DnIKK2-transfected dendritic cells induce a novel population of inducible nitric oxide synthase-expressing CD4+CD25- cells with tolerogenic properties

Sistiana Aiello, Paola Cassis, Linda Cassis, Susanna Tomasoni, Ariela Benigni, Anna Pezzotta, Regiane A. Cavinato, Daniela Cugini, Nadia Azzollini, Marilena Mister, Lorena Longaretti, Angus W. Thomson, Giuseppe Remuzzi, Marina Noris

Research output: Contribution to journalArticlepeer-review


BACKGROUND. We previously documented that rat bone marrow-derived dendritic cells (DCs), transfected with an adenovirus encoding a dominant negative form of IKK2 (dnIKK2), have impaired allostimulatory capacity and generate CD4 T cells with regulatory function. Here we investigate the potency, the phenotype, and the mechanism of action of dnIKK2-DC-induced regulatory cells and we evaluated their tolerogenic properties in vivo. METHODS. Brown Norway (BN) transfected dnIKK2-DCs were cultured with Lewis (LW) lymphocytes in primary mixed lymphocyte reaction (MLR). CD4 T cells were purified from primary MLR and incubated in secondary coculture MLR with LW lymphocytes. Phenotypic characterization was performed by fluorescence-activated cell sorting and real-time polymerase chain reaction. The tolerogenic potential of CD4 T cells pre-exposed to dnIKK2-DCs was evaluated in vivo in a model of kidney allotransplantation. RESULTS. CD4 T cells pre-exposed to dnIKK2-DCs were CD4CD25 and expressed interleukin (IL)-10, transforming growth factor-beta, interferon-gamma, IL-2, and inducible nitric oxide synthase (iNOS). These cells (dnIKK2-Treg), cocultured (at up to 1:10 ratio) with a primary MLR, suppressed T-cell proliferation to alloantigens. The regulatory effect was cell-to-cell contact-independent since it was also observed in a transwell system. A nitric oxide synthase inhibitor significantly reverted dnIKK2-Treg-mediated suppression, whereas neutralizing antibodies to IL-10 and TGF-beta had no significant effect. DnIKK2-Treg given in vivo to LW rats prolonged the survival of a kidney allograft from BN rats (the donor rat strain used for generating DCs). CONCLUSIONS. DnIKK2-Treg is a unique population of CD4CD25 T cells expressing high levels of iNOS. These cells potently inhibit T-cell response in vitro and induce prolongation of kidney allograft survival in vivo.

Original languageEnglish
Pages (from-to)474-484
Number of pages11
Issue number4
Publication statusPublished - Feb 2007


  • Dendritic cells
  • Inducible nitric oxide synthase
  • Rat kidney allotransplantation
  • T-regulatory cells

ASJC Scopus subject areas

  • Transplantation
  • Immunology


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