Amplification of Functional Myeloid-derived Suppressor Cells during Stem Cell Mobilization Induced by Granulocyte Colony-stimulation-factor

The effects of granulocyte colony-stimulation-factor （G-CSF） on stem cell mobilization and its impact on the amplification of myeloid-derived suppressor cells （MDSCs） of donor mice were ex- amined. A mouse model of stem cell mobilization was established by consecutive subcutaneous injec- tion of 100 μg/kg G-CSF for 5 days. The blood from the donor mice was routinely examined during mobilization. Stem cells and MDSCs were analyzed by flow cytometry. The immunosuppressive mole- cules derived from MDSCs in serum and spleen, including hydrogen dioxide （H202） and nitric oxide （NO）, and the activity of nitric oxide synthase （NOS） were determined during the mobilization. Apop- tosis of T lymphocytes was assessed by using Annexin-V/PI. During stem cell mobilization, the number of lymphocytes and white blood cells in the peripheral blood was increased, and peaked on the 4th day. The number of stem cells in G-CSF-treated mice was significantly greater than that in controls （P〈0.01）. The expansions of MSDCs were also observed after G-CSF mobilization, with a more notable rate of growth in the peripheral blood than in the spleen. The activity of NOS and the production of NO were increased in the donor mice, and the serum H202 levels were approximately 4-fold greater than the con- trois. Consequently, apoptosis of T lymphocytes was increased and showed a positive correlation with the elevated percentage of MDSCs. It was concluded that G-CSF could provide sufficient peripheral blood stem cells for transplantation. Exogenous administration of G-CSF caused the accumulation of MDSCs in the peripheral blood and the spleen, which could lead to apoptosis ofT lymphocytes and may offer a new strategy for the prevention and treatment of graft versus host disease.

Reversing effects of traditional Chinese antitumor medicines on colorectal tumor immunosuppression of natural killer cell and T lymphocyte in vitro

Objective： Reversing effects of traditional Chinese medicines on colorectal tumor immunosuppressions of natural killer （NK） cell and T lymphocyte were analyzed to provide evidence on selecting medicines for patients according to the differ- ent types of tumor immunosuppression. Methods： Six traditional Chinese medicines, including Arsenious acid （AS）, Ligustra- zine hydrochloride （LHC）, Astragalus mongholicus bge （AMB）, Matrine N-oxide （MOX）, Polyporus umbellatus polysaccharide （PUPS） and Artesunate （ART）, were enrolled. The reversing effects on suppression of murine splenocyte transformation and NK killing activity were measured by 3-{4,5-dimethyl-2-thiazolyl}-2,5-diphenyl tetrazolium （MTT）, and the effects on the suppressed expression of intefieukin 2 receptor a （IL-2R（I）, CD3E＊~,＊ and CD3~.-~＊ were detected by flow cytometry （FCM）. The effects on immunosuppressive molecules were measured by enzyme linked immunosorbent assay （ELISA）, including transforming growth factor ~1 （TGF-~I）, vascular endothelial growth factor （VEGF）, interleukin 4 （IL-4）, IL-6, IL-10 and pros- taglandin （PG） E2. Results： （1） The reversing effects of AMB on the inhibition of NK killing and CD3 expression were the most significant; the effect of LHC on inhibition of CD3 expression was the strongest; the effects of AMB, PUPS and ART on inhibition of transformation were the greatest; and the effect of ART on inhibition of IL-2Ra expression was the strongest. （2） The correlated molecules of these medicines that exerted reversing effects on colorectal tumor immunosuppression were TGF-~I and IL-10. AMB had the highest down-regulating effect on the secretion of TGF-~I. AS and ART had the highest effects on IL-10. Conclusion： Reversing tumor immunosuppression through the down-regulation of immunosuppressive molecules is one of the novel antitumor mechanisms of traditional Chinese medicines. The clinical use of compounded prescriptions of ART combined with AMB and LHC should be considered to avoid the reduced treatment efficiency caused by tumor im- munosuppression.