树突状细胞介导的CTL在裸鼠体内外抑制白血病细胞生长的研究

目的研究白血病细胞可溶性蛋白抗原（SPA）致敏树突状细胞（DC）介导的细胞毒性T淋巴细胞（CTL）反应在裸鼠体内、外抑制白血病细胞生长的效应,为白血病DC免疫治疗提供理论依据。方法利用人骨髓单个核细胞（MNC）体外培养DC,经形态、表型及功能综合鉴定。用纳米粒包裹白血病细胞SPA并致敏DC,在体外诱导出特异性CTL,用MTT法测定其活性。另分别将HL-60细胞与淋巴细胞（LC）或与CTL同时注入裸鼠体内,通过肿瘤体积、成瘤时间、肿瘤抑制率等对比各组抑制肿瘤生长的效果。结果（1）培养的DC具有DC的形态特征并高表达CD1a、CD83。（2）MTT法测定各组CTL活性,发现A1组较A2组和A3组、B1组较B2组和B3组有明显差异（均P〈0.05）。A3组及B3组CTL活性最高,A2组及B2组活性次之。（3）在裸鼠体内实验中,1组与2组、3组的肿瘤体积及成瘤天数比较均有明显统计学差异（P〈0.05）,而2组与3组比较却无显著性差异（P〉0.05）;2组与3组肿瘤抑制率分别为（50.70±13.74）%和（52.29±13.68）%。结论在体外实验用白血病细胞SPA及纳米粒包裹的SPA致敏DC,均能可介导较强的CTL作用,且纳米粒包裹SPA组的CTL活性更高。用白血病细胞SPA及纳米粒包裹的SPA致敏的DC在裸鼠体内同样可诱导出较强的CTL作用,表现为肿瘤体积明显小于对照组,成瘤天数也明显晚于对照组,但纳米粒包裹SPA致敏DC组在体内试验中未显示出更强的抑瘤活性。通过DC介导特异性的CTL可有效的抑制白血病细胞,是一种有良好临床应用前景的细胞免疫治疗方法。     

树突状细胞疫苗对人肺腺癌GLC-82细胞体外杀伤作用的实验观察

目的 通过建立负载人肺腺癌细胞株GLC-82可溶性抗原的树突状细胞(DC)疫苗,探讨应用DC疫苗的致敏特异性杀伤性T细胞(CTL)体外杀瘤细胞的可行性和实验条件,为后期l临床应用提供实验依据.方法 通过用定量摩尔氯化钾提取法获得人肺腺癌细胞GLC-82的可溶性抗原多肽(TSA),从人外周血单核细胞(PBMC)中用GM-CSF、白细胞介素-4和肿瘤坏死因子-α体外诱导扩增并鉴定获取DC,构建DC疫苗;利用DC疫苗刺激同种异体外周血T淋巴细胞活化增殖,诱导产生具有识别肺癌细胞抗原的特异性CTL的可行性及MTT法检测该CTL对GLC-82、肺癌CALU-6和人红白血病K 562细胞的体外杀伤效应.结果 人PBMC体外经7d诱导出的DC,经形态学、免疫组化证实具有典型的树突状细胞特性;负载GLC-82抗原的DC疫苗能有效诱导同种异体T淋巴细胞活化增殖产生CTL,最适浓度为1:10;诱导活化的CTL对靶细胞的杀伤活性明显高于未经肿瘤抗原致敏的组.结论 诱导培养人外周血PBMC中的Mo可获取大量DC,诱导出的DC功能较强,适宜临床应用;DC疫苗能强烈刺激初始型同种异体T淋巴细胞增殖产生CD 8+表达增加的CTL;激活的CTL对肺癌靶细胞发挥高效而特异的细胞毒效应,对非肺组织瘤靶细胞也具有非特异性杀伤效应.     

