[Production and preclinical use of a monoclonal immunotoxin against laryngeal cancer cells].

A basic problem in cancer chemotherapy is the lack of selectivity of present anti-cancer drugs. The application of hybridoma technology for laryngeal carcinomas could show that certain monoclonal antibodies react with surface antigens on intact laryngeal carcinoma cells, which are rare or non existent on other types of cells. In the present study synthesis and cytotoxic properties of a conjugate (immunotoxin) are demonstrated containing the toxic A chain from ricin coupled to a monoclonal antilaryngeal antibody. This conjugate is lethal only for cells containing the corresponding tumour-associated antigen at the cell surface of various head and neck carcinoma cell lines. The results indicate that the newly formed chimaeric molecules maintain both the antigen-binding capacity and their toxic properties and that minute amounts of the immunotoxin are effective in specifically killing living laryngeal carcinoma cells in vitro.