ABSTRACT
AIM: To study the effects of recombinant soluble MHC class Ⅰ chain-related protein A (sMICA) on the cytotoxicity, secretion of IFN-γ, proliferation and apoptosis of peripheral NK cells. METHODS: After NK cells were cocultured with recombinant soluble MICA proteins overnight, the cytotoxicity of NK cell on target cells was detected by flow cytometry. The supemant was collected to determine the concentration of IFN-γ by ELISA. The proliferation of NK cells to sMICA was detected by MTS/PMS. NK cells were labeled with annexin V and PI to analyze their apoptosis. RESULTS: Soluble MICA inhibited the cytotoxicity of NK cells and down-regulated the secretion of IFN-γ, but it showed no effects on the proliferation and apoptosis of freshly isolated peripheral NK cells. CONCLUSION: The soluble MICA shedding from tumor cells could be a pathway of cancer immune evasion by down-regulating the biologic activities of NK cells.
ABSTRACT
Objective To study the influence of recipient tolerogenic dendritic cells(DCs) loaded with donor renal antigen on renal allografts survival in rats.Methods Bone marrow derived DCs of Lewis rats were loaded with antigens from donor kidney of BN rats and transferred with AdvCTLA-4Ig to generate tolerogenic DCs.The tolerogenic DCs were injected into the Lewis recipient 24 h before BN→Lewis kidney transplantation(treatment group).Survival time of renal allografts was observed and splenic cell reaction of the recipients to donors and the third party antigens were assayed by means of MTT on the 20~(th)postoperative day.Results Survival time of renal allografts in treatment group was prolonged significantly as compared with controls ((62.1)?(13.7) days vs(8.6)?(0.9) days,P