title: Covalent linkage to beta2-microglobulin enhances the MHC stability and antigenicity of suboptimal CTL epitopes.
abstract: Many CTL epitopes of clinical importance, particularly those derived from tumor Ags, display relatively poor MHC binding affinity and stability. Because in vivo immunogenicity, and thus the efficacy of peptide-based vaccines, is thought to be determined by MHC/peptide complex stability, there is a need to develop a simple strategy for enhancing the binding of suboptimal epitopes. Toward this goal, the ability to enhance suboptimal peptides through covalent linkage to beta2-microglobulin (beta2m) was explored. Two suboptimal variants of a high-affinity Db-restricted influenza nucleoprotein peptide were covalently linked, via a polypeptide spacer, to the amino terminus of human beta2m and the recombinant fusion proteins expressed in Escherichia coli. When compared with their uncoupled counterparts, the beta2m-linked epitopes display enhanced MHC stabilization and antigenicity. Thus, tethering epitopes to beta2m provides a simple method for augmenting the biological activity of suboptimal peptides and could be useful in the design of peptide-based vaccines or immunotherapeutics.
authors.affiliation: Department of Immunology, Medical Sciences Building, University of Toronto, Toronto, Canada.
authors.forename: R A
authors.initials: RA
authors.lastname: Uger
authors.forename: S M
authors.initials: SM
authors.lastname: Chan
authors.forename: B H
authors.initials: BH
authors.lastname: Barber
mesh_terms: D000818:Animals; D000956:Antigens, Viral / Q000276:immunology*; D003602:Cytotoxicity, Immunologic; D015195:Drug Design; D000939:Epitopes / Q000235:genetics / Q000276:immunology; D006801:Humans; D008285:Major Histocompatibility Complex / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D009698:Nucleoproteins / Q000235:genetics / Q000276:immunology; D009975:Orthomyxoviridae / Q000235:genetics / Q000276:immunology; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014614:Vaccines, Synthetic; D014758:Viral Core Proteins / Q000235:genetics / Q000276:immunology; D001613:beta 2-Microglobulin / Q000235:genetics / Q000276:immunology*
chemical_list: D000956:Antigens, Viral; D000939:Epitopes; D009698:Nucleoproteins; D011993:Recombinant Fusion Proteins; D014614:Vaccines, Synthetic; D014758:Viral Core Proteins; D001613:beta 2-Microglobulin