热处理肿瘤细胞抗原负载树突细胞抗小鼠结肠癌效应

研究了热处理肿瘤细胞抗原负载骨髓来源的树突细胞（dendritic cell,DC）对结肠癌小鼠的治疗作用.将小鼠结肠癌细胞CT26热处理后超声破膜,以其细胞裂解液负载BALB/c小鼠骨髓来源的DC,观察DC诱导肿瘤特异性细胞毒性T淋巴细胞（cytotoxic T lymphocyte,CTL）杀伤活性;并将DC接种于荷瘤小鼠皮下,观察其对肿瘤生长的抑制作用及对荷瘤小鼠生存期的影响.发现致敏DC诱导的CTL对CT26肿瘤细胞具有显著的杀伤作用.用致敏DC免疫小鼠后,对小鼠肿瘤的生长具有显著的抑制作用,并能显著延长荷瘤小鼠的生存时间.热处理肿瘤细胞抗原负载的树突细胞对结肠癌小鼠具有显著的治疗效果.     

p53转染黑色素瘤细胞修饰的树突状细胞疫苗体外抗肿瘤作用的研究

利用野生型p53质粒转染黑色素瘤B16细胞,反复冻融法提取p53修饰的肿瘤抗原(p53-Ag),将抗原体外冲击同基因小鼠骨髓来源的树突状细胞(dendritic cells,DC)制备特异性DC肿瘤疫苗;观察DC诱导的淋巴细胞增殖反应和细胞毒性T淋巴细胞(cytotoxic T lymphocytes,CTL)对黑色素瘤细胞的细胞毒效应,分析其诱导肿瘤抗原特异性免疫应答的机制。结果显示,p53-肿瘤抗原冲击的DC可显著刺激淋巴细胞增殖,其诱导的CTL效应对肿瘤细胞也有很好的杀伤效果。     

体内致敏的树突状细胞诱导特异性抗肿瘤免疫的基础研究

目的证实树突状细胞（dendritic cells,DC）可在体内通过吞噬凋亡肿瘤细胞获取抗原物质,探讨其在肿瘤免疫治疗中的意义.方法以615小鼠的前胃癌细胞株造模,在体外用rmGM-CSF和rmIL-4从荷瘤小鼠骨髓细胞分化、诱导未成熟树突状细胞.分为4组：小剂量化疗组、树突状细胞组、小剂量化疗＋树突状细胞组和对照组,以BAX试剂盒检测肿瘤细胞凋亡.在瘤体内注射树突状细胞,观察给药侧瘤体及对侧瘤体体积,生存期,和特异性细胞毒性T淋巴细胞（CTLs）对肿瘤细胞的特异性杀伤作用.结果小剂量化疗能诱导肿瘤细胞凋亡.小剂量化疗后瘤内应用树突状细胞,给药侧瘤体及对侧瘤体体积明显缩小（P＜0.05）,小鼠的生存率提高,体内凋亡肿瘤细胞致敏的DC诱导的CTL对MFC有显著的杀伤作用,在效靶比为40：1、20：1、10：1和5：1时72 h的杀伤率分别为87.64%、70.32%、34.63%和13.87%.并能特异性杀伤小鼠前胃癌细胞MFC（P＜0.01）.结论体外诱导分化的未成熟DC,能于体内捕获小剂量化疗诱导的凋亡肿瘤细胞所携带的肿瘤抗原,诱导机体特异性抗肿瘤免疫反应.     

Hs-exosomes致敏树突状细胞介导的抗卵巢癌免疫治疗的实验研究

目的检测卵巢癌细胞的外排小体Hs-exosomes致敏树突状细胞DC诱导T淋巴细胞CTL特异性杀伤卵巢癌细胞的能力。方法:分离卵巢癌细胞株2780释放的Hs-exosomes,将其致敏DC并与T淋巴细胞共培养,检测CTL体外细胞毒活性。结果:Hs-exosomes致敏DC激活CTL的抗肿瘤能力显著高于未致敏DC组。结论:2780细胞释放的Hs-exosomes致敏DC激活T淋巴细胞对肿瘤具有很强的杀伤作用。     