脐带血与外周血来源树突细胞体外刺激特异抗白血病T细胞免疫应答

目的：比较脐血（CB）及外周血（PB）单个核细胞（MNC）体外诱导生成树突状细胞（DC）的产量;并将此DC负载白血病抗原,检测两者诱导的特异性细胞毒T细胞（CTL）对白血病细胞的杀伤活性。方法：取CB及健康成人PB各8份,以淋巴细胞分离液分离获得MNCs,培养体系中加入重组人粒单核细胞集落刺激因子（rhGM-CSF）,重组人白细胞介素4（rhIL-4）和肿瘤坏死因子α（TNF-α）,并在培养第5天,加入HL-60细胞经反复冻融提取的抗原,致敏DC。培养过程中,观察树突状细胞形态,流式细胞仪（FCM）检测表型。培养第12天收获成熟DC,CB组分别与8例PB来源T淋巴细胞共培养;PB组与自体T淋巴细胞共培养,诱导产生白血病特异性CTL,乳酸脱氢酶法（LDH法）测定溶靶细胞活性。结果：（1）CB与PB来源DC均表现出成熟DC典型形态和免疫表型特征,2组DC相关分化抗原CD1a、CD83、CD86、CD80和人类白细胞相关抗原DR（HLA-DR）的表达较培养前增高,2组比较差异无统计学意义（P〉0.05）。（2）CB组DC产量高于PB组,差异有统计学意义（P〈0.01）。（3）以白血病抗原冲击的DC所刺激的T淋巴细胞对白血病靶细胞显示出明显的杀伤活性,按照各效靶比进行两者的比较,差异无统计学意义（P〉0.05）。结论：利用细胞因子体外诱导CB及PB来源MNCs均能产生大量成熟DC,且功能相同;前者DC产量更高,来源丰富,可能成为急性白血病免疫治疗中DC的丰富来源。     

多表位BCR—ABL融合抗原体外诱导对白血病原代细胞的特异性杀伤

目的 体外观察多表位BCR—ABL融合抗原诱导对白血病细胞的特异性杀伤效应，探索慢性髓细胞性白血病(chronic myeloid leukemia，CML)免疫治疗新途径。方法从外周血单个核细胞培养DC，以BCR—ABL融合抗原脉冲刺激DC，诱导特异性CTL产生；MTT法检测CTL对白血病靶细胞的特异性杀伤活性。结果 融合抗原刺激产生的CTL能特异性杀灭含BCR—ABL融合基因的白血病靶细胞。结论 我们所设计表达的多表位BCR—ABL融合抗原能在体外诱导特异性抗白血病免疫反应，对白血病细胞产生特异性杀伤，为进一步的体内的实验奠定了基础。     

灵芝多糖对体外树突状细胞诱导细胞毒性T-淋巴细胞的调节作用(英文)

目的:研究灵芝多糖(Gl-PS)在抗原提呈阶段对体外培养树突状细胞(DC)诱导特异性细胞毒性T-淋巴细胞(CTL)功能的调节及其机制。方法:体外培养小鼠骨髓来源DC经P815肿瘤细胞冻融抗原冲击致敏,并与不同浓度Gl-PS(0.8,3.2,或12.8 mg/L)共培养。成熟DC与脾淋巴细胞共培养诱导P815特异性CTL生成。第5天收集各组悬浮细胞及培养上清,采用乳酸脱氢酶法比较CTL特异性杀伤活性;RT-PCR法测定T扰素γ(IFNγ)及颗粒酶B mRNA在CTL的表达;ELISA或Western blot法检测IFNγ或颗粒酶B蛋白的表达。结果:3种浓度的Gl-PS均可增高培养上清中释放的LDH活性(P<0.01);增加CTL表达IFN7及颗粒酶B mRNA(IFNγ:Gl-PS 12.8 mg/L组与RPMI-1640组,P<0.05;颗粒酶B:P<0.01);促进CTL培养上清中IFNγ蛋白生成(P<0.05)以及CTL表达颗粒酶B蛋白(Gl-PS 12.8 mg/L组与RPMI-1640组,P<0.05)。结论:Gl-PS可在抗原提呈阶段促进P815肿瘤冻融抗原冲击致敏DC所诱导的特异性CTL的杀伤活性,其机制可能是通过IFNγ及颗粒酶B途径的调节。     

