RESUMO
PURPOSE: Hematopoietic stem cells from umbilical cord blood are one of the useful resources for stem cell transplantation in the various adult and childhood diseases. Immunologic complications of transplantation, e.g., graft-vs-host disease, occur much less with transplantation of cord blood stem cells. Cord blood-derived dendritic cells (CB-DCs) are known to be different from adult peripheral blood-derived dendritic cells (PB-DCs) in immunologic characteristics. These phenomena might be related to the characteristics of hematopoietic cells in cord blood. Therefore, we analysed characteristics of dendritic cells, which are well-known immune-provoking cells, derived from cord blood precursors. METHODS: Dendritic cells were differentiated from plastic-adherent cord blood monocytes in the presence of GM-CSF and IL-4. Immunophenotype was analysed by flow cytometry and expression of IDO (indoleamine 2, 3-dioxygenase), an enzyme expressed in immune-regulating or tolerogenic DCs, IL-12, IL-10 and IL-6 was measured by RT-PCR along in vitro differentiation. Changes in expression of cytokines and IDO after antibody engagement were also analysed. RESULTS: CB-DCs were very similar to PB-DCs in immunophenotype and expression of cytokines. But CB-DCs expressed IDO transcripts much earlier than PB-DCs during differentiation from precursors. Engagement of CB-DCs with DU-1 mAb induced upregulation of IDO and downregulation of IL-6. CONCLUSION: Although immunophenotype and cytokine expression pattern of CB-DCs were quite similar to those of PB-DCs, CB-DCs expressed IDO earlier than PB-DCs. This might be related to the phenomena that CB-DCs are less immunogenic or, sometimes, tolerance-inducing.