Medullary thymic epithelial cell depletion leads to autoimmune hepatitis.

ABSTRACT: TRAF6, an E3 ubiquitin protein ligase, plays a critical role in T cell tolerance by regulating medullary thymic epithelial cell (mTEC) development. mTECs regulate T cell tolerance by ectopically expressing self-antigens and eliminating autoreactive T cells in the thymus. Here we show that mice with mTEC depletion due to conditional deletion of Traf6 expression in murine thymic epithelial cells (Traf6?TEC mice) showed a surprisingly narrow spectrum of autoimmunity affecting the liver. The liver inflammation in Traf6?TEC mice exhibited all the histological and immunological characteristics of human autoimmune hepatitis (AIH). The role of T cells in AIH establishment was supported by intrahepatic T cell population changes and AIH development after transfer of liver T cells into immunodeficient mice. Despite a 50% reduction in natural Treg thymic output, peripheral tolerance in Traf6?TEC mice was normal, whereas compensatory T regulatory mechanisms were evident in the liver of these animals. These data indicate that mTECs exert a cell-autonomous role in central T cell tolerance and organ-specific autoimmunity, but play a redundant role in peripheral tolerance. These findings also demonstrate that Traf6?TEC mice are a relevant model with which to study the pathophysiology of AIH, as well as autoantigen-specific T cell responses and regulatory mechanisms underlying this disease.

SUBMITTER: Bonito AJ 

PROVIDER: S-EPMC3726151 | biostudies-literature | 2013 Aug

REPOSITORIES: biostudies-literature