Effects of tumor necrosis factor-alpha on the morphology of dendritic cells

Objective: To study the effect of tumor necrosis factor-alpha (TNF-alpha) on the morphology and ultrastructure of dendritic cells (DCs).

Methods: Freshly isolated precursors of DCs were cultured in the medium consisting of RPMI 1640 medium and 10 % inactivated fetal bovine serum. In one experiment, the cells were pretreated by TNF-alpha (200 U/ml) for 4 h, followed by treatment with human granulocyte macrophage colony stimulating factor (rhGM-CSF, 800 U/ml) and interleukin-4 (IL-4, 500 U/ml). The above treatments were repeated again every 48 h. The cells in another experiment were treated with rhGM-CSF (800 U/ml) and IL-4 (500 U/ml) on the day of in vitro culture, which was repeated every 48 h with a treatment with TNF-alpha (200 U/ml) on day 5 of cell culture. On day 8, the cells in the 2 parallel experiments were collected with the former cells designated as T-DC and the latter DC. Morphological differences between the 2 group of cells were observed using light microscope and scanning electron microscope.

Results: The T-DC exhibited more typical dendric processes than DCs did.

Conclusions: Pretreatment of the precursors of DCs with TNF-alpha for 4 h, in comparison with TNF-alpha treatment on day 5 of cell culture, produced DCs with more typical and conspicuous dendric morphologies.