致敏树突状细胞疫苗抗小鼠乳腺癌的实验研究

目的研究以EMT6乳腺癌细胞致敏的树突状细胞(DC)疫苗的抗肿瘤作用。方法无菌取小鼠骨髓细胞,在体外培养条件下经细胞因子诱导为DC,用EMT6肿瘤细胞冻融抗原冲击致敏DC,检测经DC免疫产生的细胞毒T淋巴细胞(CTL)体外杀伤肿瘤细胞的活性。建立EMT6荷瘤小鼠模型,随机分为实验组、实验对照组和空白对照组,于肿瘤接种后第7、14天给予相应DC疫苗治疗,观察致敏DC免疫对小鼠乳腺肿瘤模型的治疗作用。结果致敏DC诱导生成的特异性CTL在体外对肿瘤细胞可产生杀伤作用,与PBS对照组比较,差异有显著性(P<0.05);经致敏DC注射免疫后,小鼠移植瘤得到抑制,与PBS对照组比较,差异有显著性(P<0.05)。结论以EMT6乳腺癌细胞致敏的树突状细胞(DC)疫苗在体外和小鼠体内均显示了抗肿瘤作用。     

K562白血病株树突状细胞诱导及其抗肿瘤功能的体外研究

目的将K562细胞诱导分化为树状突细胞(DC),并以K562-DC作为刺激细胞诱导细胞毒T淋巴细胞(CTL)反应,观察其体外特异性抗肿瘤效应,对白血病细胞来源DC用于白血病免疫治疗进行初步探讨。方法(1)低浓度丙戊酸钠将K562细胞诱导分化为DC(K562-DC)。(2)DC的鉴定:①形态学:倒置显微镜(Olympus)下观察细胞形态并摄相。②免疫表型:PE结合的鼠抗人CD1a、HLADR、CD83、CD80及CD86单抗用流式细胞仪分析检测细胞表面标志。③功能鉴定:采用同种异体混合淋巴细胞反应。(3)MTT杀伤实验检测DC诱导特异性细胞毒性T淋巴细胞的杀伤活性。结果(1)丙戊酸钠(VPA)培养第7天时,细胞均匀分散,变形,体积增大,数量增多,细胞表面可见多个突起,且具有刺状突起的细胞数量较前增多。(2)通过流式细胞术检测诱导的K562DC表面分子的表达,结果发现丙戊酸钠(VPA)诱导的K562DC各表面标志的表达,与K562细胞相比均明显上调(P<0.05)。(3)丙戊酸钠(VPA)诱导的K562DC具有较强的诱导CTL杀伤肿瘤细胞的能力且随效靶比例增高而增强,并显著高于未负载肿瘤可溶性抗原的DC及单纯T细胞组(P<0.05)。结论以K562细胞为靶细胞,观察VPA对K562细胞诱导向树突状细胞分化作用。进一步的实验证实,VPA可以诱导K562细胞向树突状细胞分化,而且诱导的树突状细胞具有较强的抗原呈递功能和诱导特异性细胞毒性T淋巴细杀伤活性作用。     

慢性粒细胞性白血病抗原负载树突状细胞激发抗白血病作用

目的研究慢性粒细胞性白血病(CML)细胞冻融抗原(CLA)负载的树突状细胞(DC)对特异性抗白血病T细胞的作用.方法将CML患者外周血单个核细胞(PBMNC)来源的DC在体外用CLA负载,再与CML患者的经细胞因子诱导的杀伤细胞(CIK)共同培养,应用乳酸脱氢酶(LDH)释放法观察其对自身CML细胞杀伤活性(A组),与未负载的DC+CIK(B组)、CIK(C组)及CIK+CLA(D组)进行比较.结果效靶比为10∶1条件下,A、B、C、D4组的杀伤活性分别为(63.69±8.35)%、(45.02±5.49)%、(27.28±4.64)%、(29.63±5.71)%.A组比B组杀伤活性强(P＜0.01);C组与D组比无显著性差异.结论CLA负载的DC可进一步提高DC介导的特异性抗白血病T细胞对CML细胞的杀伤活性.     

