title: Human autoantibodies modulate the T cell epitope repertoire but fail to unmask a pathogenic cryptic epitope.
abstract: Abs can tune the responses of Ag-specific T cells by influencing the nature of the epitope repertoire displayed by APCs. We explored the interaction between human self-reactive T cells and human monoclonal autoantibodies from combinatorial Ig-gene libraries derived from autoimmune thyroiditis patients and specific for the main autoantigen thyroid peroxidase (TPO). All human mAbs extensively influenced the T cell epitope repertoire recognized by different TPO-specific T cell clones. The action of the human mAbs was complex, because sometimes the same Ab suppressed or enhanced the epitopes recognized by the 10 different TPO-specific T cell clones. The human mAbs could modulate the epitope repertoire when TPO was added exogenously and when expressed constitutively on the surface of APCs. However, they could not unmask an immunodominant cryptic TPO epitope. In this study, we show that human autoantibodies influence the activity of self-reactive T cells and prove their relevance in concealing or exposing epitopes recognized by self-reactive T cells. However, our results further stress the biological significance of the immunodominant cryptic epitope we have defined and its potential importance in the evolution of autoimmunity.
authors.affiliation: Cancer Sciences Division, Southampton General Hospital, University of Southampton, Tremona Road, Southampton SO16 6YD, United Kingdom. sq@soton.ac.uk
authors.forename: Sonia
authors.initials: S
authors.lastname: Quaratino
authors.forename: Jean
authors.initials: J
authors.lastname: Ruf
authors.forename: Mohamed
authors.initials: M
authors.lastname: Osman
authors.forename: Jin
authors.initials: J
authors.lastname: Guo
authors.forename: Sandra
authors.initials: S
authors.lastname: McLachlan
authors.forename: Basil
authors.initials: B
authors.lastname: Rapoport
authors.forename: Marco
authors.initials: M
authors.lastname: Londei
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D017951:Antigen Presentation / Q000276:immunology; D000938:Antigen-Presenting Cells / Q000276:immunology; D001323:Autoantibodies / Q000276:immunology*; D002999:Clone Cells; D018604:Epitope Mapping; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D015723:Gene Library; D006801:Humans; D007453:Iodide Peroxidase / Q000235:genetics / Q000276:immunology*; D051379:Mice; D013967:Thyroiditis, Autoimmune / Q000235:genetics / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D001323:Autoantibodies; D018984:Epitopes, T-Lymphocyte; D007453:Iodide Peroxidase