title: Mapping of conformational B cell epitopes within alpha-helical coiled coil proteins.
abstract: An approach to mapping antigenic B cell epitopes within alpha-helical coiled coil proteins has been developed and applied to two proteins: Streptococcal M protein and C. elegans paramyosin protein UNC-15. Overlapping peptides derived from an alpha-helical coiled coil conformational epitope were embedded between helical flanking peptides derived from the completely unrelated GCN4 leucine zipper peptide. The resulting chimeric peptides exhibited helical propensity. Chimeric peptides were tested for antigenicity (recognition by antibody) or immunogenicity (production of appropriate antibody response). A conformational epitope within the Streptococcal M protein recognised by three mAbs spanned 12 residues. Analysis of chimeric peptides based on C. elegans UNC-15 has enabled fine mapping of the minimal B cell epitope recognised by monoclonal antibody NE1-6B2 to seven non-contiguous residues (spanning 15 residues); the footprint of contact residues involved in antibody recognition being restricted to the hydrophilic face of the helix and covering five helical turns. This chimeric peptide epitope when coupled to diphtheria toxoid was highly immunogenic in mice and antisera recognised the conformationally dependent native peptide epitope. This approach has the potential to map conformational epitopes and design minimal epitopes for use as vaccine candidates.
authors.affiliation: Cooperative Research Centre for Vaccine Technology and Queensland Institute of Medical Research, Herston, Brisbane, Australia. juanC@qimr.edu.au
authors.forename: J A
authors.initials: JA
authors.lastname: Cooper
authors.forename: W
authors.initials: W
authors.lastname: Hayman
authors.forename: C
authors.initials: C
authors.lastname: Reed
authors.forename: H
authors.initials: H
authors.lastname: Kagawa
authors.forename: M F
authors.initials: MF
authors.lastname: Good
authors.forename: A
authors.initials: A
authors.lastname: Saul
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology; D000947:Antigens, Helminth / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins / Q000276:immunology* / Q000648:ultrastructure; D017173:Caenorhabditis elegans / Q000276:immunology; D002352:Carrier Proteins; D002942:Circular Dichroism; D018604:Epitope Mapping; D015801:Helminth Proteins / Q000276:immunology* / Q000648:ultrastructure; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000276:immunology* / Q000648:ultrastructure; D010455:Peptides / Q000276:immunology; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins / Q000276:immunology; D013291:Streptococcus / Q000276:immunology; D014335:Tropomyosin / Q000276:immunology* / Q000648:ultrastructure; D014614:Vaccines, Synthetic / Q000737:chemistry
chemical_list: D000942:Antigens, Bacterial; D000947:Antigens, Helminth; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D015801:Helminth Proteins; D009124:Muscle Proteins; D010455:Peptides; D011993:Recombinant Fusion Proteins; D014335:Tropomyosin; D014614:Vaccines, Synthetic; C014689:streptococcal M protein