Immunological tolerance to muscle autoantigens involves peripheral deletion of autoreactive CD8+ T cells

PLoS One. 2012;7(5):e36444. doi: 10.1371/journal.pone.0036444. Epub 2012 May 3.

Abstract

Muscle potentially represents the most abundant source of autoantigens of the body and can be targeted by a variety of severe autoimmune diseases. Yet, the mechanisms of immunological tolerance toward muscle autoantigens remain mostly unknown. We investigated this issue in transgenic SM-Ova mice that express an ovalbumin (Ova) neo-autoantigen specifically in skeletal muscle. We previously reported that antigen specific CD4(+) T cell are immunologically ignorant to endogenous Ova in this model but can be stimulated upon immunization. In contrast, Ova-specific CD8(+) T cells were suspected to be either unresponsive to Ova challenge or functionally defective. We now extend our investigations on the mechanisms governing CD8(+) tolerance in SM-Ova mice. We show herein that Ova-specific CD8(+) T cells are not detected upon challenge with strongly immunogenic Ova vaccines even after depletion of regulatory T cells. Ova-specific CD8(+) T cells from OT-I mice adoptively transferred to SM-Ova mice started to proliferate in vivo, acquired CD69 and PD-1 but subsequently down-regulated Bcl-2 and disappeared from the periphery, suggesting a mechanism of peripheral deletion. Peripheral deletion of endogenous Ova-specific cells was formally demonstrated in chimeric SM-Ova mice engrafted with bone marrow cells containing T cell precursors from OT-I TCR-transgenic mice. Thus, the present findings demonstrate that immunological tolerance to muscle autoantigens involves peripheral deletion of autoreactive CD8(+) T cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adoptive Transfer
  • Animals
  • Autoantigens / immunology*
  • Autoimmunity
  • CD8-Positive T-Lymphocytes / immunology*
  • Immune Tolerance*
  • Lymph Nodes / immunology
  • Lymphocyte Depletion
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Muscles / immunology*
  • T-Lymphocytes, Regulatory / immunology
  • Thymectomy
  • Transplantation Chimera

Substances

  • Autoantigens