RECOMBINANT IMMUNOTOXIN COMPOSED OF A SINGLE CHAIN ANTIBODY REACTING WITH THE HUMAN TRANSFERRIN RECEPTOR AND DIPHTHERIA TOXIN

摘要

Single chain immunotoxins directed at the human transferrin receptor using PCR based methods are described. Anti-TFR(Fv)-PE40 contains DNA for the antigen binding portion (Fv) of a monoclonal antibody directed at the human transferrin receptor fused to the DNA for a 40,000 molecular weight fragment of Pseudomonas exotoxin (PE40). In another fusion protein, DT388-anti-TFR(Fv), DNA for the antigen binding portions of the anti-TFR antibody has been fused to the DNA encoding a truncated form of Diphtheria toxin. In anti-TFR(Fv)-PE40, the single chain antibody precedes the toxin whereas in DT388-anti-TFR(Fv) the single chain antibody is at the carboxyl end of toxin. The proteins encoded by these gene fusions were expressed in E. coli and purified by conventional chromatographic techniques to near homogeneity.