胎儿来源的树突状细胞诱导抗膀胱癌效应的研究

目的：研究胎儿来源的树突状细胞（DC）体外诱导抗膀胱癌的特异性细胞免疫的效果.方法：从胎儿骨髓获得单个核细胞,经粒细胞-单核细胞集落刺激因子（GM-CSF）、IL-4和TNF-α诱导产生DC.利用50%～70%硫酸铵饱和沉淀法获取膀胱癌细胞系EJ含热休克蛋白（HSP）成分的细胞溶解物,以该抗原负载DC,激活胎脾细胞产生肿瘤特异性的细胞杀伤性T淋巴细胞（CTL）.利用IL-2刺激胎脾细胞产生LAK细胞.应用MTF法分别检测CTL和LAK细胞对EJ细胞的杀伤效应.结果：胎儿骨髓可诱导出功能成熟的DC,高表达CD1a、CD86、HLA-DR和CD83.负载EJ抗原的DC可诱导产生CD8＋CTL.其对EJ细胞的杀伤作用明显强于LAK细胞.结论：含HSP成分的肿瘤细胞溶解物负载胎儿来源的DC,体外可诱导出更强的特异性抗肿瘤免疫应答.     

热休克蛋白gp96-肽复合物体外对人肝癌细胞的抗肿瘤效应

目的研究热休克蛋白gp96-肽复合物修饰树突状细胞(DC)后对人肝癌细胞的体外特异抗肿瘤效应。方法从人原发性肝癌组织中提取gp96-肽复合物,用其修饰DC细胞后与T淋巴细胞共同培养,以MTT法检测该复合物介导的细胞毒性T细胞(CTL)对不同来源人肝癌细胞的抗肿瘤效应,并与粗提抗原修饰DC细胞组相比较。结果 gp96-肽复合物诱导的CTL对原代肝癌细胞杀伤效率为74.3%,明显高于粗提抗原组(42.5%)和未加抗原组(14.4%)(P<0.01),粗提抗原组对肝癌细胞杀伤效率高于未加抗原组(P<0.01)。且该复合物的抗肿瘤效应具有一定的组织特异性。结论 gp96-肽复合物修饰的DC细胞,在体外能刺激产生特异的抗肿瘤细胞毒性T细胞,因而热休克蛋白gp96在肿瘤免疫治疗中具有重要的实用价值。     

Fusogenic liposome can be used as an effective vaccine carrier for peptide vaccination to induce cytotoxic T lymphocyte (CTL) response

We reported previously that fusogenic liposome (FL) introduced antigen protein encapsulated in the liposome directly into the cytoplasm of the antigen presenting cells, and that it induced immune responses. In the present study, we encapsulated TAX38-46, an HTLV-I derived protein and an antigen peptide model, into FL. The ability to induce effective cytotoxic T lymphocytes (CTL) responses in immunized mice was evaluated. Results showed FL could induce CTL response effectively and suggested that FL is a potential peptide vaccine carrier.     

