热激胃癌细胞外泌体致敏DC诱导显著的抗肿瘤免疫反应

目的:探讨热激胃癌细胞来源外泌体致敏树突状细胞(dendritic cells,DCs)诱导的肿瘤特异性细胞毒T细胞(cytotoxic T lymphocyte,CTL)反应.方法:制备小鼠前胃癌细胞(murine foregastric cancer cells,MFC)来源外泌体(Exo)、热激MFC细胞来源外泌体(Exo/HS)及MFC细胞冻融抗原(lysates,Lys),通过电镜观察外泌体的形态,Western blotting检测外泌体的成分.培养小鼠骨髓来源的DCs,将Exo/HS、Exo和Lys冲击致敏DCs,制备的DCs瘤苗分别命名为DC-Exo/HS、DC-Exo和DC-Lys.HSP70小干扰RNA(small interference RNA,siRNA)转染MFC细胞,热激后分离上清,用制备外泌体致敏DCs,流式术检测DCs的表型.以DC-Exo/HS、DC-Exo、DC-Lys、DC和PBS免疫小鼠,3H-TdR法检测脾脏T细胞的增殖,LDH法检测脾细胞CTL活性.建立MFC细胞荷瘤小鼠模型,观察各组DCs瘤苗的免疫治疗效应.结果:电镜确认外泌体为膜性小囊泡.Western blotting检测表明,Exo/HS含有高水平的HSP70,流式术发现热激MFC细胞来源外泌体能显著上调DCs表面MHC-Ⅱ、CD80、CD86和CD40分子的表达,HSP70 siRNA干扰能下调热激MFC细胞来源外泌体刺激的DCs表面MHC-Ⅱ、CD80、CD86和CD40分子的表达.3H-TdR检测结果显示DC-Exo/HS刺激T细胞增殖的能力显著强于DC-Exo、DC-Lys、DC和PBS组(均P＜0.01),LDH检测结果表明DC-Exo/HS诱导的CTL活性显著高于DC-Exo、DC-Lys、DC和PBS组(均P＜0.01),HSP70 siRNA组诱导的CTL活性显著低于对照siRNA组(P＜0.01).免疫治疗结果显示,DC-Exo/HS对荷瘤小鼠的肿瘤抑制效应显著优于其他各组(P＜0.01).结论:热激胃癌细胞来源外泌体致敏的DCs能诱导显著的抗肿瘤免疫反应.     

不同方式负载AFP抗原的DC诱导抗肝癌HepG2细胞免疫效应的比较

目的：比较AFP抗原以不同方式负载DCs对后者生物学功能的影响及体外刺激CTL对肝癌HepG2细胞的杀伤作用。方法：分离健康供者外周血单个核细胞培养DC,分别用（A）人工合成AFP抗原肽、（B）HepG2细胞裂解物、（C）HepG2细胞分泌的外泌体（tumor exosome, T-exo）、（D）AFP抗原的重组腺相关病毒（recombinant adeno-associated virus expressing α-fetoprotein antigen, rAAV/AFP）致敏DC前体细胞及（E）未负载抗原的DC作为对照,经GM-CSF、IL-4及LPS联合诱导DCs分化成熟。流式细胞术检测rAAV/AFP病毒感染效率、各组DCs表型及其剌激初始T细胞的增殖效应,7-ADD/CFSE双染法流式细胞术检测各组DCs诱导CTL对AFP阳性HepG2细胞的杀伤作用。结果：几种抗原负载方式均可诱导DCs成熟、促进CTL增殖及特异性识别并杀伤HepG2细胞,但rAAV/AFP感染DCs后,其CD83、CD86、ICAM-1、CD58、CD40分子表达水平明显高于对照组（P<0.05）,rAAV/AFP+DC组和HepG2-Texo+DC组对HepG2细胞的杀伤作用均分别显著优于其他抗原负载（AFP/peptide+DC、HepG2 lysate+DC）组\[（44.92±4.12）% vs（28.42±3.29）%、（24.28±1.79)%;（41.40±2.87）% vs （28.42±3.29）%、（24.28±1.79）%;均P<0.05）\]。结论：rAAV/AFP高效感染DCs后能有效刺激初始T细胞增殖,并增强CTL对AFP阳性靶细胞的杀伤活性,而负载Texo的DCs也能诱导显著的抗肝癌效应,上述结果为基于DCs的肝癌疫苗的研发提供新的思路。     

