Tehran University Medical Journal

Background: Nowadays, dendritic cells (DCs) have a special place in cancer treatment strategies and they have been used for tumor immunotherapy as they can induce immune response against tumor cells. Researchers have been trying to generate efficient dendritic cells in vitro therefore, this research was done to generate them for use in research and tumor immunotherapy.

Methods: This study took place at Urmia University in 2010-2011 years. In this study plastic adherent monocytes were incubated with granulocyte-macrophage colony stimulating factor (GM-CSF) and interleukin-4 (IL-4) for five days. Finally, fully matured and stable DCs were generated by 48 hours of incubation in a monocyte conditioned medium (MCM) containing tumor necrosis factor-α (TNF-α) and epithelial cells. Phenotypic and functional analysis were carried out by using anti-CD14, anti-CD80, anti-CD86, and anti-CD83 monoclonal antibodies, and by determining their phagocytic activity, mixed lymphocyte reaction (MLR) and cytokine production, respectively.

Results: Dendritic cells were produced with high levels of surface molecule, i.e. of CD80, CD83, CD86, HLA-DR, expression and low levels of CD14 expression. Dendritic cells showed efficient phagocytosis and ability to stimulate T-lymphocytes. Moreover, dendritic cells could secrete high levels of interleukin-12 (IL-12) cytokine which was depictive of their full maturation. Measurement of the produced cytokines showed the generation of type-1 dendritic cells (DC1).

Conclusion: Our study showed that skin epithelial cells could induce maturation of monocyte-derived dendritic cells (DCs). This feeder layer led to the production of efficient dendritic cells with the ability to be used for tumor immunotherapy.

Background: Hydroxyapatite nanoparticles have a more surface contact and solubility than conventional hydroxyapatite. Hydroxynanoparticles enhances the biological and mechanical properties of new regenerated tissues. The hydroxyapatite nanoparticles have received attention as a new and effective osseous graft for using as scaffolds in bone regeneration. The reports on hydroxyapatite nanoparticles biocompatibility are controversial. It has been shown that hydroxyapatite nanoparticles induces inflammatory reaction and apoptosis. The aim of the present study was to evaluate the cytotoxicity of nano-hydroxyapatite on the human epithelial cells.

Methods: The study was experimental and completed in vitro. The study was carried out in department of Immonulogy, Faculty of Medicine, Shahid Beheshti University of Medical Sciences in November 2014. The human-derived oral epithelium cell line (KB) obtained from Pasteur Institute, Tehran, Iran were exposed to hydroxyapatite nanoparticles at 0.01, 0.05, 0.1, 0.5, 0.75, 1, 2.5 and 5 mg/ml concentrations in 24, 48 and 72 hours. Rod-shaped hydroxyapatite nanoparticles with 99% purity and maximum 100 nm sized particles were used. Methylthiazol tetrazolium bromide (MTT) method was employed for cell vitality evaluation. Enzyme-linked immunosorbent assay (ELISA) was used for assessing the viability of cells. Distilled water and fetal bovine serum (FBS) were positive and negative controls. ANOVA and Duncan tests were used for statistical analysis.

Results: The cytotoxicity of different concentrations of hydroxyapatite nanoparticles on human-derived oral epithelium cell line in 24 (P< 0.001), 48 (P< 0.001) and 72 hours (P< 0.001) was significantly different. The nano-hydroxyapatite particles at 0.5 to 1 mg/ml had the highest cytotoxicity effect on human-derived oral epithelium cells in 24, 48 and 72 hours. Lower concentrations than 0.05 mg/ml had the best biocompatibility properties in 24, 48 and 72 hours.

Conclusion: Hydroxyapatite nanoparticles had a good biocompatibility. The biocompatibility of hydroxyapatite nanoparticles were dose and time dependent. The lower concentrations than 0.05 mg/ml of nano-hydroxyapatite had the best biocompatibility over time.