[Effects of vascular endothelial growth factor on differentiation and function of dendritic cells generated from CD34+ hematopoietic progenitor cells in vitro].

OBJECTIVE: To investigate the effects of vascular endothelial growth factor (VEGF) on differentiation and function of dendritic cells derived from CD34+ hematopoietic progenitor cells. METHODS: After isolation from umbilical cord blood with a high-gradient magnetic cell sorting system (MACS), the CD34+ cells were cultured with a cocktail cytokines for differentiating into dendritic cells (DC). The cells were stimulated by VEGF (25 ng/ml) either at the beginning or at day 9 of culture. Kinetics analysis of cell proliferation was performed during the process of cell culture, and the expression of DC differentiation antigens including CD1alpha, CD83, CD80, CD54 and HLA-DR was examined by flow cytometry. DC function was evaluated by the ability to induce proliferation of allogeneic T cells in mixed lymphocyte reaction (MLR) assay, and the production of IL-12 by ELISA. RESULTS: VEGF added at day 1 of culture induced an increase of total cell numbers by (1.51 +/- 0.23)-folds (P = 0.001). VEGF added at the initial but not the late stage of culture could dramatically down-regulate the expression of CD1a [(33.00 +/- 2.12)% vs (81.20 +/- 6.93)%], CD83 [(42.23 +/- 1.15)% vs (87.98 +/- 7.97)%], CD80 (42.93 +/- 1.32)% vs (94.53 +/- 0.87)%], and HLA-DR [(37.93 +/- 5.30)% vs (74.15 +/- 3.74)%], while obviously up-regulate the expression of CD14. Moreover, the inhibitory effect of VEGF on DC function was confirmed by a reduced ability to induce proliferation of allogeneic T cells and production of IL-12 (P < 0.01). CONCLUSIONS: VEGF could induce the expansion of hematopoietic progenitor cells and inhibit at the early stage their differentiation into mature DC.