An Autoantigen-Specific, Highly Restricted T Cell Repertoire Infiltrates the Arthritic Joints of Mice in an HLA-DR1 Humanized Mouse Model of Autoimmune Arthritis

Although it is clear that CD4+ T cells play a major role in mediating the pathogenesis of autoimmunity, they often represent only a minor population at the site of inflammation in autoimmune diseases. To investigate the migration and specificity of autoimmune T cells to the inflammatory site, we used the collagen-induced arthritis model to determine the frequency, clonotype, and specificity of T cells that infiltrate arthritic joints. We demonstrate that despite the fact that CD4+ T cells are a minor population of the synovial infiltrate, the CD4+ T cells present are a highly selective subset of the TCR repertoire and, based on CDR3 length polymorphisms, have a limited clonality. Although a similar repertoire of type II collagen (CII)-specific TCR-BV8 and BV14-expressing T cells was found in peripheral lymphoid organs, the clonality of the TCR-BV8 and BV14 T cells that migrate to the arthritic joint generally made up a single CDR3 length. T cell hybridomas produced from these joint-derived cells revealed that many of these infiltrating T cells are CII specific, and the majority recognize mouse CII. These data suggest that despite being a minor population at the site of inflammation, autoantigen-specific T cells are selectively recruited and/or retained in the arthritic joint and may be playing a significant role in the pathogenesis of the autoimmune arthritis. In addition, this model may be very useful for studying the function in situ and the mechanism by which autoimmune T cells are recruited to the site of inflammation.