Dendritic cells lentivirally engineered to overexpress interleukin-10 inhibit contact hypersensitivity responses, despite their partial activation induced by transduction-associated physical stress

Background Dendritic cells (DCs) constitute an attractive target for immunotherapeutic approaches. Because DCs are largely refractory to transfection with plasmid DNA, several viral transduction protocols were established. The potential side‐effects of lentiviral transduction on the phenotype and activation state of DCs left unstimulated after transduction have not been assessed. There is a need to analyse these parameters as a result of the requirement of using DCs with a low activation state for therapeutic strategies intended to induce tolerance. Methods Lentivirally‐transduced bone marrow (BM)‐derived DCs (LV‐DCs) in comparison with mock‐transduced (Mock‐DCs) and untreated DCs were analysed with regard to the induction of maturation processes on the RNA, protein and functional level. BM‐DCs engineered to overexpress interleukin (IL)‐10 were analysed for therapeutic potential in a mouse model of allergic contact dermatitis. Results Compared with untreated DCs, Mock‐DCs and LV‐DCs displayed an altered gene expression signature. Mock‐DCs induced a stronger T cell proliferative response than untreated DCs. LV‐DCs did not further augment the T cell proliferative response, but induced a slightly different T cell cytokine pattern compared to Mock‐DCs. Accordingly, the gene promoter of the DC maturation marker fascin mediated efficient expression of the model transgene IL‐10 in unstimulated‐transduced BM‐DCs. Nevertheless, IL‐10 overexpressing BM‐DCs exerted tolerogenic activity and efficiently inhibited the contact hypersensitivity response in previously hapten‐sensitized mice. Conclusions Lentiviral transduction of BM‐DCs results in their partial activation. Nevertheless, the transduction of these DCs with a vector encoding the immunomodulatory cytokine IL‐10 rendered them tolerogenic. Thus, lentivirally‐transduced DCs expressing immunomodulatory molecules represent a promising tool for induction of tolerance. Copyright © 2010 John Wiley & Sons, Ltd.