title: TriFabs--Trivalent IgG-Shaped Bispecific Antibody Derivatives: Design, Generation, Characterization and Application for Targeted Payload Delivery.
abstract: TriFabs are IgG-shaped bispecific antibodies (bsAbs) composed of two regular Fab arms fused via flexible linker peptides to one asymmetric third Fab-sized binding module. This third module replaces the IgG Fc region and is composed of the variable region of the heavy chain (VH) fused to CH3 with "knob"-mutations, and the variable region of the light chain (VL) fused to CH3 with matching "holes". The hinge region does not contain disulfides to facilitate antigen access to the third binding site. To compensate for the loss of hinge-disulfides between heavy chains, CH3 knob-hole heterodimers are linked by S354C-Y349C disulphides, and VH and VL of the stem region may be linked via VH44C-VL100C disulphides. TriFabs which bind one antigen bivalent in the same manner as IgGs and the second antigen monovalent "in between" these Fabs can be applied to simultaneously engage two antigens, or for targeted delivery of small and large (fluorescent or cytotoxic) payloads.
authors.affiliation: Roche Pharma Research &amp; Early Development, Large Molecule Research, Roche Innovation Center Penzberg, D82377 Penzberg, Germany. klaus.mayer.km1@roche.com.
authors.forename: Klaus
authors.initials: K
authors.lastname: Mayer
authors.affiliation: Roche Pharma Research &amp; Early Development, Large Molecule Research, Roche Innovation Center Penzberg, D82377 Penzberg, Germany. annalenabaumann@web.de.
authors.forename: Anna-Lena
authors.initials: AL
authors.lastname: Baumann
authors.affiliation: Roche Pharma Research &amp; Early Development, Large Molecule Research, Roche Innovation Center Penzberg, D82377 Penzberg, Germany. michael.grote@roche.com.
authors.forename: Michael
authors.initials: M
authors.lastname: Grote
authors.affiliation: Roche Pharma Research &amp; Early Development, Large Molecule Research, Roche Innovation Center Penzberg, D82377 Penzberg, Germany. stefan.seeber@roche.com.
authors.forename: Stefan
authors.initials: S
authors.lastname: Seeber
authors.affiliation: Roche Pharma Research &amp; Early Development, Large Molecule Research, Roche Innovation Center Penzberg, D82377 Penzberg, Germany. hubert.kettenberger@roche.com.
authors.forename: Hubert
authors.initials: H
authors.lastname: Kettenberger
authors.affiliation: Roche Pharma Research &amp; Early Development, Large Molecule Research, Roche Innovation Center Penzberg, D82377 Penzberg, Germany. sebastian.breuer@roche.com.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Breuer
authors.affiliation: Roche Pharma Research &amp; Early Development, Large Molecule Research, Roche Innovation Center Penzberg, D82377 Penzberg, Germany. tobias.killian@roche.com.
authors.forename: Tobias
authors.initials: T
authors.lastname: Killian
authors.affiliation: Roche Pharma Research &amp; Early Development, Large Molecule Research, Roche Innovation Center Penzberg, D82377 Penzberg, Germany. wolfgangschaefer@onlinehome.de.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schäfer
authors.affiliation: Roche Pharma Research &amp; Early Development, Large Molecule Research, Roche Innovation Center Penzberg, D82377 Penzberg, Germany. ulrich.brinkmann@roche.com.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Brinkmann
mesh_terms: D018033:Antibodies, Bispecific / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D000915:Antibody Affinity / Q000276:immunology; D001665:Binding Sites; D004220:Disulfides / Q000737:chemistry; D004337:Drug Carriers; D016503:Drug Delivery Systems; D000939:Epitopes / Q000276:immunology; D005818:Genetic Engineering; D006801:Humans; D018796:Immunoconjugates / Q000276:immunology / Q000378:metabolism; D007140:Immunoglobulin Fab Fragments / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D007074:Immunoglobulin G / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D011485:Protein Binding; D055503:Protein Multimerization; D055550:Protein Stability; D013696:Temperature
chemical_list: D018033:Antibodies, Bispecific; D004220:Disulfides; D004337:Drug Carriers; D000939:Epitopes; D018796:Immunoconjugates; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G
keywords: CD33; GPC3; LeY; disulfide stabilization; imaging; knob-into-hole; payload delivery; saporin