title: Bispecific digoxigenin-binding antibodies for targeted payload delivery.
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 21 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.
authors.affiliation: Roche Pharma Research and Early Development, Biologics Engineering, D-82377 Penzberg, Germany.
authors.forename: Silke
authors.initials: S
authors.lastname: Metz
authors.forename: Alexander K
authors.initials: AK
authors.lastname: Haas
authors.forename: Karin
authors.initials: K
authors.lastname: Daub
authors.forename: Rebecca
authors.initials: R
authors.lastname: Croasdale
authors.forename: Jan
authors.initials: J
authors.lastname: Stracke
authors.forename: Wilma
authors.initials: W
authors.lastname: Lau
authors.forename: Guy
authors.initials: G
authors.lastname: Georges
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Josel
authors.forename: Sebastian
authors.initials: S
authors.lastname: Dziadek
authors.forename: Karl-Peter
authors.initials: KP
authors.lastname: Hopfner
authors.forename: Alfred
authors.initials: A
authors.lastname: Lammens
authors.forename: Werner
authors.initials: W
authors.lastname: Scheuer
authors.forename: Eike
authors.initials: E
authors.lastname: Hoffmann
authors.forename: Olaf
authors.initials: O
authors.lastname: Mundigl
authors.forename: Ulrich
authors.initials: U
authors.lastname: Brinkmann
mesh_terms: D018033:Antibodies, Bispecific / Q000276:immunology / Q000627:therapeutic use*; D000951:Antigens, Neoplasm / Q000276:immunology; D000970:Antineoplastic Agents / Q000008:administration & dosage*; D002232:Carbocyanines / Q000008:administration & dosage; D045744:Cell Line, Tumor; D004076:Digoxigenin / Q000276:immunology*; D004317:Doxorubicin / Q000008:administration & dosage; D016503:Drug Delivery Systems / Q000379:methods*; D049452:Green Fluorescent Proteins / Q000008:administration & dosage; D006801:Humans; D008722:Methods; D057127:Single-Chain Antibodies
chemical_list: D018033:Antibodies, Bispecific; D000951:Antigens, Neoplasm; D000970:Antineoplastic Agents; D002232:Carbocyanines; D057127:Single-Chain Antibodies; C085321:cyanine dye 5; D049452:Green Fluorescent Proteins; D004317:Doxorubicin; D004076:Digoxigenin