Study of the Effects of Fullerenol C60(OH)24 on Differentiation of Dendritic Cells from Peripheral Blood Monocytes

Abstract Objective: The aim of the present study was to evaluate the influence of fullerenol C60(OH)24 nanoparticles on differentiation of dendritic cells (DCs) from human peripheral blood monocytes in an in vitro system. Materials and methods: Peripheral blood monocytes from healthy donors were induced to a DC phenotype using GM-CSF (100 ng/mL) and IL-4 (20 ng/mL); lipopolysaccharide (LPS) (1 μg/mL) was also added to the cultures. Fullerenol C60(OH)24 nanoparticles were applied at concentrations of 0.25–200 μg/mL; controls contained no nanoparticles. After incubation for 7 days in complete RPMI-1640 medium (сRPMI) at 37°C and 5% CO2, cell viability, expression of CD209 and CD83, nanoparticle uptake by cells (assessed by flow cytometry using the autofluorescence of C60(OH)24), and cell morphology by inverted microscopy were evaluated. Results: Cell viability in cultures treated with 12.5–50 μg/mL fullerenol decreased significantly, on average from 95 to 85%, while at high concentrations (100–200 μg/mL) viability was maintained at approximately 90% on average. The absolute cell count per culture volume significantly decreased at fullerenol concentrations of 25, 50, and 200 μg/mL. Expression of CD209, a marker of DCs, was significantly reduced at 100–200 μg/mL fullerenol, whereas the proportion of CD83+ cells, reflecting DC maturation, decreased starting at 50 μg/mL. The percentage of mature DCs (CD209+CD83+) was significantly reduced at ≥50 μg/mL nanoparticles in culture. It was shown that increasing fullerenol concentration was accompanied by increased nanoparticle uptake by cells, reaching a maximum at 100–200 μg/mL. Morphologically, spindle-shaped cells with dendrites predominated in cultures with 25–50 μg/mL nanoparticles. At concentrations of 100–200 μg/mL, cells remained rounded and lacked dendrites, retaining a monocyte-like appearance. Conclusion: These observations indicate that fullerenol, despite its modest effect on cell viability, decreases the absolute viable cell count in the culture and negatively affects their differentiation into DCs. The study results are relevant for assessment of the immunocompatibility of carbon nanomaterials and their prospects for biomedical application.