Nanodiamond and nanoplatinum liquid, DPV576, activates human monocyte-derived dendritic cells in vitro.

Background: The influence of nanoparticles on the immune system is poorly understood. It was recently shown that exposure to a mixture of nanodiamond (ND)- and nanoplatinum (NP)-coated material (DPV576-C) activates murine T-cells. This study examined the role of a dispersed aqueous mixture of ND/NP (DPV576) in activating human dendritic cells (DCs) in vitro.

Methods: Human monocyte-derived DCs were treated with DPV576 at various concentrations (50, 100 and 200 μg/ml) for 24 hours in vitro. Activation of DCs was determined by assessing the expression of co-stimulatory and maturation markers (CD80, CD83, CD86, HLADR), production of cytokines, and induction of proliferation of naïve CD4 T-cells. Expression of co-stimulatory molecules and cell proliferation were analysed by flow cytometry and cytokine secretion by ELISA.

Results: DPV576 treatment of DCs resulted in: (i) increased CD83 and CD86 expression on DCs, (ii) up-regulation in the levels of DC-secreted cytokines IL-6, TNF and IL-10, and (iii) increased ability to induce proliferation in CD4(+) T-cells which is associated with increased expression of T-cell activation marker CD25.

Conclusions: Solution containing ND/NP (DPV576) activated human DCs and DCs-driven CD4 naive T-cell proliferation in vitro, which may be useful in boosting immune responses in cancer treatment.