#47
HUMAN DENDRITIC CELLS TREATED WITH INHIBITORS OF NFκB ABROGATE RESPONSES TO ALLOANTIGEN.
A. Hernandez, PhD, W. A. Ross, MD, B. B. Blomberg, PhD, M. Burger, J. M. Mathew, PhD, A. Tzakis, MD, J. Miller, MD and V. Esquenazi, PhD. U. Dept. of Surgery; Dept. of Microb.
Immuno and Miami FL, USA, U. of Miami School of Medicine, 33136, VA Medical Center.
Dendritic cells (DC) prime T cells (Tc) but can also tolerize Tc and abrogate the immune response. Studies have shown that blocking NF-kB during DC differentiation promotes allograft survival in mice. The aim is to assess the effect of blocking NF-kB in human DC on Tc allostimulation and generation of regulatory cell populations. CD34+ BMC were incubated with PMA to produce DC (BMC-DC) in the presence (treated) or absence (untreated) of BAY11-7082 or ASA, both inhibitors of NF-kB. Treated or untreated CD14+ PBMC were incubated with cytokines to promote differentiation/maturation into DC (PBMC-DC). Mismatched allogeneic purified Tc were cocultured with either (1)irradiated (IRR) BMC-DC (treated or untreated) (2)IRR PBMC-DC (treated or untreated) and Tc proliferation was measured. Tc were then isolated from these 1° cultures and used in a 2nd proliferation assay where they were combined with freshly isolated Tc from the same donor and cultured with allo (or third party) PBMC. Treated DC were far less potent than untreated DC in their ability to stimulate Tc proliferation. Treated DC were notably deficient in CD40. Cells in the treated cocultures produced more IL-10 and less IFN-γ. Cultures with fresh Tc + Tc isolated from cocultures with treated DC proliferated less in response to allo and third party stimulation versus cultures with fresh Tc + Tc isolated from cocultures with control DC. These experiments show that human DC treated with inhibitors of NF-kB may facilitate induction of tolerance in organ transplantation. DC lacking costimulatory molecules (ie.CD40) may cause responding Tc to become suppressors or render them anergic.