Functional differences between dendritic cells derived from CD34(+) bone marrow and peripheral blood stem cells

Background and Objectives. It has been previously demonstrated that dendrit ic cells (DCs) are characterized by an Immature stage with high antigen int ernalization capacity, followed by a mature stage with predominantly immuno stimulatory ability. The shift from the Immature to the mature state can be induced In vitro by the addition of tumor necrosis factor-alpha (TNF alpha ). The aim of our study was to investigate the maturation steps of DCs obta ined from cells from peripheral blood stem cells land bone marrow (BM). Design and Methods. DCs were generated in vitro from PBSC and BM CD34(+) se lected cells. The endocytic activity of the cells was measured by means dex tran-FITC uptake and alloreactivity evaluated with mixed leukocyte reaction s. Immunophenotypic analysis was performed by Row cytometry. Results. We observed that DCs from PBSC, to contrast the BM derived DCs, we re never able to up soluble antigens. Mixed leukocyte reactions (MLR) perfo rmed both on PBSC and BM CD34(+) derived DCs showed an allo-stimulatory act ivity comparable to normal controls at day 10, but significantly higher at day 14 after the addition of TNF alpha. Immunophenotypic analysis showed ty pical dendritic markers in all the samples and, after treatment with TNF al pha, enhanced expression of costimulatory molecules. Interpretation and Conclusions. Our data seem to indicate that, in our cult ure conditions. BM-derived DCs could be efficiently used for pulsing with s pecific peptides, while PBSC-derived DCs, being functionally mature, should be more suitable for gene therapy. (C) 2000, Ferrata Storti Foundation.