title: Discovery of a junctional epitope antibody that stabilizes IL-6 and gp80 protein:protein interaction and modulates its downstream signaling.
abstract: Protein:protein interactions are fundamental in living organism homeostasis. Here we introduce VHH6, a junctional epitope antibody capable of specifically recognizing a neo-epitope when two proteins interact, albeit transiently, to form a complex. Orthogonal biophysical techniques have been used to prove the "junctional epitope" nature of VHH6, a camelid single domain antibody recognizing the IL-6-gp80 complex but not the individual components alone. X-ray crystallography, HDX-MS and SPR analysis confirmed that the CDR regions of VHH6 interact simultaneously with IL-6 and gp80, locking the two proteins together. At the cellular level, VHH6 was able to alter the response of endothelial cells to exogenous IL-6, promoting a sustained STAT3 phosphorylation signal, an accumulation of IL-6 in vesicles and an overall pro-inflammatory phenotype supported further by transcriptomic analysis. Junctional epitope antibodies, like VHH6, not only offer new opportunities in screening and structure-aided drug discovery, but could also be exploited as therapeutics to modulate complex protein:protein interactions.
authors.affiliation: New Medicines, UCB-Celltech, 208 Bath Road, SL1 3WE, Slough UK.
authors.forename: Ralph
authors.initials: R
authors.lastname: Adams
authors.affiliation: New Medicines, UCB-Celltech, 208 Bath Road, SL1 3WE, Slough UK.
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Burnley
authors.affiliation: New Medicines, UCB-Celltech, 208 Bath Road, SL1 3WE, Slough UK.
authors.forename: Chiara R
authors.initials: CR
authors.lastname: Valenzano
authors.affiliation: New Medicines, UCB-Celltech, 208 Bath Road, SL1 3WE, Slough UK.
authors.forename: Omar
authors.initials: O
authors.lastname: Qureshi
authors.affiliation: New Medicines, UCB-Celltech, 208 Bath Road, SL1 3WE, Slough UK.
authors.forename: Carl
authors.initials: C
authors.lastname: Doyle
authors.affiliation: New Medicines, UCB-Celltech, 208 Bath Road, SL1 3WE, Slough UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Lumb
authors.affiliation: New Medicines, UCB-Celltech, 208 Bath Road, SL1 3WE, Slough UK.
authors.forename: Maria
authors.initials: M
authors.lastname: Del Carmen Lopez
authors.affiliation: New Medicines, UCB-Celltech, 208 Bath Road, SL1 3WE, Slough UK.
authors.forename: Robert
authors.initials: R
authors.lastname: Griffin
authors.affiliation: New Medicines, UCB-Celltech, 208 Bath Road, SL1 3WE, Slough UK.
authors.forename: David
authors.initials: D
authors.lastname: McMillan
authors.affiliation: New Medicines, UCB-Celltech, 208 Bath Road, SL1 3WE, Slough UK.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Taylor
authors.affiliation: New Medicines, UCB-Celltech, 208 Bath Road, SL1 3WE, Slough UK.
authors.forename: Chris
authors.initials: C
authors.lastname: Meier
authors.affiliation: New Medicines, UCB-Celltech, 208 Bath Road, SL1 3WE, Slough UK.
authors.forename: Prashant
authors.initials: P
authors.lastname: Mori
authors.affiliation: New Medicines, UCB-Celltech, 208 Bath Road, SL1 3WE, Slough UK.
authors.forename: Laura M
authors.initials: LM
authors.lastname: Griffin
authors.affiliation: Central Veterinary Research Laboratory, P.O.Box 597, Dubai, United Arab Emirates.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Wernery
authors.affiliation: Central Veterinary Research Laboratory, P.O.Box 597, Dubai, United Arab Emirates.
authors.forename: Jörg
authors.initials: J
authors.lastname: Kinne
authors.affiliation: New Medicines, UCB-Celltech, 208 Bath Road, SL1 3WE, Slough UK.
authors.forename: Stephen
authors.initials: S
authors.lastname: Rapecki
authors.affiliation: New Medicines, UCB-Celltech, 208 Bath Road, SL1 3WE, Slough UK.
authors.forename: Terry S
authors.initials: TS
authors.lastname: Baker
authors.affiliation: New Medicines, UCB-Celltech, 208 Bath Road, SL1 3WE, Slough UK.
authors.forename: Alastair D G
authors.initials: AD
authors.lastname: Lawson
authors.affiliation: New Medicines, UCB-Celltech, 208 Bath Road, SL1 3WE, Slough UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Wright
authors.affiliation: New Medicines, UCB-Celltech, 208 Bath Road, SL1 3WE, Slough UK.
authors.forename: Anna
authors.initials: A
authors.lastname: Ettorre
mesh_terms: D000818:Animals; D000906:Antibodies / Q000737:chemistry* / Q000276:immunology; D016466:CHO Cells; D002162:Camelus / Q000276:immunology; D003412:Cricetulus; D018604:Epitope Mapping; D020869:Gene Expression Profiling; D057809:HEK293 Cells; D006801:Humans; D015850:Interleukin-6 / Q000276:immunology*; D010766:Phosphorylation; D017434:Protein Structure, Tertiary; D019947:Receptors, Interleukin-6 / Q000276:immunology*; D050796:STAT3 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D000906:Antibodies; D015850:Interleukin-6; D019947:Receptors, Interleukin-6; D050796:STAT3 Transcription Factor