Objective To investigate the effects of hydrocortisone (HC) on proliferation and killing activity of NK cells against pancreatic cancer SW1990 cells in vitro.Methods Peripheral blood mononuclear cells of healthy people were isolated and cultured with NK cells medium containing IL-1S.When the purity of NK cells reached above 70％,different concentrations of HC (10-6,10-5,10-4,10-3 μmol/L) were added and co-cultured with NK cells for 7 days.And NK cells without HC were used as control.CD3-CD56 + NK cell numbers of each group were countered by trypan blue staining.Perforin,granzyme B and IFN-γ expression of CD3-CD56+ + NK cells were verified by flow cytometry.NK cells and SW1990 cells were co-cultured with a 20∶1effector to target ratio,then the cytotoxic activity of NK cells against SW1990 cells were analyzed by CCK-8 kit.Results After treatment with different concentration of HC for 7 days,NK cells purity of each group reached 70.72％ ～ 76.39％,and it was not significantly different with that in control group [(72.61 ± 3.76) ％].The proliferation folds of NK cells treated with 10-6,10-5,10-4,10-3 μmol/L HC were (9.13 ± 0.94),(9.67 ±1.51),(10.33±1.07),(8.40±1.47) times,respectively,while it was (4.23 ±0.82) times in control group (all P ＜0.01).The killing effects of NK cells on SW1990 cells were (58.58 ± 4.89) ％,(62.27 ± 5.63) ％,(64.02 ± 5.79) ％,(63.88 ± 3.61) ％,which were higher than that in control group [(57.46 ± 5.11) ％],moreover,the difference between NK cells of 10-4 μmol/L HC treatment group and control group was statistically significant(P ＜ 0.05).The expressions of perforins of 10-4,10-3 μmol/L HC treatment group were (96.71 ± 3.04) ％,(97.56 ± 2.18) ％,which were significantly higher than that in control group [(92.40 ±3.53)％,P ＜0.05 or 0.01].The expression of granzyme B in 10-5 μmol/L HC treatment group was (78.23 ±2.94)％,which were significantly higher than that in control group [(73.68 ±3.52) ％,P ＜0.05].The expressions of IFN-γ in 10-5,10-4,10-3 μmol/L HC treatment group were (96.61 ±2.04)％,(97.58 ± 2.17)％,(98.00 ± 1.77)％,which were significantly higher than that in control group [(92.44 ± 2.74)％,P＜0.01].Conclusions HC can promote IL-15 activated NK cells proliferation and enhance NK cells mediated killing activity against SW1990 cells with proper concentration,and up-regulation of perforin,granzyme B and IFN-γ expression may be the main mechanisms.

Municipal wastewater is usually problematic for the environment. The process of oleaginous microalgal culture requires large amounts of nutrients and water. Therefore, we studied the feasibility of oleaginous microalgal culture of Scenedesmus dimorphus in bubbled column photobioreactor with municipal wastewater added with different nutrients. S. dimorphus could adapt municipal nutrient-rich wastewater by adding some nutrients as nitrogen, phosphorus, ferric ammonium citrate and trace elements, and the amounts of such nutrients have significant effects on cell growth, biomass yield and lipid accumulation. At optimum compositions of wastewater medium, the algal cell concentration could reach 8.0 g/L, higher than that of 5.0 g/L in standard BG11. Furthermore, S. dimorphus had strong capacity to absorb inorganic nitrogen and phosphorus from its culture water. There was almost no total nitrogen and phosphorus residues in culture medium after three or four days culturing when the adding mounts of nitrate and phosphate in wastewater medium were no more than 185.2 mg/L and 16.1 mg/L respectively under the experimental conditions. As a conclusion, it was feasible to cultivate oleaginous microalgae with municipal nutrient-rich wastewater, not only producing feedstock for algal biodiesel, but also removing inorganic nitrogen and phosphorus from wastewater.
Biofuels ; Cities ; Culture Techniques ; methods ; Lipids ; biosynthesis ; Microalgae ; metabolism ; Photobioreactors ; Scenedesmus ; growth & development ; metabolism ; Waste Disposal, Fluid ; methods ; Waste Products