树突状细胞瘤苗诱导的抗神经胶质瘤作用体外实验研究

目的 :研究负载自体神经胶质瘤抗原的树突状细胞 (DCs)瘤苗在体外诱导的特异性细胞毒性淋巴细胞 (CTL)对神经胶质瘤细胞的杀伤效应。方法 :以组合酶消化法从新鲜神经胶质瘤手术标本中获取神经胶质瘤细胞 ,冻融制备神经胶质瘤抗原。GM -CSF、IL -4体外诱导外周血单个核细胞 (PBMC)获得DCs并负载神经胶质瘤抗原 ,继而以其刺激自体T淋巴细胞制备神经胶质瘤抗原特异性CTL ;用CytoTox96TM检测CTL对患自身神经胶质瘤细胞体外杀伤效应。结果 :负载神经胶质瘤抗原DCs诱导的特异性CTL对患者自身神经胶质瘤细胞的杀伤率达88 17 % ,显著高于LAK细胞的杀伤率 (P<0 05)。且其对同种不同分化类型的神经胶质瘤细胞株 (P<0 01)。结论 :负载神经胶质瘤抗原的DCs体外可诱导出高效而特异的抗神经胶质瘤效应 ,提示以DCs为中心的肿瘤生物治疗作用可望提高神经胶质瘤综合治疗水平     

Biodegradable nanoparticle mediated antigen delivery to human cord blood derived dendritic cells for induction of primary T cell responses

Dendritic cells (DCs) in the peripheral tissues act as sentinels of the immune system. They detect and capture pathogens entering the body and present their antigens to T cells to trigger responses directed towards elimination of the pathogen. The induction of peripheral tolerance against self and certain foreign antigens is also believed to be mediated through DCs. The outcome of any immune response is largely controlled by the microenvironment of antigen capture, processing and presentation by DCs. The "context" of antigen delivery to DCs will directly influence the microenvironment of antigen presentation and hence the regulation of immune responses. We report here preliminary investigations describing the formulation of a pharmaceutically acceptable, biodegradable, and strategic nanoparticulate delivery system, and its application for efficient antigen loading of DCs to achieve antigen specific T cell activation. "Pathogen-mimicking" nanoparticles capable of interacting with DCs were fabricated by incorporating monophosphoryl lipid A (MPLA; toll-like receptor (TLR) 4 ligand) or CpG ODN (seq #2006; TLR9 ligand) in biodegradable copolymer, poly(D,L,-lactic-co-glycolic acid) (PLGA). The uptake of PLGA nanoparticles by human umbilical cord blood derived DCs (DCs propagated from CD34 progenitors) was conclusively demonstrated by scanning electron microscopy (SEM), fluorescence activated cell sorting (FACS) and confocal laser scanning microscopy (CLSM). Cell phenotype at day 12 of cultures was determined as immature DC using specific cell surface markers, i.e. CD11c (approximately 90%), MHC-II (approximately 70%), CD86 (approximately 20%), CD83 (approximately 5%), CD80 (approximately 40%), CD40 (approximately 40%), and CCR7 (approximately 5%). Tetanus toxoid (TT), a model antigen, was encapsulated in nanoparticles along with an immunomodulator, i.e. either MPLA or CpG ODN. DCs pulsed with various antigen formulations were co-cultured with autologous na?ve T cells at various cell ratios (DC: T cells were 1:5-20). The DCs pulsed with TT and MPLA together in nanoparticles induced significantly higher T cell proliferation (P<0.05) as compared to when DCs pulsed with TT and MPLA in solution were employed. A similar trend was observed when CpG ODN was used instead of MPLA in the TT nanoparticles. This strategy of antigen delivery to DCs was then tested with a cancer vaccine candidate, a MUC1 lipopeptide. The T cell proliferation observed in the presence of nanoparticulate MUC1 and MPLA pulsed-DCs was much higher than DCs pulsed with soluble antigen (P<0.0005). These results indicate that PLGA nanoparticles mimicking certain features of pathogens are efficient delivery systems for targeting vaccine antigens to DCs and activation of potent T cell responses.     

