophore:antibody molar ratios, 6.8 and 11.2). Phototox-Italy, as measured by clonogenic assay, was dependent on the dellivered dose of 634-nm light and was observed only for conjugates that bound SK-MEL-2 cells. As judged by competalive inhibition radioimmunoassay, conjugates prepared in this hion showed excellent retention of antigen binding activity tive to the unmodified antibody. (.