IL-7 receptor blockade following T cell depletion promotes long-term allograft survival

J Clin Invest. 2014 Apr;124(4):1723-33. doi: 10.1172/JCI66287. Epub 2014 Feb 24.

Abstract

T cell depletion is commonly used in organ transplantation for immunosuppression; however, a restoration of T cell homeostasis following depletion leads to increased memory T cells, which may promote transplant rejection. The cytokine IL-7 is important for controlling lymphopoiesis under both normal and lymphopenic conditions. Here, we investigated whether blocking IL-7 signaling with a mAb that targets IL-7 receptor α (IL-7Rα) alone or following T cell depletion confers an advantage for allograft survival in murine transplant models. We found that IL-7R blockade alone induced indefinite pancreatic islet allograft survival if anti-IL-7R treatment was started 3 weeks before graft. IL-7R blockade following anti-CD4- and anti-CD8-mediated T cell depletion markedly prolonged skin allograft survival. Furthermore, IL-7 inhibition in combination with T cell depletion synergized with either CTLA-4Ig administration or suboptimal doses of tacrolimus to induce long-term skin graft acceptance in this stringent transplant model. Together, these therapies inhibited T cell reconstitution, decreased memory T cell numbers, increased the relative frequency of Tregs, and abrogated both cellular and humoral alloimmune responses. Our data suggest that IL-7R blockade following T cell depletion has potential as a robust, immunosuppressive therapy in transplantation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abatacept
  • Allografts
  • Animals
  • Antibodies, Monoclonal / administration & dosage
  • Graft Survival / immunology*
  • Immunity, Cellular
  • Immunity, Humoral
  • Immunoconjugates / administration & dosage
  • Immunosuppression Therapy / methods*
  • Immunosuppressive Agents / administration & dosage
  • Islets of Langerhans Transplantation / immunology
  • Lymphocyte Depletion*
  • Male
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Mice, Mutant Strains
  • Mice, Nude
  • Receptors, Interleukin-7 / antagonists & inhibitors*
  • Skin Transplantation
  • T-Lymphocytes / immunology*
  • Tacrolimus / administration & dosage
  • Transplantation Immunology
  • Transplantation Tolerance / immunology

Substances

  • Antibodies, Monoclonal
  • Immunoconjugates
  • Immunosuppressive Agents
  • Receptors, Interleukin-7
  • Abatacept
  • Tacrolimus