Detection of an autoreactive T-cell population within the polyclonal repertoire that undergoes distinct autoimmune regulator (Aire)-mediated selection.

The autoimmune regulator (Aire) plays a critical role in central tolerance by promoting the display of tissue-specific antigens in the thymus. To study the influence of Aire on thymic selection in a physiological setting, we used tetramer reagents to detect autoreactive T cells specific for the Aire-dependent tissue-specific antigen interphotoreceptor retinoid-binding protein (IRBP), in the polyclonal repertoire. Two class II tetramer reagents were designed to identify T cells specific for two different peptide epitopes of IRBP.

Defective autoimmune regulator-dependent central tolerance to myelin protein zero is linked to autoimmune peripheral neuropathy.

Chronic inflammatory demyelinating polyneuropathy is a debilitating autoimmune disease characterized by peripheral nerve demyelination and dysfunction. How the autoimmune response is initiated, identity of provoking Ags, and pathogenic effector mechanisms are not well defined. The autoimmune regulator (Aire) plays a critical role in central tolerance by promoting thymic expression of self-Ags and deletion of self-reactive T cells.

An autoimmune response to odorant binding protein 1a is associated with dry eye in the Aire-deficient mouse.

Sjögren's Syndrome (SS) is a human autoimmune disease characterized by immune-mediated destruction of the lacrimal and salivary glands. In this study, we show that the Aire-deficient mouse represents a new tool to investigate autoimmune dacryoadenitis and keratoconjunctivitis sicca, features of SS. Previous work in the Aire-deficient mouse suggested a role for alpha-fodrin, a ubiquitous Ag, in the disease process.

A novel myelin P0-specific T cell receptor transgenic mouse develops a fulminant autoimmune peripheral neuropathy.

Autoimmune-prone nonobese diabetic mice deficient for B7-2 spontaneously develop an autoimmune peripheral neuropathy mediated by inflammatory CD4(+) T cells that is reminiscent of Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy. To determine the etiology of this disease, CD4(+) T cell hybridomas were generated from inflamed tissue-derived CD4(+) T cells. A majority of T cell hybridomas were specific for myelin protein 0 (P0), which was the principal target of autoantibody responses targeting nerve proteins.

Effector mechanisms of the autoimmune syndrome in the murine model of autoimmune polyglandular syndrome type 1.

Mutations in the Aire gene result in a clinical phenomenon known as Autoimmune Polyglandular Syndrome (APS) Type I, which classically manifests as a triad of adrenal insufficiency, hypoparathyroidism, and chronic mucocutaneous infections. In addition to this triad, a number of other autoimmune diseases have been observed in APS1 patients including Sjögren's syndrome, vitiligo, alopecia, uveitis, and others. Aire-deficient mice, the animal model for APS1, have highlighted the role of the thymus in the disease process and demonstrated a failure in central tolerance in aire-deficient mice.

Deletional tolerance mediated by extrathymic Aire-expressing cells.

The prevention of autoimmunity requires the elimination of self-reactive T cells during their development and maturation. The expression of diverse self-antigens by stromal cells in the thymus is essential to this process and depends, in part, on the activity of the autoimmune regulator (Aire) gene. Here we report the identification of extrathymic Aire-expressing cells (eTACs) resident within the secondary lymphoid organs.

Mechanisms of an autoimmunity syndrome in mice caused by a dominant mutation in Aire.

Homozygous loss-of-function mutations in AIRE cause autoimmune polyglandular syndrome type 1 (APS 1), which manifests in a classic triad of hypoparathyroidism, adrenal insufficiency, and candidiasis. Interestingly, a kindred with a specific G228W AIRE variant presented with an autosomal dominant autoimmune phenotype distinct from APS 1. We utilized a novel G228W-knockin mouse model to show that this variant acted in a dominant-negative manner to cause a unique autoimmunity syndrome.

Lessons on immune tolerance from the monogenic disease APS1.

Autoimmunity is a complex disease process that results from a breakdown in the ability of the immune system to discriminate self from non-self. One approach to unraveling how autoimmunity occurs is to study monogenic diseases, for which a single gene defect is responsible. Recent work on the monogenic autoimmune disease 'autoimmune polyglandular syndrome type 1' (APS1) and on the causal gene of this disorder--autoimmune regulator (AIRE)--is providing new lessons on how immune tolerance is maintained.

A suppressive oligodeoxynucleotide enhances the efficacy of myelin cocktail/IL-4-tolerizing DNA vaccination and treats autoimmune disease.

Targeting pathogenic T cells with Ag-specific tolerizing DNA vaccines encoding autoantigens is a powerful and feasible therapeutic strategy for Th1-mediated autoimmune diseases. However, plasmid DNA contains abundant unmethylated CpG motifs, which induce a strong Th1 immune response. We describe here a novel approach to counteract this undesired side effect of plasmid DNA used for vaccination in Th1-mediated autoimmune diseases.

Multiple elements of the allergic arm of the immune response modulate autoimmune demyelination.

Analysis of mRNA from multiple sclerosis lesions revealed increased amounts of transcripts for several genes encoding molecules traditionally associated with allergic responses, including prostaglandin D synthase, histamine receptor type 1 (H1R), platelet activating factor receptor, Ig Fc epsilon receptor 1 (Fc epsilon RI), and tryptase. We now demonstrate that, in the animal model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE), mediated by T helper 1 (Th1) T cells, histamine receptor 1 and 2 (H1R and H2R) are present on inflammatory cells in brain lesions. Th1 cells reactive to myelin proteolipid protein expressed more H1R and less H2R than Th2 cells.

Analysis of neuronal gene expression with laser capture microdissection.

The brain is a heterogeneous tissue in which the numbers of neurons, glia, and other cell types vary among anatomic regions. Gene expression studies performed on brain homogenates yield results reflecting mRNA abundance in a mixture of cell types. Therefore, a method for quantifying gene expression in individual cell populations would be useful.