Defective selection of thymic regulatory T cells accompanies autoimmunity and pulmonary infiltrates in Tcra-deficient mice double transgenic for human La/Sjögren's syndrome-B and human La-specific TCR

• Published in: The Journal of immunology (1950) Vol. 194; no. 4; pp. 1514 - 1522
• Main Authors: Yaciuk, Jane C, Pan, Yujun, Schwarz, Karen, Pan, Zi-Jian, Maier-Moore, Jacen S, Kosanke, Stanley D, Lawrence, Christina, Farris, A Darise
• Format: Journal Article
• Language: English
• Published: United States 15-02-2015
• Subjects: Animals; Antigen Presentation - immunology; Autoantibodies - immunology; Autoantigens - immunology; Autoimmunity - immunology; Enzyme-Linked Immunosorbent Assay; Epitopes, T-Lymphocyte - immunology; Flow Cytometry; Genes, T-Cell Receptor alpha - immunology; Humans; Immune Tolerance - immunology; Immunohistochemistry; Lung Diseases, Interstitial - immunology; Lymphocyte Activation - immunology; Mice; Mice, Inbred C57BL; Mice, Transgenic; Polymerase Chain Reaction; Receptors, Antigen, T-Cell; Ribonucleoproteins - immunology; Sjogren's Syndrome - complications; Sjogren's Syndrome - immunology; SS-B Antigen; T-Lymphocytes, Regulatory - immunology; Thymus Gland - cytology; Thymus Gland - immunology
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.1400319

A human La/Sjögren's syndrome-B (hLa)-specific TCR/hLa neo-self-Ag double-transgenic (Tg) mouse model was developed and used to investigate cellular tolerance and autoimmunity to the ubiquitous RNA-binding La Ag often targeted in systemic lupus erythematosus and Sjögren's syndrome. Extensive thymic clonal deletion of CD4(+) T cells occurred in H-2(k/k) double-Tg mice presenting high levels of the I-E(k)-restricted hLa T cell epitope. In contrast, deletion was less extensive in H-2(k/b) double-Tg mice presenting lower levels of the epitope, and some surviving thymocytes were positively selected as thymic regulatory T cells (tTreg). These mice remained serologically tolerant to hLa and healthy. H-2(k/b) double-Tg mice deficient of all endogenous Tcra genes, a deficiency known to impair Treg development and function, produced IgG anti-hLa autoantibodies and displayed defective tTreg development. These autoimmune mice had interstitial lung disease characterized by lymphocytic aggregates containing Tg T cells with an activated, effector memory phenotype. Salivary gland infiltrates were notably absent. Thus, expression of nuclear hLa Ag induces thymic clonal deletion and tTreg selection, and lymphocytic infiltration of the lung is a consequence of La-specific CD4(+) T cell autoimmunity.