title: Therapeutic assessment of SEED: a new engineered antibody platform designed to generate mono- and bispecific antibodies.
abstract: The strand-exchange engineered domain (SEED) platform was designed to generate asymmetric and bispecific antibody-like molecules, a capability that expands therapeutic applications of natural antibodies. This new protein engineered platform is based on exchanging structurally related sequences of immunoglobulin within the conserved CH3 domains. Alternating sequences from human IgA and IgG in the SEED CH3 domains generate two asymmetric but complementary domains, designated AG and GA. The SEED design allows efficient generation of AG/GA heterodimers, while disfavoring homodimerization of AG and GA SEED CH3 domains. Using a clinically validated antibody (C225), we tested whether Fab derivatives constructed on the SEED platform retain desirable therapeutic antibody features such as in vitro and in vivo stability, favorable pharmacokinetics, ligand binding and effector functions including antibody-dependent cell-mediated cytotoxicity and complement-dependent cytotoxicity. In addition, we tested SEED with combinations of binder domains (scFv, VHH, Fab). Mono- and bivalent Fab-SEED fusions retain full binding affinity, have excellent biochemical and biophysical stability, and retain desirable antibody-like characteristics conferred by Fc domains. Furthermore, SEED is compatible with different combinations of Fab, scFv and VHH domains. Our assessment shows that the new SEED platform expands therapeutic applications of natural antibodies by generating heterodimeric Fc-analog proteins.
authors.affiliation: EMD Serono Research Institute, Inc, One Technology Place, Rockland, MA 02370, USA.
authors.forename: Marco
authors.initials: M
authors.lastname: Muda
authors.forename: Alec W
authors.initials: AW
authors.lastname: Gross
authors.forename: Jessica P
authors.initials: JP
authors.lastname: Dawson
authors.forename: Chaomei
authors.initials: C
authors.lastname: He
authors.forename: Emmi
authors.initials: E
authors.lastname: Kurosawa
authors.forename: Rene
authors.initials: R
authors.lastname: Schweickhardt
authors.forename: Melanie
authors.initials: M
authors.lastname: Dugas
authors.forename: Maria
authors.initials: M
authors.lastname: Soloviev
authors.forename: Anna
authors.initials: A
authors.lastname: Bernhardt
authors.forename: David
authors.initials: D
authors.lastname: Fischer
authors.forename: John S
authors.initials: JS
authors.lastname: Wesolowski
authors.forename: Christie
authors.initials: C
authors.lastname: Kelton
authors.forename: Berend
authors.initials: B
authors.lastname: Neuteboom
authors.forename: Bjoern
authors.initials: B
authors.lastname: Hock
mesh_terms: D000818:Animals; D018033:Antibodies, Bispecific / Q000737:chemistry / Q000235:genetics* / Q000276:immunology* / Q000627:therapeutic use; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000235:genetics / Q000276:immunology / Q000627:therapeutic use; D000915:Antibody Affinity; D000918:Antibody Specificity; D045744:Cell Line, Tumor; D003165:Complement System Proteins / Q000276:immunology; D066246:ErbB Receptors / Q000276:immunology; D006207:Half-Life; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D007074:Immunoglobulin G / Q000235:genetics; D008297:Male; D051379:Mice; D015202:Protein Engineering / Q000379:methods*; D055503:Protein Multimerization; D055550:Protein Stability; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary
chemical_list: D018033:Antibodies, Bispecific; D000911:Antibodies, Monoclonal; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D003165:Complement System Proteins; D066246:ErbB Receptors