Abstract
Using albumin as the intermediate drug carrier, adriamycin (ADM) was conjugated with a monoclonal antibody (MoAb) S1 (IgG2a), which recognizes the antigenic determinant of the carbohydrate moiety expressed on human hepatocellular carcinoma cells. Selective cytotoxicity of MoAb S1-ADM conjugate was observed against S1 antigen positive c-Hc-4 hepatoma cells in vitro. In vivo experiments demonstrated that the conjugate significantly suppressed the human hepatoma line transplanted s. c. into nude mice. Autoradiographic examination of S1-14C-ADM conjugate revealed that the 14C-ADM accumulated in the tumor mass. Increase of the uptake of 125I-labeled conjugate by c-Hc-4 hepatoma cells was observed after incubation of the cells with the conjugate at 37°C, but not at 0°C, suggesting the cells actively internalize the conjugate in the course of time. Flow cytometric analysis also suggested that the cells internalize the conjugate 15 to 30 min. after incubation.