树突状细胞对小剂量化疗疗效影响的基础研究

目的 研究树突状细胞对小剂量化疗疗效的影响,探讨小剂量化疗的可能机制.方法 以615小鼠的前胃癌细胞株(MFC)造模,在体外用rmGM-CSF和rmIL-4从荷瘤小鼠骨髓细胞分化、诱导未成熟树突状细胞.分为4组:小剂量化疗组、树突状细胞组、小剂量化疗+树突状细胞组、对照组,以BAX试剂盒检测肿瘤凋亡情况.在瘤体内注射树突状细胞,计算抑瘤率、特异性细胞毒性T淋巴细胞(CTL)的增殖及其对肿瘤细胞的特异性杀伤作用.结果 小剂量化疗能诱导肿瘤细胞凋亡,BAX 基因产物表达增多.注射侧抑瘤率小剂量化疗+DC组、小剂量化疗组、DC组分别为100%、67.22%和57.98%.对侧抑瘤率小剂量化疗+DC组、小剂量化疗组、DC组分别为87.58%、59.69%和48.24%.体内凋亡肿瘤细胞致敏的DC能显著刺激T淋巴细胞增殖,其诱导的CTL对MFC有显著的杀伤作用,在效靶比为40∶ 1、20∶ 1、10∶ 1和5∶ 1时72 h杀伤率分别为87.64%、70.32%、34.63%和13.87%.并能特异性杀伤小鼠前胃癌细胞MFC(P<0.01).结论 小剂量化疗的机制与肿瘤细胞凋亡及免疫促进有一定的相关.     

负载肿瘤细胞抗原的树突状细胞联合奥沙利铂抑制胰腺癌细胞BxPC-3增殖的实验研究

目的：化疗是晚期胰腺癌的主要治疗手段,但临床效果有限。为提高胰腺癌化疗效果,本研究将化疗药物奥沙利铂（OXA）联合肿瘤全细胞抗原负载的树突状细胞（DC）体外作用于胰腺癌BxPC-3细胞系,观察对其增殖的影响。方法：自健康人外周血中分离培养DC和T细胞。反复冻融BxPC．3细胞,使其裂解并提取全细胞抗原后致敏DC,再以DC激活T细胞。ELISA检测T细胞培养上清中IL-2、IL-4、IL-10和IFN-g的含量。将T细胞与不同浓度的OXA联合作用于BxPC-3细胞,MTT法检测杀伤率。结果：负载BxPC．3全细胞抗原的DC能显著激活T细胞使其成为效应性T细胞,并使其分泌IL-2和IFN—Y。不同浓度的OXA与效应性T细胞联合作用于BxPC．3细胞可明显抑制其增殖,且杀伤效果与OXA的浓度呈正相关。结论：负载BxPC-3全细胞抗原的DC可诱导出抗肿瘤的效应性T细胞,联合OXA能显著提高对BxPC-3细胞的杀伤作用。生物治疗联合化疗抑制胰腺癌细胞增殖的作用明显,具有较好的临床应用前景。     

人脐血CD34+细胞来源的树突状细胞疫苗在SCID小鼠体内的抗肿瘤免疫作用

目的观察脐血CD34 干细胞来源的树突状细胞(dendritic cells, DC)疫苗在严重联合免疫缺陷(severecombined immunity deficiency,SCID)小鼠体内对人肝癌细胞的免疫治疗和免疫保护作用.方法采用微磁珠分选系统(Mini MACS)从脐血单个核细胞中分离CD34 干细胞.重组人粒细胞-巨噬细胞集落刺激因子(recombined human granulocyte-macrophage colony-stimulating factor, rhGM-CSF)、重组人肿瘤坏死因子(recombined human tumor necrosis factor,TNF)-α诱导脐血CD34 细胞向DC分化,相差显微镜下观察DC分化过程中细胞的形态及数量变化.用人肝癌细胞BEL-7402裂解物冲击DC制备DC疫苗.在SCID小鼠体内观察DC疫苗致敏的淋巴细胞对人肝癌细胞的免疫治疗和免疫保护作用.结果脐血CD34 细胞在细胞因子诱导下,细胞形态由小变大、由圆形逐渐变为不规则形;细胞分裂扩增过程中,数量逐渐增多,形成细胞集落.经过细胞因子联合诱导2周的DC胞质突起丰富,具有典型的树枝状形态.在体内的抗肿瘤实验中,经DC疫苗致敏的人外周血淋巴细胞治疗荷瘤小鼠,肿瘤生长速度、瘤体积和重量明显小于未致敏淋巴细胞治疗组(P<0.05).与未致敏淋巴细胞免疫组和DC疫苗致敏的淋巴细胞治疗组比较,经DC疫苗致敏的淋巴细胞免疫SCID小鼠,肝癌细胞攻击后,肿瘤的发病率降低(P<0.05),发病潜伏期延长(P<0.01),肿瘤体积和重量减小(P<0.05).结论人脐血CD34 细胞来源的DC疫苗能在一定程度上抑制人肝癌细胞在小鼠体内的生长,抵抗肿瘤细胞的攻击,对机体具有相应的抗肿瘤免疫治疗和免疫保护作用.     

