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Lessons from the Crystal Structure of the S. aureus Surface Protein Clumping Factor A in Complex With Tefibazumab, an Inhibiting Monoclonal Antibody()

The Staphylococcus aureus fibrinogen binding MSCRAMM (Microbial Surface Components Recognizing Adhesive Matrix Molecules), ClfA (clumping factor A) is an important virulence factor in staphylococcal infections and a component of several vaccines currently under clinical evaluation. The mouse monoclo...

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Autores principales: Ganesh, Vannakambadi K., Liang, Xiaowen, Geoghegan, Joan A., Cohen, Ana Luisa V., Venugopalan, Nagarajan, Foster, Timothy J, Hook, Magnus
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Elsevier 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5264652/
https://www.ncbi.nlm.nih.gov/pubmed/27789272
http://dx.doi.org/10.1016/j.ebiom.2016.09.027
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author Ganesh, Vannakambadi K.
Liang, Xiaowen
Geoghegan, Joan A.
Cohen, Ana Luisa V.
Venugopalan, Nagarajan
Foster, Timothy J
Hook, Magnus
author_facet Ganesh, Vannakambadi K.
Liang, Xiaowen
Geoghegan, Joan A.
Cohen, Ana Luisa V.
Venugopalan, Nagarajan
Foster, Timothy J
Hook, Magnus
author_sort Ganesh, Vannakambadi K.
collection PubMed
description The Staphylococcus aureus fibrinogen binding MSCRAMM (Microbial Surface Components Recognizing Adhesive Matrix Molecules), ClfA (clumping factor A) is an important virulence factor in staphylococcal infections and a component of several vaccines currently under clinical evaluation. The mouse monoclonal antibody aurexis (also called 12-9), and the humanized version tefibazumab are therapeutic monoclonal antibodies targeting ClfA that in combination with conventional antibiotics were effective in animal models but showed less impressive efficacy in a limited Phase II clinical trial. We here report the crystal structure and a biochemical characterization of the ClfA/tefibazumab (Fab) complex. The epitope for tefibazumab is located to the “top” of the N3 subdomain of ClfA and partially overlaps with a previously unidentified second binding site for fibrinogen. A high-affinity binding of ClfA to fibrinogen involves both an interaction at the N3 site and the previously identified docking of the C-terminal segment of the fibrinogen γ-chain in the N2N3 trench. Although tefibazumab binds ClfA with high affinity we observe a modest IC(50) value for the inhibition of fibrinogen binding to the MSCRAMM. This observation, paired with a common natural occurring variant of ClfA that is not effectively recognized by the mAb, may partly explain the modest effect tefibazumab showed in the initial clinic trail. This information will provide guidance for the design of the next generation of therapeutic anti-staphylococcal mAbs targeting ClfA.
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spelling pubmed-52646522017-02-01 Lessons from the Crystal Structure of the S. aureus Surface Protein Clumping Factor A in Complex With Tefibazumab, an Inhibiting Monoclonal Antibody() Ganesh, Vannakambadi K. Liang, Xiaowen Geoghegan, Joan A. Cohen, Ana Luisa V. Venugopalan, Nagarajan Foster, Timothy J Hook, Magnus EBioMedicine Research Paper The Staphylococcus aureus fibrinogen binding MSCRAMM (Microbial Surface Components Recognizing Adhesive Matrix Molecules), ClfA (clumping factor A) is an important virulence factor in staphylococcal infections and a component of several vaccines currently under clinical evaluation. The mouse monoclonal antibody aurexis (also called 12-9), and the humanized version tefibazumab are therapeutic monoclonal antibodies targeting ClfA that in combination with conventional antibiotics were effective in animal models but showed less impressive efficacy in a limited Phase II clinical trial. We here report the crystal structure and a biochemical characterization of the ClfA/tefibazumab (Fab) complex. The epitope for tefibazumab is located to the “top” of the N3 subdomain of ClfA and partially overlaps with a previously unidentified second binding site for fibrinogen. A high-affinity binding of ClfA to fibrinogen involves both an interaction at the N3 site and the previously identified docking of the C-terminal segment of the fibrinogen γ-chain in the N2N3 trench. Although tefibazumab binds ClfA with high affinity we observe a modest IC(50) value for the inhibition of fibrinogen binding to the MSCRAMM. This observation, paired with a common natural occurring variant of ClfA that is not effectively recognized by the mAb, may partly explain the modest effect tefibazumab showed in the initial clinic trail. This information will provide guidance for the design of the next generation of therapeutic anti-staphylococcal mAbs targeting ClfA. Elsevier 2016-10-01 /pmc/articles/PMC5264652/ /pubmed/27789272 http://dx.doi.org/10.1016/j.ebiom.2016.09.027 Text en © 2016 Published by Elsevier B.V. http://creativecommons.org/licenses/by-nc-nd/4.0/ This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
spellingShingle Research Paper
Ganesh, Vannakambadi K.
Liang, Xiaowen
Geoghegan, Joan A.
Cohen, Ana Luisa V.
Venugopalan, Nagarajan
Foster, Timothy J
Hook, Magnus
Lessons from the Crystal Structure of the S. aureus Surface Protein Clumping Factor A in Complex With Tefibazumab, an Inhibiting Monoclonal Antibody()
title Lessons from the Crystal Structure of the S. aureus Surface Protein Clumping Factor A in Complex With Tefibazumab, an Inhibiting Monoclonal Antibody()
title_full Lessons from the Crystal Structure of the S. aureus Surface Protein Clumping Factor A in Complex With Tefibazumab, an Inhibiting Monoclonal Antibody()
title_fullStr Lessons from the Crystal Structure of the S. aureus Surface Protein Clumping Factor A in Complex With Tefibazumab, an Inhibiting Monoclonal Antibody()
title_full_unstemmed Lessons from the Crystal Structure of the S. aureus Surface Protein Clumping Factor A in Complex With Tefibazumab, an Inhibiting Monoclonal Antibody()
title_short Lessons from the Crystal Structure of the S. aureus Surface Protein Clumping Factor A in Complex With Tefibazumab, an Inhibiting Monoclonal Antibody()
title_sort lessons from the crystal structure of the s. aureus surface protein clumping factor a in complex with tefibazumab, an inhibiting monoclonal antibody()
topic Research Paper
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5264652/
https://www.ncbi.nlm.nih.gov/pubmed/27789272
http://dx.doi.org/10.1016/j.ebiom.2016.09.027
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