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Bispecific digoxigenin-binding antibodies for targeted payload delivery

By Silke Metz, Alexander K. Haas, Karin Daub, Rebecca Croasdale, Jan Stracke, Wilma Lau, Guy Georges, Hans-Peter Josel, Sebastian Dziadek, Karl-Peter Hopfner, Alfred Lammens, Werner Scheuer, Eike Hoffmann, Olaf Mundigl and Ulrich Brinkmann

Abstract

Bispecific antibodies that bind cell-surface targets as well as digoxigenin (Dig) were generated for targeted payload delivery. Targeting moieties are IgGs that bind the tumor antigens Her2, IGF1R, CD22, or LeY. A Dig-binding single-chain Fv was attached in disulfide-stabilized form to C termini of CH3 domains of targeting antibodies. Bispecific molecules were expressed in mammalian cells and purified in the same manner as unmodified IgGs. They are stable without aggregation propensity and retain binding specificity/affinity to cell-surface antigens and Dig. Digoxigeninylated payloads were generated that retain full functionality and can be complexed to bispecific antibodies in a defined 2∶1 ratio. Payloads include small compounds (Dig-Cy5, Dig-Doxorubicin) and proteins (Dig-GFP). Complexed payloads are targeted by the bispecifics to cancer cells and because these complexes are stable in serum, they can be applied for targeted delivery. Because Dig bispecifics also effectively capture digoxigeninylated compounds under physiological conditions, separate administration of uncharged Dig bispecifics followed by application of Dig payload is sufficient to achieve antibody-mediated targeting in vitro and in vivo

Topics: Biological Sciences
Publisher: National Academy of Sciences
OAI identifier: oai:pubmedcentral.nih.gov:3100918
Provided by: PubMed Central
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