丹参提取物F对幽门螺杆菌致敏小鼠的免疫调理作用研究

研究丹参提取物F（DanShenextractF,DSE－F）对幽门螺杆菌（Helicobacterpylori,HP）致敏胃粘膜固有层淋巴细胞有无免疫调理作用。经口给予小鼠HP全菌破碎抗原与DSE－F2周后,提取脾淋巴细胞和胃粘膜固有层T淋巴细胞（LPL）,检测对肿瘤细胞的细胞毒活性和IL－2诱生能力的改变。结果显示DSE－F与HP抗原协同能增强脾淋巴细胞和胃LPL细胞的抗肿瘤细胞的细胞毒性;对HP抗原致敏胃粘膜有免疫调理作用。     

NK细胞和NKT细胞发育的转录调控

自然杀伤（natural killer,NK）细胞和自然杀伤T（natural killer T,NKT）细胞是参与机体抗病毒免疫和肿瘤免疫的两群淋巴细胞亚群,是介导先天性免疫（innate immunity）应答和调节适应性免疫（adaptive immunity）应答的重要效应细胞。近年来,随着对NK细胞和NKT细胞及其转录调控因子研究的不断深入,NK细胞和NKT细胞的发育机制逐步被阐明,这将为提高NK细胞和NKT细胞的抗病毒和肿瘤免疫疗效提供新的策略。     

葛根素对U14宫颈癌小鼠血液流变学、脾淋巴细胞增殖及细胞毒性影响

摘要 目的：研究葛根素治疗对U14宫颈癌小鼠血液流变学、脾淋巴细胞增殖活性及对宫颈癌细胞毒性的影响。方法：45只雌性昆明小鼠随机分为对照组、模型组和葛根素组。模型组和葛根素组小鼠通过腋下注射U14小鼠宫颈癌细胞建立U14宫颈癌移植瘤小鼠,并且葛根素小鼠通过葛根素灌胃进行治疗,对照组和模型组小鼠给予等量生理盐水。比较各组小鼠血流变学、脾淋巴细胞增殖活性及对宫颈癌细胞毒性。结果：经葛根素治疗的葛根素组宫颈癌小鼠肿瘤重量显著低于模型组小鼠（P<0.05）,葛根素治疗宫颈癌小鼠的抑瘤率是（42.91±12.91）%。宫颈癌小鼠低切/高切全血粘度、血浆粘度值以及血细胞比容均显著升高（P<0.05）,而葛根素治疗可显著降低宫颈癌小鼠低切/高切全血粘度、血浆粘度值以及血细胞比容（P<0.05）。宫颈癌小鼠脾脏重量、脾脏指数和脾淋巴细胞体外增殖能力均显著下降（P<0.05）,而葛根素治疗可显著提高宫颈癌小鼠脾脏重量、脾脏指数和脾淋巴细胞体外增殖能力（P<0.05）。此外,经葛根素治疗的宫颈癌小鼠脾淋巴细胞对U14宫颈癌细胞细胞毒性显著高于模型组宫颈癌小鼠（P<0.05）。结论：葛根素治疗可降低U14宫颈癌小鼠血液粘度、改善血流变性质,并且可以提高脾淋巴细胞的增殖活性和对宫颈癌细胞的杀伤力。     

Protective effects of diosmetin extracted from Galium verum L. on the thymus of U14-bearing mice

