title: A cytokine-neutralizing antibody as a structural mimetic of 2 receptor interactions.
abstract: TGF-beta isoforms are key modulators of a broad range of biological pathways and increasingly are exploited as therapeutic targets. Here, we describe the crystal structures of a pan-TGF-beta neutralizing antibody, GC-1008, alone and in complex with TGF-beta3. The antibody is currently in clinical evaluation for idiopathic pulmonary fibrosis, melanoma, and renal cell cancer. GC-1008 recognizes an asymmetric binding interface across the TGF-beta homodimer with high affinity. Whereas both cognate receptors, TGF-beta-receptor types I and II, are required to recognize all 3 TGF-beta isoforms, GC-1008 has been engineered to bind with high affinity to TGF-beta1, 2, and 3 via a single interaction surface. Comparison with existing structures and models of TGF-beta interaction with its receptors suggests that the antibody binds to a similar epitope to the 2 receptors together and is therefore a structurally different but functionally identical mimic of the binding mode of both receptors.
authors.affiliation: Biochemisches Institut, Universität Zürich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Grütter
authors.forename: Trevor
authors.initials: T
authors.lastname: Wilkinson
authors.forename: Richard
authors.initials: R
authors.lastname: Turner
authors.forename: Sadhana
authors.initials: S
authors.lastname: Podichetty
authors.forename: Donna
authors.initials: D
authors.lastname: Finch
authors.forename: Matthew
authors.initials: M
authors.lastname: McCourt
authors.forename: Scott
authors.initials: S
authors.lastname: Loning
authors.forename: Lutz
authors.initials: L
authors.lastname: Jermutus
authors.forename: Markus G
authors.initials: MG
authors.lastname: Grütter
mesh_terms: D000906:Antibodies / Q000378:metabolism*; D016207:Cytokines / Q000276:immunology*; D000939:Epitopes; D006801:Humans; D018716:Molecular Mimicry; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D000077293:Receptor, Transforming Growth Factor-beta Type I; D000077294:Receptor, Transforming Growth Factor-beta Type II; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000276:immunology; D053773:Transforming Growth Factor beta1 / Q000378:metabolism; D053781:Transforming Growth Factor beta2 / Q000378:metabolism; D053782:Transforming Growth Factor beta3 / Q000378:metabolism
chemical_list: D000906:Antibodies; D016207:Cytokines; D000939:Epitopes; D018125:Receptors, Transforming Growth Factor beta; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D053781:Transforming Growth Factor beta2; D053782:Transforming Growth Factor beta3; D017346:Protein Serine-Threonine Kinases; D000077293:Receptor, Transforming Growth Factor-beta Type I; D000077294:Receptor, Transforming Growth Factor-beta Type II