Prolongation of rat renal allograft survival by CD4⁺CD25⁻ T cells induced by recipient dendritic cells transfected with IKK2dn.

Previous studies have demonstrated that recipient-derived immature dendritic cells transfected by recombinant adenovirus-mediated IKK2dn (Adv‑IKK2dn) and loaded with donor splenocyte lysate generate CD4+CD25- T cells (Adv-IKK2dn-CD4+CD25- T cells). These cells may inhibit T cell responses in vitro. In the present study, Lewis (LW) rats were administered with an intravenous injection of naive CD4+ T cells, empty adenovirus (Adv-0)-dendritic cell-generated CD4+CD25- T cells (Adv-0-CD4+CD25- T cells), Adv-IKK2dn-CD4+CD25- T cells or an equal volume of normal saline, seven days prior to transplantation. The potency and the mechanism of action of Adv-IKK2dn-CD4+CD25- T cells was analyzed, as well as an investigation of their tolerogenic properties in vivo. Administration of Adv-IKK2dn-CD4+CD25- T cells in vivo to LW rats was observed to markedly prolong the survival of a kidney allograft from Brown Norway rats. Furthermore, the Adv-IKK2dn-CD4+CD25- T cell-treated group exhibited significantly reduced levels of interleukin (Il)-2 and interferon-γ production and increased Il-10 and transforming growth factor-β (TGF-β) secretion. The serum creatinine levels remained at low levels in the Adv-IKK2dn-CD4+CD25- T cell-treated group. Their ability to induce allogeneic T cell proliferation was markedly reduced compared with the other groups. These observations indicated that Adv-IKK2dn-CD4+CD25- T cells induce prolongation of kidney allograft survival in vivo, which is hypothesized to be due to the high expression levels of Il-10 and TGF-β.