A possible role for metallic ions in the carbohydrate cluster recognition displayed by a lewis Y specific antibody

Background: Lewis Y (Ley) is a blood group-related carbohydrate that is expressed at high surface densities on the majority of epithelial carcinomas and is a promising target for antibody-based immunotherapy. A humanized Ley-specific antibody (hu3S193) has shown encouraging safety, pharmacokinetic a...

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Main Authors: Farrugia, W., Scott, A., Ramsland, Paul
Format: Journal Article
Published: Public Library of Science 2009
Online Access:http://hdl.handle.net/20.500.11937/44468
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author Farrugia, W.
Scott, A.
Ramsland, Paul
author_facet Farrugia, W.
Scott, A.
Ramsland, Paul
author_sort Farrugia, W.
building Curtin Institutional Repository
collection Online Access
description Background: Lewis Y (Ley) is a blood group-related carbohydrate that is expressed at high surface densities on the majority of epithelial carcinomas and is a promising target for antibody-based immunotherapy. A humanized Ley-specific antibody (hu3S193) has shown encouraging safety, pharmacokinetic and tumor-targeting properties in recently completed Phase I clinical trials. Methodology/Principal Findings: We report the three-dimensional structures for both the free (unliganded) and bound (Ley tetrasaccharide) hu3S193 Fab from the same crystal grown in the presence of divalent zinc ions. There is no evidence of significant conformational changes occurring in either the Ley carbohydrate antigen or the hu3S193 binding site, which suggests a rigid fit binding mechanism. In the crystal, the hu3S193 Fab molecules are coordinated at their protein-protein interface by two zinc ions and in solution aggregation of Fab can be initiated by zinc, but not magnesium ions. Dynamic light scattering revealed that zinc ions could initiate a sharp transition from hu3S193 Fab monomers to large multimeric aggregates in solution. Conclusions/Significance: Zinc ions can mediate interactions between hu3S193 Fab in crystals and in solution. Whether metallic ion mediated aggregation of antibody occurs in vivo is not known, but the present results suggest that similar clustering mechanisms could occur when hu3S193 binds to Ley on cells, particularly given the high surface densities of antigen on the target tumor cells. © 2009 Farrugia et al.
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spelling curtin-20.500.11937-444682017-09-13T14:13:03Z A possible role for metallic ions in the carbohydrate cluster recognition displayed by a lewis Y specific antibody Farrugia, W. Scott, A. Ramsland, Paul Background: Lewis Y (Ley) is a blood group-related carbohydrate that is expressed at high surface densities on the majority of epithelial carcinomas and is a promising target for antibody-based immunotherapy. A humanized Ley-specific antibody (hu3S193) has shown encouraging safety, pharmacokinetic and tumor-targeting properties in recently completed Phase I clinical trials. Methodology/Principal Findings: We report the three-dimensional structures for both the free (unliganded) and bound (Ley tetrasaccharide) hu3S193 Fab from the same crystal grown in the presence of divalent zinc ions. There is no evidence of significant conformational changes occurring in either the Ley carbohydrate antigen or the hu3S193 binding site, which suggests a rigid fit binding mechanism. In the crystal, the hu3S193 Fab molecules are coordinated at their protein-protein interface by two zinc ions and in solution aggregation of Fab can be initiated by zinc, but not magnesium ions. Dynamic light scattering revealed that zinc ions could initiate a sharp transition from hu3S193 Fab monomers to large multimeric aggregates in solution. Conclusions/Significance: Zinc ions can mediate interactions between hu3S193 Fab in crystals and in solution. Whether metallic ion mediated aggregation of antibody occurs in vivo is not known, but the present results suggest that similar clustering mechanisms could occur when hu3S193 binds to Ley on cells, particularly given the high surface densities of antigen on the target tumor cells. © 2009 Farrugia et al. 2009 Journal Article http://hdl.handle.net/20.500.11937/44468 10.1371/journal.pone.0007777 Public Library of Science unknown
spellingShingle Farrugia, W.
Scott, A.
Ramsland, Paul
A possible role for metallic ions in the carbohydrate cluster recognition displayed by a lewis Y specific antibody
title A possible role for metallic ions in the carbohydrate cluster recognition displayed by a lewis Y specific antibody
title_full A possible role for metallic ions in the carbohydrate cluster recognition displayed by a lewis Y specific antibody
title_fullStr A possible role for metallic ions in the carbohydrate cluster recognition displayed by a lewis Y specific antibody
title_full_unstemmed A possible role for metallic ions in the carbohydrate cluster recognition displayed by a lewis Y specific antibody
title_short A possible role for metallic ions in the carbohydrate cluster recognition displayed by a lewis Y specific antibody
title_sort possible role for metallic ions in the carbohydrate cluster recognition displayed by a lewis y specific antibody
url http://hdl.handle.net/20.500.11937/44468