Papers In Press, published online ahead of print February 15, 2006
J. Biol. Chem, 10.1074/jbc.M513415200
Submitted on December 16, 2005
Revised on February 14, 2006
Accepted on February 15, 2006
Single variable domain-IgG fusion: A novel recombinant approach to Fc domain-containing bispecific antibodies
Juqun Shen, Marie Danielle Vil, Xenia Jimenez, Michelle Iacolina, Haifan Zhang, and Zhenping Zhu
Molecular and Cell Biology, ImClone Systems Incorporated, New York, NY 10014
Corresponding Author: zhenping{at}imclone.com
Both laboratory and early clinical studies to date have demonstrated that bispecific antibodies (BsAb) may have significant potential application in cancer therapy. The clinical development of BsAb as therapeutics has, however, been hampered by the difficulty in preparing the materials in sufficient quantity and quality by traditional methods. In recent years, a variety of recombinant methods have been developed for efficient production of BsAb, both as antibody fragments and as full-length IgG-like molecules. Here we describe a novel recombinant approach for the production of an Fc domain-containing, IgG-like tetravalent BsAb, with two antigen-binding sites to each of its target antigens, by genetically fusing a single variable domain antibody to the N-terminus of the light chain of a functional IgG antibody of different specificity. A model BsAb was constructed using a single variable domain antibody to mouse platelet derived growth factor receptor alpha and a conventional IgG antibody to mouse vascular endothelial growth factor receptor 2. The BsAb was expressed in mammalian cells and purified to homogeneity by a one-step Protein A affinity chromatography. Further, the BsAb retains the antigen binding specificity and the receptor neutralizing activity of both of its parent antibodies. This design and expression of Fc domain-containing, IgG-like BsAb should be applicable to the construction of similar BsAb from antibodies recognizing any pairs of antigens.