| Backgrounds: The incidence of multiple myeloma (MM) is climbing in our country. They are influencing quality and survival of MM patients severely. MM has been considered as an incurable disease up to now. However, conventional therapies cannot prolong the disease free survival (DFS) and overall survival (OS). The minimal residual diseases (MRD) are always the major causes for MM resistant to drugs and relapse. Therefore, novel therapeutic strategies aiming at eliminating MRD are much needed. Immunotherapy for malignant tumors has been developed rapidly since 1980? Recent studies have focused on the adoptive immunotherapy for malignancies mediated by cytotoxic lymphocyte (Cm). As we all know, antigen recognition. procession, presentation and T cells pulsing and activating all rely on the participation of antigen presenting cells (APCs). During the past decades, dendritic cells have been identified as the most potent APCs. They are extremely efficient at antigen capture and presentation antigens to nae T cells. They express MHC molecules, co- stimulating and adhesion molecules on cell surface. Thus, DCs are ideal APCs for mediating tumor antigen specific Cm response. Basing upon what mentioned above, we plan to induce MM specific CTh mediated by autologus DCs, which pulsed with MM antigens. Objective: First, to explore the proper concentration of IFN a and GM-CSF for DCs generation. Second, to compare DCs generating from MM patients with these from healthy volunteers by morphology, quantity, inimunotype, and function. Third, to induce myeloma specific cytotoxic T cells response in vitro mediated by autologus dendritic cells derived from MM patients. Methods: Monocytes isolated from the peripheral blood of healthy volunteers were cultured in SOOu/m1 of GM-CSF and different concentration of IFN a for 8 days to generate DCs. Their outputs and inimunotype were observed in order to select a proper concentration of IFN a. Then, we applied 800u/ml of GM-CSF and 600u/ml IFN a in serum free medium to generate DCs from MM patients and volunteers. Eight days later, their morphology and immunotype were analyzed by FCM.. Mixed lymphocyte reaction (MLR) was also performed to evaluate their function. Furthermore, DCs derived from MM patients were pulsed by U2 cells treated with mitomycin C and the cell lysates and incubated with autologus T lymphocytes for 5? days to induce antigen specific CTh. MIT assay was performed in order to examine the U2 cell specific lysis. Results: DCs generated both from MM patients and volunteers carried a typical dendritic like morphology, they expressed class II MHC, co-stimulating molecules (such as CD4O, CD86) and adhesion molecules(CD54) highly on their surface(>85%), but CD83 was lower expressed(7.l±2% and 8.2±0.1%, respectively) compared with DCs generated in GM-CSF/IL-4. There was no significance in outputs and positive percentage of CD4O, CD54, CD86, HLA-DR (p>0.05) between the tow groups. They could stimulate proliferation of allogeneic T lymphocytes similarly. Specific killing of U2 cells mediated by DCs were tested with MTT assay. At an effector/target ratio of 20/1, specific cytotoxicity activities against U2 cells(28.0± 7.6% and 21.2±0.4%, respectively,) were observed, but without antigen stimulation, the killing rate was 11.7±0.3% and 9.5±0.8% respectively, without DC mediation, the killing rate was 15.6±0.8% and 13.1±5.5% (p |
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