Disulfide Bond Engineering to Trap Peptides in the MHC Class I Binding Groove

• Published in: Journal of Immunology Vol. 178; no. 10; pp. 6280 - 6289
• Main Authors: Truscott, Steven M, Lybarger, Lonnie, Martinko, John M, Mitaksov, Vesselin E, Kranz, David M, Connolly, Janet M, Fremont, Daved H, Hansen, Ted H
• Format: Journal Article
• Language: English
• Published: United States Am Assoc Immnol 15.05.2007
• Subjects: Amino Acid Sequence; Animals; Binding, Competitive - genetics; Binding, Competitive - immunology; Disulfides - chemistry; Disulfides - metabolism; Histocompatibility Antigens Class I - chemistry; Histocompatibility Antigens Class I - genetics; Histocompatibility Antigens Class I - metabolism; L Cells (Cell Line); Mice; Mice, Inbred C57BL; Mice, Knockout; Molecular Sequence Data; Peptides - chemistry; Peptides - genetics; Peptides - metabolism; Protein Binding - genetics; Protein Binding - immunology; Protein Engineering - methods
• ISSN: 0022-1767; 1550-6606; 1365-2567
• DOI: 10.4049/jimmunol.178.10.6280

Immunodominant peptides in CD8 T cell responses to pathogens and tumors are not always tight binders to MHC class I molecules. Furthermore, antigenic peptides that bind weakly to the MHC can be problematic when designing vaccines to elicit CD8 T cells in vivo or for the production of MHC multimers for enumerating pathogen-specific T cells in vitro. Thus, to enhance peptide binding to MHC class I, we have engineered a disulfide bond to trap antigenic peptides into the binding groove of murine MHC class I molecules expressed as single-chain trimers or SCTs. These SCTs with disulfide traps, termed dtSCTs, oxidized properly in the endoplasmic reticulum, transited to the cell surface, and were recognized by T cells. Introducing a disulfide trap created remarkably tenacious MHC/peptide complexes because the peptide moiety of the dtSCT was not displaced by high-affinity competitor peptides, even when relatively weak binding peptides were incorporated into the dtSCT. This technology promises to be useful for DNA vaccination to elicit CD8 T cells, in vivo study of CD8 T cell development, and construction of multivalent MHC/peptide reagents for the enumeration and tracking of T cells-particularly when the antigenic peptide has relatively weak affinity for the MHC.