title: Biological properties of a human compact anti-ErbB2 antibody.
abstract: ErbB2 is a prognostic factor and target of therapy for many carcinomas. In contrast with the other ErbB receptors, ErbB2 lacks a soluble direct ligand, but it is the preferred co-receptor for the ErbB family members, forming heterodimers with more potent and prolonged signalling activity than that of homodimers. We recently produced a new anti-ErbB2 antibody, Erb-hcAb, by fusion of Erbicin, a human, anti-ErbB2 scFv, selectively cytotoxic to ErbB2-positive cells, and a human Fc domain. This fully human antitumour antibody represents a compact version of an IgG1, with the cytotoxicity of the scFv moiety on target cells, combined with the ability of the Fc moiety to induce both antibody- and complement-dependent cytotoxicity. Here, we describe the main properties of Erb-hcAb, using as a reference Herceptin, an anti-ErbB2 humanized monoclonal currently employed in clinical immunotherapy. We found that both bivalent Erb-hcAb and Herceptin increase receptor phosphorylation and downregulation, whereas monovalent Erbicin does not. These results correlate with the finding that Erb-hcAb is capable of inducing apoptosis and inhibiting cell cycle progression in ErbB2-positive cells. Its powerful in vitro antitumour action matched that observed in vivo in experiments with human ErbB2-positive tumour xenografts established in athymic mice. Finally, Erb-hcAb displays a glycosylation profile virtually superimposable to that of a human IgG. These findings suggest that Erb-hcAb is a very promising new agent for the immunotherapy of carcinomas that overexpress the ErbB2 receptor.
authors.affiliation: Department of Structural and Functional Biology, University of Naples Federico II, Naples, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: De Lorenzo
authors.forename: Rosanna
authors.initials: R
authors.lastname: Cozzolino
authors.forename: Andrea
authors.initials: A
authors.lastname: Carpentieri
authors.forename: Piero
authors.initials: P
authors.lastname: Pucci
authors.forename: Paolo
authors.initials: P
authors.lastname: Laccetti
authors.forename: Giuseppe
authors.initials: G
authors.lastname: D'Alessio
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology* / Q000627:therapeutic use; D061067:Antibodies, Monoclonal, Humanized; D017209:Apoptosis; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor / Q000187:drug effects; D005260:Female; D006801:Humans; D015151:Immunoblotting; D007074:Immunoglobulin G / Q000276:immunology; D007135:Immunoglobulin Variable Region / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009374:Neoplasms, Experimental / Q000276:immunology / Q000473:pathology / Q000517:prevention & control*; D010766:Phosphorylation; D016133:Polymerase Chain Reaction; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000494:pharmacology* / Q000627:therapeutic use; D000068878:Trastuzumab
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D007074:Immunoglobulin G; D007135:Immunoglobulin Variable Region; D018719:Erb-b2 Receptor Tyrosine Kinases; D011993:Recombinant Fusion Proteins; D000068878:Trastuzumab