title: Glycosylation of synthetic T helper cell epitopic peptides influences their antigenic potency and conformation in a sugar location-specific manner.
abstract: The immunodominant T helper cell epitopes 31D and VF13N of rabies virus nucleoprotein and glycoprotein, respectively, correspond to peptide sequences AVYTRIMMNGGRLKR and VVEDEGCTNLSGF, and are expressed between amino acids 404-418 and 29-41, of the appropriate proteins. We investigated how internal or external glycosylation affects the biological activity and conformation of the peptides 31D and VF13N. Mid-chain incorporation of maltobiose or N-acetylglucosamine moieties into the asparagine residues greatly diminished the T-cell stimulatory activity in vitro (due to the diminished ability of the glycopeptides to bind to major histocompatibility complex determinants) and reduced the characteristic alpha-helicity of the peptides in aqueous trifluoroethanol solutions. In contrast, addition of maltobiose- or N-acetylglucosamine-coupled asparagines to the N-termini of peptides 31D and VF13N resulted in unchanged T-cell activity. Furthermore, N-terminal glycosylation of peptide 31D, as indicated by the functional assay, decreased the sensitivity of the peptide to degradation in human serum and did not affect the alpha-helical conformation. These data indicate that glycosylation of T-cell epitopes is not a preferable method for the preparation of antagonists, but incorporation of the sugars to appropriate positions may be advantageous in the design of T-cell agonists and peptide-based vaccines.
authors.affiliation: Wistar Institute, Philadelphia, PA 19104.
authors.forename: L
authors.initials: L
authors.lastname: Otvos
authors.forename: L
authors.initials: L
authors.lastname: Urge
authors.forename: Z Q
authors.initials: ZQ
authors.lastname: Xiang
authors.forename: G R
authors.initials: GR
authors.lastname: Krivulka
authors.forename: L
authors.initials: L
authors.lastname: Nagy
authors.forename: G I
authors.initials: GI
authors.lastname: Szendrei
authors.forename: H C
authors.initials: HC
authors.lastname: Ertl
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002241:Carbohydrates / Q000737:chemistry* / Q000276:immunology; D002460:Cell Line; D015195:Drug Design; D000939:Epitopes / Q000276:immunology*; D020689:Exopeptidases; D005260:Female; D019204:GTP-Binding Proteins / Q000276:immunology; D006020:Glycopeptides / Q000276:immunology* / Q000494:pharmacology; D006023:Glycoproteins / Q000737:chemistry* / Q000276:immunology; D006031:Glycosylation; D036341:Intercellular Signaling Peptides and Proteins; D051379:Mice; D008809:Mice, Inbred C3H; D008969:Molecular Sequence Data; D009698:Nucleoproteins / Q000737:chemistry* / Q000276:immunology; D010447:Peptide Hydrolases; D011487:Protein Conformation; D006377:T-Lymphocytes, Helper-Inducer / Q000187:drug effects / Q000276:immunology*
chemical_list: D002241:Carbohydrates; D000939:Epitopes; D006020:Glycopeptides; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; D009698:Nucleoproteins; C090319:peptide 31D; C090318:peptide VF13N; D020689:Exopeptidases; D010447:Peptide Hydrolases; D019204:GTP-Binding Proteins