TIM-4, expressed by medullary macrophages, regulates respiratory tolerance by mediating phagocytosis of antigen-specific T cells

Mucosal Immunol. 2013 May;6(3):580-90. doi: 10.1038/mi.2012.100. Epub 2012 Nov 14.

Abstract

Respiratory exposure to antigen induces T cell tolerance via several overlapping mechanisms that limit the immune response. While the mechanisms involved in the development of Treg cells have received much attention, those that result in T cell deletion are largely unknown. Herein, we show that F4/80(+) lymph node medullary macrophages expressing TIM-4, a phosphatidylserine receptor, remove antigen-specific T cells during respiratory tolerance, thereby reducing secondary T cell responses. Blockade of TIM-4 inhibited the phagocytosis of antigen-specific T cells by TIM-4 expressing lymph node medullary macrophages, resulting in an increase in the number of antigen-specific T cells and the abrogation of respiratory tolerance. Moreover, specific depletion of medullary macrophages inhibited the induction of respiratory tolerance, highlighting the key role of TIM-4 and medullary macrophages in tolerance. Therefore, TIM-4-mediated clearance of antigen specific T cells represents an important previously unrecognized mechanism regulating respiratory tolerance.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Intranasal
  • Adoptive Transfer
  • Animals
  • Antibodies, Blocking / administration & dosage
  • Antigens / immunology
  • Antigens, Differentiation / metabolism
  • Cells, Cultured
  • Immune Tolerance*
  • Lymph Nodes / pathology
  • Macrophages / immunology*
  • Membrane Proteins / immunology
  • Membrane Proteins / metabolism*
  • Mice
  • Mice, Inbred BALB C
  • Ovalbumin / immunology
  • Phagocytosis / immunology
  • Respiratory Hypersensitivity / immunology*
  • T-Lymphocytes / immunology*

Substances

  • Antibodies, Blocking
  • Antigens
  • Antigens, Differentiation
  • Membrane Proteins
  • TIM-4 protein, mouse
  • monocyte-macrophage differentiation antigen
  • Ovalbumin