Epitope-dependent mechanisms of CD27 neutralization revealed by X-ray crystallography

Mol Immunol. 2017 Mar;83:92-99. doi: 10.1016/j.molimm.2017.01.005. Epub 2017 Jan 21.


CD27 is a T and B cell co-stimulatory protein of the TNF receptor superfamily dependent on the availability of the TNF-like ligand CD70. Two anti-CD27 neutralizing monoclonal antibodies were obtained from mouse hybridoma and subsequently humanized and optimized for binding the target. The two antibodies are similar in terms of their CD27-binding affinity and ability to block NF-κB signaling, however their clearance rates in monkeys are very different. The pharmacokinetics profiles could be epitope dependent. To identify the epitopes, we determined the crystal structure of the ternary complex between CD27 and the Fab fragments of these non-competing antibodies. The structure reveals the binding modes of the antibodies suggesting that their mechanisms of action are distinctly different and provides a possible explanation of the in vivo data.

Keywords: Antibody; CD27; Crystal structure; Epitope; Mechanism.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Antibodies, Monoclonal / chemistry*
  • Antibodies, Monoclonal / immunology
  • Antibodies, Monoclonal / pharmacokinetics*
  • Antibodies, Neutralizing / chemistry
  • Antibodies, Neutralizing / immunology
  • Antibody Affinity
  • CD27 Ligand / chemistry
  • CD27 Ligand / immunology
  • Crystallography, X-Ray
  • Enzyme-Linked Immunosorbent Assay
  • Epitopes, B-Lymphocyte / chemistry*
  • Epitopes, B-Lymphocyte / immunology*
  • Half-Life
  • Humans
  • Macaca fascicularis
  • Mice
  • Tumor Necrosis Factor Receptor Superfamily, Member 7 / immunology*


  • Antibodies, Monoclonal
  • Antibodies, Neutralizing
  • CD27 Ligand
  • Epitopes, B-Lymphocyte
  • Tumor Necrosis Factor Receptor Superfamily, Member 7