Biodegradable Nanoparticle Mediated Antigen Delivery to Human Cord Blood Derived Dendritic Cells for Induction of Primary T Cell Responses

Dendritic cells (DCs) in the peripheral tissues act as sentinels of the immune system. They detect and capture pathogens entering the body and present their antigens to T cells to trigger responses directed towards elimination of the pathogen. The induction of peripheral tolerance against self and certain foreign antigens is also believed to be mediated through DCs. The outcome of any immune response is largely controlled by the microenvironment of antigen capture, processing and presentation by DCs. The “context” of antigen delivery to DCs will directly influence the microenvironment of antigen presentation and hence the regulation of immune responses. We report here preliminary investigations describing the formulation of a pharmaceutically acceptable, biodegradable, and strategic nanoparticulate delivery system, and its application for efficient antigen loading of DCs to achieve antigen specific T cell activation. “Pathogen-mimicking” nanoparticles capable of interacting with DCs were fabricated by incorporating monophosphoryl lipid A (MPLA; toll-like receptor (TLR) 4 ligand) or CpG ODN (seq #2006; TLR9 ligand) in biodegradable copolymer, poly(_d,_l-lactic-co-glycolic acid) (PLGA). The uptake of PLGA nanoparticles by human umbilical cord blood derived DCs (DCs propagated from CD34₊ progenitors) was conclusively demonstrated by scanning electron microscopy (SEM), fluorescence activated cell sorting (FACS) and confocal laser scanning microscopy (CLSM). Cell phenotype at day 12 of cultures was determined as immature DC using specific cell surface markers, i.e. CD11c_hi (～90%), MHC-II₊ (～70%), CD86_low (～20%), CD83_low (～5%), CD80₊ (～40%), CD40₊ (～40%), and CCR7_low (～5%). Tetanus toxoid (TT), a model antigen, was encapsulated in nanoparticles along with an immunomodulator, i.e. either MPLA or CpG ODN. DCs pulsed with various antigen formulations were co-cultured with autologous naïve T cells at various cell ratios (DC: T cells were 1:5–20). The DCs pulsed with TT and MPLA together in nanoparticles induced significantly higher T cell proliferation (P<0.05) as compared to when DCs pulsed with TT and MPLA in solution were employed. A similar trend was observed when CpG ODN was used instead of MPLA in the TT nanoparticles. This strategy of antigen delivery to DCs was then tested with a cancer vaccine candidate, a MUC1 lipopeptide. The T cell proliferation observed in the presence of nanoparticulate MUC1 and MPLA pulsed-DCs was much higher than DCs pulsed with soluble antigen (P<0.0005). These results indicate that PLGA nanoparticles mimicking certain features of pathogens are efficient delivery systems for targeting vaccine antigens to DCs and activation of potent T cell responses.     

Apoptic renal carcinoma cells are better inducers of cross-presenting activity than their primary necrotic counterpart

Vaccination with tumor-loaded dendritic cells (DC) is a promising treatment strategy for patients with renal cell carcinoma (RCC). Cells undergoing cell death proved useful as a source of tumor antigen for DC loading. Both apoptotic and necrotic tumor cells have been shown to efficiently load RCC-tumor antigens on DC. However, no direct comparison of these two kinds of death has been attempted in the same RCC. We compared DC pulsed with apoptotic cells, whole cell lysates or their supernatants of the cell line K1, derived from a patient with clear cell RCC, to determine their ability to activate T cells. Monocyte-derived DCs were pulsed with the different sources of tumor antigen, matured and co-cultured with autologouos peripheral blood lymphocytes. After three weekly re-stimulations with DCs, generation of cytotoxic T lymphocytes CTL was assessed by IFN-gamma release in an ELISpot assay in the presence of the sensitizing target. By comparison with lysate, apoptotic tumor cells induced a higher frequency of MHC class I-restricted IFN-gamma releasing lymphocytes. A higher CTL response was induced by pulsing DCs with cell lysate supernatant compared with whole cell lysate. These results indicate that, although necrotic death has been regarded as highly permissive when compared to apoptotic death, the immunogenicity of the death treatment may vary from one tumor to another.     

