title: Characterization of discontinuous epitope of prion protein recognized by the monoclonal antibody T2.
abstract: The anti-prion protein (PrP) monoclonal antibody T2 has previously been prepared using PrP-knockout mice immunized with mouse recombinant PrP residues 121-231, however its interaction mechanism to PrP antigen has not been cleared. Here we identified and characterized the epitope of T2 antibody. The competitive ELISA with 20-mer synthetic peptides derived from PrP121-231 showed that T2 antibody had no affinity for these peptides. The analysis with deletion mutants of PrP revealed that 10 amino acids in the N terminus and 66 amino acids in the C terminus of PrP121-231 were necessary for reactivity with T2. Two far regions are necessary for complete affinity of the T2 antibody for PrP; either region alone is not sufficient to retain the affinity. The epitope recognized by T2 antibody is discontinuous and conformational. We examined the effect of disulfide bond and salt bridges. Alkylation of cysteine residues in C terminus of PrP121-231, which breaks a disulfide bond and disrupts the structure, had diminished the reactivity. Mutations induced in the PrP121-231 to break the disulfide bond or salt bridges, markedly had reduced the reactivity with T2 antibody. It suggests that T2 antibody recognized the structure maintained by the disulfide bond and salt bridges.
authors.affiliation: Molecular Composite Medicine Research Group, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, 1-1-1, Higashi, Tsukuba-shi, Ibaraki 305-8566, Japan.
authors.forename: Eriko
authors.initials: E
authors.lastname: Sasamori
authors.forename: Sachiko
authors.initials: S
authors.lastname: Suzuki
authors.forename: Mieko
authors.initials: M
authors.lastname: Kato
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Tagawa
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Hanyu
mesh_terms: D000478:Alkylation; D000818:Animals; D000911:Antibodies, Monoclonal; D000937:Antigen-Antibody Reactions; D001483:Base Sequence; D001667:Binding, Competitive; D015153:Blotting, Western; D017931:DNA Primers / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000737:chemistry / Q000235:genetics; D066298:In Vitro Techniques; D051379:Mice; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D010084:Oxidation-Reduction; D010446:Peptide Fragments / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*; D011328:Prions / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D017931:DNA Primers; D000939:Epitopes; D010446:Peptide Fragments; D011328:Prions; D011994:Recombinant Proteins; C100569:prion protein (121-231)