Crystal structure of a soluble CD28-Fab complex
Evans, E.J., 
Esnouf, R.M., 
Manso-Sancho, R., 
Gilbert, R.J.C., 
James, J.R., 
Yu, C., 
Fennelly, J.A., 
Vowles, C., 
Hanke, T., 
Walse, B., 
Hunig, T., 
Sorensen, P., 
Stuart, D.I., 
Davis, S.J.(2005) Nat Immunol 6: 271-279
- PubMed: 15696168 Search on PubMed
- DOI: https://doi.org/10.1038/ni1170
- Primary Citation of Related Structures:  
1YJD
- PubMed Abstract: 
Naive T cell activation requires signaling by the T cell receptor and by nonclonotypic cell surface receptors. The most important costimulatory protein is the monovalent homodimer CD28, which interacts with CD80 and CD86 expressed on antigen-presenting cells. Here we present the crystal structure of a soluble form of CD28 in complex with the Fab fragment of a mitogenic antibody. Structural comparisons redefine the evolutionary relationships of CD28-related proteins, antigen receptors and adhesion molecules and account for the distinct ligand-binding and stoichiometric properties of CD28 and the related, inhibitory homodimer CTLA-4. Cryo-electron microscopy-based comparisons of complexes of CD28 with mitogenic and nonmitogenic antibodies place new constraints on models of antibody-induced receptor triggering. This work completes the initial structural characterization of the CD28-CTLA-4-CD80-CD86 signaling system.
Organizational Affiliation: Nuffield Department of Clinical Medicine, The University of Oxford, John Radcliffe Hospital, Headington, Oxford, OX3 9DU, UK.