甲醛对HepG2细胞游离胆固醇代谢的影响

目的：研究甲醛（FA）对人肝癌细胞株HepG2细胞游离胆固醇（FC）含量的影响及其作用机制。方法：分别采用0.004、0.02、0.1 mmol/L FA处理人肝癌细胞株HepG2细胞24和48 h,以完全培养基为阴性对照,过氧化物酶法测定HepG2细胞内FC含量;采用Western blot法检测HepG2细胞固醇调节元件结合蛋白-2（SREBP-2）、羟甲基戊二酸单酰辅酶A还原酶（HMGCR）、胆固醇酰基转移酶（ACAT）和低密度脂蛋白受体（LDLR）的蛋白表达水平。结果：与阴性对照组相比,各浓度的FA染毒24 h或0.02和0.1 mmol/L FA染毒48 h后,HepG2细胞内FC含量均明显增加（P均 < 0.05）;FA染毒24和48 h后细胞内HMGCR蛋白表达水平均明显增加（P < 0.05）;FA染毒24 h后,ACAT和LDLR表达水平均明显降低（P均 < 0.05）;FA染毒48 h,LDLR蛋白表达水平明显降低（P < 0.05）,ACAT蛋白表达水平在0.02和0.1 mmol/L FA组明显降低（P < 0.05）。结论：甲醛染毒可使HepG2细胞内FC含量增加,可能与胆固醇的从头合成增加和胆固醇酯化水平降低有关。     

癌源性外泌体对乳腺癌MCF-7细胞生物学行为的影响

目的 探究乳腺癌细胞来源的外泌体对乳腺癌MCF-7细胞生物学行为的影响。方法 使用超速离心法对人乳腺癌MCF-7细胞培养液中的外泌体进行提取和纯化,通过透射电子显微镜观察外泌体的形态和大小,Western blot实验鉴定外泌体的标志蛋白。以外泌体与MCF-7细胞共培养48 h后的细胞为实验组,以未处理的MCF-7细胞为对照组。用MTT法、克隆形成实验、细胞划痕实验、细胞侵袭实验、流式细胞术实验和Western blot实验检测乳腺癌源性外泌体对MCF-7细胞增殖、克隆形成、迁移、侵袭、凋亡及上皮-间充质转化(Epithelial-mesenchymal transition,EMT)能力的影响。结果 透射电子显微镜下外泌体的形状为典型的杯托状或者凹的半球状结构,直径40~110 nm;Western blot实验结果显示外泌体标志性蛋白CD9及CD81均明显表达;MTT和克隆形成实验结果显示,实验组细胞增殖及克隆形成能力较对照组明显增强(P＜0.05);划痕实验和侵袭实验结果显示,与对照组相比,实验组细胞迁移及侵袭能力明显增强(P＜0.001);流式细胞术分析显示,在外泌体刺激的乳腺癌细胞中,凋亡细胞的百分比显著低于对照组(P＜0.05);Western blot结果显示,乳腺癌来源的外泌体增加了N-cadherin和Vimentin的表达,降低了E-cadherin表达,促进了乳腺癌EMT过程(P＜0.05)。结论 乳腺癌细胞来源的外泌体能增强肿瘤细胞的细胞增殖、克隆形成、迁移和侵袭能力,促进乳腺癌EMT过程,并抑制肿瘤细胞凋亡。表明肿瘤来源外泌体可能作为细胞间信号转导的介质,在促进肿瘤生长和转移的信息传递方面发挥重要作用。     