Diosmetin (DGVL) extracted from the traditional Chinese herb Galium verum L. has been found to have anticancer activity. In this study, the effects of DGVL on the thymus of U14-bearing mice were investigated. Using flow cytometry, peripheral blood lymphocytes were characterized based on the expression of surface markers for T helper cells (CD4(+)) and T suppressor cells (CD8(+)). Serum levels of tumor necrosis factor α (TNF-α), interleukin-2 (IL-2), IL-10, and transforming growth factor β1 (TGF-β1) and a cell proliferation assay were determined with an enzyme-linked immunosorbent assay. The expression of Fas and Fas ligand (FasL) on the thymus was determined by Western blotting. Our results showed that DGVL inhibited tumor growth and significantly increased the thymus weight compared with the control. Also, DGVL elevated serum levels of IL-2 and significantly reduced levels of TNF-α, TGF-β1, and IL-10 in a dose-dependent manner. Histological study and terminal dUTP nick end labeling staining results showed that DGVL protected thymus tissue against the onslaught of tumor growth by inhibiting thymus lymphocyte apoptosis. The cell proliferation assay revealed that DGVL might promote more thymus lymphocytes towards proliferation. Furthermore, the ratio of CD4(+)/CD8(+) T lymphocytes was significantly increased from 0.69 to 2.29 by treatment with DGVL. Immunoblotting analyses revealed that the expression of Fas and FasL on the thymus was lower in mice in the DGVL treatment group than in the control mice. In conclusion, DGVL can inhibit tumor growth and protect tumor-induced apoptosis of the thymus, and the mechanism is closely associated with reduced cell death in the thymus and a Fas-FasL-dependent pathway.     

Sensitization of T lymphocytes in vitro by syngeneic macrophages fed with tumor antigens.

We investigated the interaction between T lymphocytes and macrophages in the vitro sensitization of lymphocytes against tumor cells. Spleen cells were sensitized in vitro by syngeneic peritoneal macrophages that had been fed with cell-free antigen preparation of syngeneic tumor cells. The sensitized T lymphocytes acquired specific cytotoxic cells. The sensitized T lymphocytes acquired specific cytotoxic activity in vitro and the capacity to inhingeneic fibroblasts, or the antigen preparation by itself were not able to sensitize the lymphocytes against the tumor.     

Exosomes derived from dendritic cells

Dendritic cells (DC) are potent antigen presenting cells and the only ones capable of inducing primary cytotoxic immune responses both in vivo and vitro. DCs secrete a 60-80 nm membrane vesicle population of endocytic origin, called exosomes. The protein composition of exosomes was analyzed using a systematic proteomic approach. Besides MHC and costimulatory molecules, exosomes bear several adhesion proteins, probably involved in their specific targeting. Exosomes also accumulate several cytosolic factors, most likely involved in exoxome's biogenesis in late endosomes. Like DCs, exosomes induce potent anti tumor immune responses in vivo. Indeed, a single injection of DC-derived exosomes sensitized with tumor peptides induced the eradication of established mouse tumors. Tumor-specific cytotoxic T lymphocytes were found in the spleen of exosome treated mice, and depletion of CD8+ T cells in vivo inhibited the anti tumor effect of exosomes. These results strongly support the implementation of human DC-derived exosomes for cancer immunotherapy.     

Induction of CML28-specific cytotoxic T cell responses using co-transfected dendritic cells with CML28 DNA vaccine and SOCS1 small interfering RNA expression vector

CML28 is an attractive target for antigen-specific immunotherapy. SOCS1 represents an inhibitory control mechanism for DC antigen presentation and the magnitude of adaptive immunity. In this study, we evaluated the potential for inducing CML28-specific cytotoxic T lymphocytes (CTL) responses by dendritic cells (DCs)-based vaccination. We constructed a CML28 DNA vaccine and a SOCS1 siRNA vector and then cotransfect monocyte-derived DCs. Flow cytometry analysis showed gene silencing of SOCS1 resulted in higher expressions of costimulative moleculars in DCs. Mixed lymphocyte reaction (MLR) indicated downregulation of SOCS1 stronger capability to stimulate proliferation of responder cell in DCs. The CTL assay revealed transfected DCs effectively induced autologous CML28-specific CTL responses and the lytic activities induced by SOCS1-silenced DCs were significantly higher compared with those induced by SOCS1-expressing DCs. These results in our study indicates gene silencing of SOCS1 remarkably enhanced the cytotoxicity efficiency of CML28 DNA vaccine in DCs.     