Protective antitumor activity through dendritic cell immunization is mediated by NK cell as well as CTL activation

Dendritic cells (DCs) are potent professional antigen-presenting cells (APC) capable of inducing the primary T cell response to antigen. Although tumor cells express target antigens, they are incapable of stimulating a tumor-specific immune response due to a defect in the costimulatory signal that is required for optimal activation of T cells. In this work, we describe a new approach using tumor-DC coculture to improve the antigen presenting capacity of tumor cells, which does not require a source of tumor-associated antigen. Immunization of a weakly immunogenic and progressive tumor cocultured with bone marrow-derived DCs generated an effective tumor vaccine. Immunization with the cocultured DCs was able to induce complete protective immunity against tumor challenges and was effective for the induction of tumor-specific CTL (cytotoxic T lymphocyte) activity. Furthermore, high NK cell activity was observed in mice in which tumors were rejected. In addition, immunization with tumor-pulsed DCs induced delayed tumor growth, but not tumor eradication in tumor-bearing mice. Our results demonstrate that coculture of DCs with tumors generated antitumor immunity due to the NK cell activation as well as tumor-specific T cell. This approach would be useful for designing tumor vaccines using DCs when the information about tumor antigens is limited.     

Dendritic cell-tumor coculturing vaccine can induce antitumor immunity through both NK and CTL interaction

Immunization of dendritic cells (DC) pulsed with tumor antigen can activate tumor-specific cytotoxic T lymphocytes (CTL) that are responsible for protection and regression. We show here that immunization with bone marrow-derived DC cocultured with tumor cells can induce a protective immunity against challenges to viable tumor cells. In this study, we further investigated the mechanism by which the antitumor activity was induced. Immunization of mice with DC cocultured with murine colon carcinoma. CT-26 cells, augmented CTL activity against the tumor cells. Concomitantly, an increase in natural killer (NK) cell activity was also detected in the same mice. When DC were fixed with paraformaldehyde prior to coculturing with tumor cells, most of the CTL and NK cell activity diminished, indicating that DC are involved in the process of presenting the tumor antigen(s) to CTL. NK cell depletion in vivo produced markedly low tumor-specific CTL activity responsible for tumor prevention. In addition, RT-PCR analysis confirmed the high expression of INF-gamma mRNA in splenocytes after vaccination with DC cocultured with tumors, but low expression in splenocytes from NK-depleted mice. Most importantly, the tumor protective effect rendered to DC by the coculturing with CT-26 cells was not observed in NK-depleted mice, which suggests that DC can induce an antitumor immune response by enhancing NK cell-dependent CTL activation. Collectively, our results indicate that NK cells are required during the priming of cytotoxic T-cell response by DC-based tumor vaccine and seem to delineate a mechanism by which DC vaccine can provide the desired immunity.     

脐血浆培养的脐血树突状细胞对胃癌细胞的特异杀伤作用

目的尝试用脐血浆代替胎牛血清培养脐血树突状细胞（DCs）,并使之负载胃癌抗原,观察其对胃癌细胞的特异杀伤作用。方法分离脐血单个核细胞（CBMCs）并在含10％同源脐血浆的培养体系中诱导培养,部分细胞加入胃癌冻融抗原冲击。流式细胞仪检测细胞表面抗原CD1a和CD83表达,MTT法检测DCs体外刺激淋巴细胞增殖活性,LDH法检测DCs诱导的细胞毒T淋巴细胞（CTLs）对胃癌及肝癌细胞的细胞毒作用。结果CBMCs能分化为表型正常的未成熟DCs,并进而吞噬胃癌细胞冻融抗原成熟,刺激淋巴细胞增殖并诱导对胃癌细胞株特异的CTLs毒性。结论脐血浆培养的脐血DCs能有效捕获胃癌冻融抗原,激发针对胃癌细胞的特异杀伤效应。本实验采用的DCs制备方法具有方法简单、成本较低、瘤苗制备时间较短等优点。