Effects of Ricin A Chain Conjugates of Monoclonal Antibodies to Human α-Fetoprotein and Placental Alkaline Phosphatase on Antigen-producing Tumor Cells in Culture

摘要: Two tumor-associated proteins, α-fetoprotein (AFP) and placental alkaline phosphatase (PLAP), were investigated as target proteins for antibody:cytotoxin conjugates. An AFP-producing hepatoma cell line (HepG2) a PLAP-producing cervical carcinoma (SKGllla) used cells. Both lines equally susceptible to the toxic effects of intact ricin. Immunofluorescent studies showed that AFP could be detected at surface HepG2 cells in speckled distribution, while PLAP was uniformly distributed over SKGllla The anti-AFP ricin A chain conjugate not cytotoxic either low concentrations killed both types high concentrations. anti-PLAP 100-fold more than At concentrations, it also enhanced toxicity inhibited by an excess unconjugated but anti-AFP, indicating uptake depends on specific binding antigen. indiscriminate observed antibody, suggesting this effect independent identity These results emphasize importance properties antigen antibody conjugates well need caution experiments using They suggest may suitable immunotoxin therapy human cancer.