title: A novel pathogenic RBP-3 peptide reveals epitope spreading in persistent experimental autoimmune uveoretinitis.
abstract: Experimental autoimmune uveoretinitis (EAU) in the C57BL/6J mouse is a model of non-infectious posterior segment intraocular inflammation that parallels clinical features of the human disease. The purpose of this study was to analyse the immune response to the four murine subunits of retinol binding protein-3 (RBP-3) to identify pathogenic epitopes to investigate the presence of intramolecular epitope spreading during the persistent inflammation phase observed in this model of EAU. Recombinant murine subunits of the RBP-3 protein were purified and used to immunize C57BL/6J mice to induce EAU. An overlapping peptide library was used to screen RBP-3 subunit 3 for immunogenicity and pathogenicity. Disease phenotype and characterization of pathogenic subunits and peptides was undertaken by topical endoscopic fundal imaging, immunohistochemistry, proliferation assays and flow cytometry. RBP-3 subunits 1, 2 and 3 induced EAU in the C57BL/6J mice, with subunit 3 eliciting the most destructive clinical disease. Within subunit 3 we identified a novel uveitogenic epitope, 629-643. The disease induced by this peptide was comparable to that produced by the uveitogenic 1-20 peptide. Following immunization, peptide-specific responses by CD4(+) and CD8(+) T-cell subsets were detected, and cells from both populations were present in the retinal inflammatory infiltrate. Intramolecular epitope spreading between 629-643 and 1-20 was detected in mice with clinical signs of disease. The 629-643 RBP-3 peptide is a major uveitogenic peptide for the induction of EAU in C57BL/6J mice and the persistent clinical disease induced with one peptide leads to epitope spreading.
authors.affiliation: School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK.
authors.forename: Joanne
authors.initials: J
authors.lastname: Boldison
authors.affiliation: Academic Unit of Ophthalmology, School of Clinical Sciences, University of Bristol, Bristol, UK.
authors.forename: Tarnjit K
authors.initials: TK
authors.lastname: Khera
authors.affiliation: Academic Unit of Ophthalmology, School of Clinical Sciences, University of Bristol, Bristol, UK.
authors.forename: David A
authors.initials: DA
authors.lastname: Copland
authors.affiliation: Academic Unit of Ophthalmology, School of Clinical Sciences, University of Bristol, Bristol, UK.
authors.forename: Madeleine L
authors.initials: ML
authors.lastname: Stimpson
authors.affiliation: Academic Unit of Ophthalmology, School of Clinical Sciences, University of Bristol, Bristol, UK.
authors.forename: Gemma L
authors.initials: GL
authors.lastname: Crawford
authors.affiliation: School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK.|Academic Unit of Ophthalmology, School of Clinical Sciences, University of Bristol, Bristol, UK.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Dick
authors.affiliation: School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK.|Academic Unit of Ophthalmology, School of Clinical Sciences, University of Bristol, Bristol, UK.
authors.forename: Lindsay B
authors.initials: LB
authors.lastname: Nicholson
mesh_terms: D000818:Animals; D001327:Autoimmune Diseases / Q000276:immunology* / Q000473:pathology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D049109:Cell Proliferation; D002478:Cells, Cultured; D004195:Disease Models, Animal; D018604:Epitope Mapping; D000939:Epitopes / Q000235:genetics / Q000276:immunology*; D005136:Eye Proteins / Q000235:genetics / Q000276:immunology*; D005260:Female; D006801:Humans; D008213:Lymphocyte Activation; D008810:Mice, Inbred C57BL; D010446:Peptide Fragments / Q000235:genetics / Q000276:immunology*; D010641:Phenotype; D012160:Retina / Q000276:immunology* / Q000473:pathology; D012173:Retinitis / Q000276:immunology* / Q000473:pathology; D012177:Retinol-Binding Proteins / Q000235:genetics / Q000276:immunology*; D012720:Severity of Illness Index; D014602:Uvea / Q000276:immunology* / Q000473:pathology; D014605:Uveitis / Q000276:immunology* / Q000473:pathology; D000099214:Retinol-Binding Proteins, Interstitial
chemical_list: D000939:Epitopes; D005136:Eye Proteins; D010446:Peptide Fragments; D012177:Retinol-Binding Proteins; D000099214:Retinol-Binding Proteins, Interstitial
keywords: autoimmunity; chronic inflammation; epitope spreading; retina; uveitis