Replicative response, immunophenotype, and functional activity of monocyte-derived versus CD34(+)-derived dendritic cells following exposure to various expansion and maturational stimuli

Dendritic cells (DCs), generated ex vivo from blood mononuclear cells (PBMC ) or CD34(+) stem cells, are being used to develop novel immunotherapies. T o establish optimal DC generation, a direct comparison of the optimal cell source, culture conditions, and maturation stimuli was performed, utilizing phenotypic and functional assays as end points. Plastic adherent monocytes from PBMC were expanded in a serum-free medium (X-Vivo 10) for 7 days usin g GM-CSF/IL-4; CD34+ cells were expanded for 14 days using GM-CSF/IL-4/Flt3 L, in either X-Vivo 10 alone or with albumin or autologous plasma. Expanded DC from both cell sources were matured for 7 days with CD40L or IFN-alpha /TNF-alpha. Starting from 2 x 10(7) monocytes, the optimal expansion/matura tion process yielded 1.73 +/- 0.52 x 10(6) CD86(+) DC. Optimal expansion of CD34(+) cells (83.9 +/- 25.0-fold) was achieved using X-Vivo 10 with 5% pl asma, matured with CD40L, and yielded 10.68 +/- 2.72 x 10(6) CD86(+) DC fro m 1 x 10(6) CD34(+) cells. Mature DC from PBMC or CD34(+) cells had similar enhanced expression of MHC class II HLA-DR, CD80, CD83, and CD86 and were potent stimulators of mixed lymphocyte reactions. Prior to maturation, all groups of DC actively phagocytosed apoptotic melanoma cells (approximately 50% of HLA-DR+). CD34(+) DC matured with CD40L or IFN-alpha /TNF-alpha had reduced phagocytic capability (34 and 31% of HLA-DR+ DC, respectively). Sim ilar expansion and functional activity was found using cryopreserved DC pre cursors, cultured in gas permeable bags. We conclude that both cell lineage s produce potent mature DC, permitting exploration of the optimal clinical strategy to trigger anti-tumor immune responses in patients with malignanci es. (C) 2000 Academic Press.