Treatment of established colon carcinoma-bearing mice by dendritic cells pulsed with lysates of heat-treated tumor cells

To investigate the therapeutic effect of dendritic cells pulsed with lysates of heat-treated CT26 colon carcinoma cells. Bone marrow-derived DCs were pulsed with lysates of heat-treated tumor cells and were used to immunize BALB/c mice with established colon carcinoma. Cytotoxic T lymphocyte (CTL) response was detected. The therapeutic effect induced by DCs was observed by tumor weight and survival time. DCs pulsed with lysates of heat-treated tumor cells markedly induced specific cytotoxic activity of CTLs...     

Suppressor factor from tumor-allosensitized spleen cells--its effect on in vitro proliferation of tumor cells and in vivo skin allograft survival

C57BL/6 mice are sensitized ip with allogeneic P-815 mastocytoma cells. Fifteen days later the spleen cells of the sensitized mice are used in the production of suppressor factor or treated with mitomycin and used as suppressor cells. Sensitized spleen cells incubated with the specific alloantigen (DBA/2 m-treated spleen cells) release suppressor factor (SF)² which inhibits cell proliferation in mixed lymphocyte culture (MLC) as well as the in vitro generation of cytotoxic cells (CML). SF is most effective when added eary during MLC. SF also inhibits mitogen responsiveness of normal spleen cells. In addition to inhibiting lymphocyte function in vitro, suppressor cells as well as SF inhibit the in vitro proliferation of tumor cells. This inhibition is specific for the tumor to which the suppressor cells are induced. The inhibition of tumor cell proliferation is not due to the presence of cytotoxic cells in the spleen of the tumor-allosensitized mice. Suppressor cells from neonatal mice do not inhibit the in vitro proliferation of tumor cells. SF injected iv into C57BL/6 mice decreases the mixed lymphocyte reactivity of the host spleen cells and decreases the ability of the host to reject skin allografts. We interpret these data to suggest that tumor-allosensitized spleen cells, and the SF they produce, not only affect lymphocyte function but also inhibit tumor cell proliferation. This dual effect of suppressor cells could be an important part of the immune surveillance against tumors.     

Immunomodulatory drugs improve the immune environment for dendritic cell-based immunotherapy in multiple myeloma patients after autologous stem cell transplantation

Multiple myeloma (MM) is characterized by a malignant proliferation of plasma cells in the bone marrow with associated organ damage. Although the prognosis of MM has improved recently, the disease remains incurable for the large majority of patients. The eradication of residual disease in the bone marrow is a main target on the road toward cure. Immune cells play a role in the control of cancer and can be tools to attack residual MM cells. However, the myeloma-associated immune deficiency is a major hurdle to immunotherapy. We evaluated ex vivo the effects of low doses of the immunomodulatory drugs (IMiDs) lenalidomide and pomalidomide on several immune cell types from MM patients after autologous stem cell transplantation and with low tumor burden. We observed that these drugs increased CD4⁺ and CD8⁺ T-cell proliferation and cytokine production, enhanced the lytic capacity of cytotoxic T lymphocytes and reduced the suppressive effects of regulatory T cells on CD8⁺ T-cell responses. In addition, we found that functional dendritic cells (DCs) can be generated from mononuclear cells from MM patients. The presence of IMiDs improved the quality of antigen-specific T cells induced or expanded by these DCs as evidenced by a higher degree of T-cell polyfunctionality. Our results provide a rationale for the design of early phase clinical studies to assess the efficacy of DC-based immunotherapy in combination with posttransplant maintenance treatment with IMiDs in MM.     

The multicellular tumor spheroid model: I. Characterization of the allograft response in sensitized mice

Intraperitoneal implants of multicellular spheroids of EMT6 mammary sarcoma cells into specifically sensitized allogeneic mice have been used as a model to study in situ immunity to solid tumor allografts. Morphological examination of the spheroids recovered from sensitized mice revealed massive infiltration by host cells. There was an early but apparently nonspecific infiltration by large numbers of polymorphonuclear leukocytes followed by the infiltration of large numbers of macrophages and smaller numbers of lymphocytes. The later infiltration correlated with tumor cell killing as determined by a cloning assay for surviving EMT6 cells, and with the presence of cells with cytotoxic activity in in vitro assays. The kinetics of tumor cell killing indicated that tumor cell survival decreased within a few hours of spheroid implantation and less than 1% of the tumor cells survived after 48 h. Purification of the infiltrating cells by nylon wool fractionation and by treatment with anti-T-cell serum and complement indicated that the primary cytotoxic cell is a T lymphocyte.