Immunotoxins for Brain Tumor Therapy

Abstract

Cancer cells can be specifically killed by a class of therapeutic molecules called immunotoxins that combine the potent toxicity of natural plant and bacterial proteins with the tumor-specific binding capacity of monoclonal antibodies. Toxins such as ricin and diphtheria toxin have been linked to new cell surface binding moieties in order to target tumor cells for destruction. To the extent that tumor cells have cell surface receptors that distinguish them from normal and essential cells, immunotoxins can be considered as potential reagents for cancer therapy. Tumor cell specific ligands, such as growth factors or monoclonal antibodies, can be linked to protein toxins by random chemical modification of lysine or sulfhydral residues (Vitetta et al. 1987) or by fusion of the new protein domains at the COOH- or NH₂-terminal of the protein by molecular biology techniques (Pastan et al. 1986).