Neutralizing IL-7 promotes long-term allograft survival induced by CD40/CD40L costimulatory blockade

Am J Transplant. 2006 Dec;6(12):2851-60. doi: 10.1111/j.1600-6143.2006.01550.x.

Abstract

Memory T cells are somewhat resistant to immunosuppresion. They therefore pose a threat to inducing long-term allograft survival. IL-7 is essential for memory T-cell generation. Here, we investigated whether neutralizing IL-7 promotes allograft survival. We found that neutralizing IL-7 alone did not significantly prolong allograft survival. However, blocking both IL-7 and CD154 signaling synergistically prolonged allograft survival. In contrast, neutralizing IL-2 failed to further prolong allograft survival induced by CD40/CD154 costimulatory blockade. Allospecific memory CD8+ T-cell generation was severely impaired under the treatment of anti-IL-7 plus anti-CD154 Ab while administering recombinant IL-7 enhanced CD8+ memory generation even under donor-specific transfusion plus anti-CD154 Ab treatment. Neutralizing IL-7, but not IL-2, together with blocking CD154 synergistically suppressed the proliferation of naïve/effector CD8+ T cells infiltrating grafts. Nevertheless, neutralizing IL-7 did not alter regulatory T-cell generation while neutralizing IL-2 suppressed their generation. Hence, targeting IL-7 represents a new strategy to prolong allograft survival by acting on both naïve and memory T cells. Long-term allograft survival may be achieved by neutralizing IL-7 plus CD40/CD154 blockade, since CD40/CD154 costimulatory blockade prevents acute rejection while neutralizing IL-7 suppresses the generation of memory T cells that persist and mediate late or chronic rejection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CD40 Antigens / antagonists & inhibitors*
  • CD40 Ligand / antagonists & inhibitors*
  • Cell Division
  • Dendritic Cells / cytology
  • Dendritic Cells / immunology
  • Graft Survival / immunology*
  • Heart Transplantation / immunology*
  • Immunologic Memory
  • Immunophenotyping
  • Interleukin-7 / immunology*
  • Lymphocyte Activation
  • Mice
  • Mice, Inbred C57BL
  • Neutralization Tests
  • Peptidyl-Dipeptidase A / metabolism
  • Skin Transplantation / immunology*
  • T-Lymphocytes / immunology
  • Transplantation, Homologous / immunology*

Substances

  • CD40 Antigens
  • Interleukin-7
  • CD40 Ligand
  • Peptidyl-Dipeptidase A