Inhibition of recall responses through complementary therapies targeting CD8+ T-cell- and alloantibody-dependent allocytotoxicity in sensitized transplant recipients

Cell Transplant. 2013;22(7):1157-69. doi: 10.3727/096368912X657350. Epub 2012 Oct 11.

Abstract

Allospecific T memory cell responses in transplant recipients arise from environmental exposure to previous transplantation or cross-reactive heterologous immunity. Unfortunately, these memory responses pose a significant barrier to the survival of transplanted tissue. We have previously reported that concurrent inhibition of CD154 and LFA-1 suppresses primary CD8-dependent rejection responses that are not controlled by conventional immunosuppressive strategies. We hypothesized that CD154- and LFA-1-mediated inhibition, by targeting activation as well as effector functions, may also be efficacious for the control of alloreactive CD8+ T-cell responses in sensitized hosts. We found that treatment with anti-LFA-1 mAb alone enhanced transplant survival and reduced CD8-mediated cytotoxicity in sensitized CD4 KO recipients. However, treatment with anti-CD154 mAb alone did not have an effect. Notably, when both CD4- and CD8-dependent rejection pathways are operative (wild-type sensitized recipients), LFA-1 significantly inhibited CD8-mediated in vivo allocytotoxicity but did not correspond with enhanced hepatocyte survival. We hypothesized that this was due to alloantibody-mediated rejection. When anti-LFA-1 mAb treatment was combined with macrophage depletion, which we have previously reported impairs alloantibody-mediated parenchymal cell damage, in vivo cytotoxic effector function was significantly decreased and was accompanied by significant enhancement of hepatocyte survival in sensitized wild-type recipients. Therefore, LFA-1 is a potent therapeutic target for reduction of CD8-mediated cytotoxicity in sensitized transplant recipients and can be combined with other treatments that target non-CD8-mediated recall alloimmunity.

Publication types

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

MeSH terms

  • Animals
  • Antibodies, Monoclonal / immunology
  • Antibodies, Monoclonal / pharmacology
  • CD4 Antigens / genetics
  • CD4 Antigens / metabolism
  • CD40 Ligand / immunology
  • CD8-Positive T-Lymphocytes / drug effects
  • CD8-Positive T-Lymphocytes / immunology*
  • Graft Rejection / immunology
  • Graft Survival / immunology
  • Hepatocytes / cytology
  • Hepatocytes / transplantation
  • Immunotherapy
  • Isoantibodies / immunology*
  • Isoantibodies / pharmacology
  • Liver / physiology
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Transplantation, Homologous

Substances

  • Antibodies, Monoclonal
  • CD4 Antigens
  • Isoantibodies
  • anti-LFA-1 monoclonal antibody
  • CD40 Ligand