Direct presentation of a melanocyte-associated antigen in peripheral lymph nodes induces cytotoxic CD8+ T cells

Cancer Res. 2008 Oct 15;68(20):8410-8. doi: 10.1158/0008-5472.CAN-08-0809.

Abstract

Encounter of self-antigens in the periphery by mature T cells induces tolerance in the steady-state. Hence, it is not understood why the same peripheral antigens are also promiscuously expressed in the thymus to mediate central tolerance. Here, we analyzed CD8(+) T-cell tolerance to such an antigen constituted by ovalbumin under the control of the tyrosinase promoter. As expected, endogenous CD8(+) T-cell responses were altered in the periphery of transgenic mice, resulting from promiscuous expression of the self-antigen in mature medullary epithelial cells and deletion of high-affinity T cells in the thymus. In adoptive T-cell transfer experiments, we observed constitutive presentation of the self-antigen in peripheral lymph nodes. Notably, this self-antigen presentation induced persisting cytotoxic cells from high-affinity CD8(+) T-cell precursors. Lymph node resident melanoblasts expressing tyrosinase directly presented the self-antigen to CD8(+) T cells, independently of bone marrow-derived antigen-presenting cells. This peripheral priming was independent of the subcellular localization of the self-antigen, indicating that this mechanism may apply to other melanocyte-associated antigens. Hence, central tolerance by promiscuous expression of peripheral antigens is a mandatory, rather than a superfluous, mechanism to counteract the peripheral priming, at least for self-antigens that can be directly presented in lymph nodes. The peripheral priming by lymph node melanoblasts identified here may constitute an advantage for immunotherapies based on adoptive T-cell transfer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigen Presentation*
  • Autoantigens / immunology*
  • Immunotherapy
  • Lymph Nodes / immunology*
  • Melanocytes / immunology*
  • Melanoma / therapy
  • Mice
  • Mice, Inbred C57BL
  • Mice, Inbred DBA
  • Ovalbumin / genetics
  • Ovalbumin / immunology
  • T-Lymphocytes, Cytotoxic / immunology*

Substances

  • Autoantigens
  • Ovalbumin