漆姑草醇提物对白血病细胞K562的诱导分化作用

目的： 研究漆姑草醇提物（HSJ）对人慢性髓系白血病细胞（K562）的诱导分化作用。方法： 实验设HSJ不同浓度（250、125、62.5 μg/mL）实验组,阴性对照组（等体积1640培养基）,作用48 h后,采用四甲基噻唑蓝（MTT）法检测K562细胞增殖抑制率;瑞氏-吉姆萨染色观察K562细胞形态;硝基四氮唑蓝（NBT）还原实验法测定K562细胞分化能力;流式细胞术检测K562细胞分化相关抗原CD11b、CD14、CD41a和CD42b阳性细胞的表达率;Western blot法检测K562细胞中珠蛋白转录因子1（GATA1）和造血转录因子1（PU.1）蛋白的表达。结果： 与阴性对照组比较,各浓度HSJ均能有效抑制K562细胞的增殖（P < 0.05）;经HSJ作用后,各实验组K562细胞核浆比例减小,出现分叶状细胞核,部分细胞核凹陷出现明显的细胞分化形态;与阴性对照组相比,3个不同浓度HSJ组的NBT还原率均提高（P < 0.05）;CD11b、CD14、CD41a和CD42b阳性细胞表达率均增加（P < 0.05）;GATA1和PU.1蛋白相对含量亦增加,差异均具有统计学意义（P < 0.05）。结论： 漆姑草醇提物能诱导K562细胞向成熟细胞方向分化。     

氯喹通过激活P38MAPK通路诱导人肝癌HepG2细胞凋亡

目的：研究氯喹对人肝癌HepG2细胞增殖和凋亡的影响,并初步研究其可能的机制。方法：体外培养HepG2细胞,采用MTT法检测不同浓度（0、10、20和40 μmol/L）氯喹作用不同时间（24、48和72 h）后对细胞增殖的影响;用DAPI染色观察氯喹处理细胞24 h后细胞核的变化;流式细胞术检测氯喹对HepG2细胞凋亡的影响;Western blot技术检测氯喹对HepG2细胞中Caspase-3、Bcl-2、Bax、P-P53、P38MAPK和P-P38MAPK蛋白表达的影响。结果：与对照组比较,在上述3个时间点10、20、40 μmol/L氯喹（10 μmol/L氯喹作用24 h组除外）对人肝癌HepG2细胞的增殖均有明显抑制作用（P均 < 0.05）;荧光显微镜下发现,10、20、40 μmol/L氯喹处理24 h后均可引起HepG2细胞不同程度的核浓集、固缩等典型凋亡形态变化;流式细胞术结果提示10、20、40 μmol/L氯喹能诱导HepG2细胞凋亡（P均 < 0.05）;Western blot结果显示20和40 μmol/L氯喹作用HepG2细胞后,P-P53、P-P38MAPK、剪切后活化型Caspase-3和Bax蛋白表达量增加（P均 < 0.05）,Bcl-2表达下降,Caspase-3和P38MAPK表达无明显变化（P > 0.05）。结论：氯喹能够抑制人肝癌HepG2细胞的生长并诱导其凋亡,其机制可能与P38MAPK通路有关。     

QHF复方对人肝癌Huh7细胞生长、侵袭及肿瘤干细胞表面标志物表达的影响

目的：研究中药QHF复方对人肝癌Huh7细胞生长、凋亡和侵袭能力的作用,并初步研究其对肿瘤干细胞表面标志物表达的影响。方法：体外培养人肝癌Huh7细胞,MTT法检测QHF复方对细胞增殖的影响;流式细胞术检测QHF复方对Huh7细胞周期及凋亡的影响;Transwell实验检测QHF复方对Huh7细胞侵袭能力的影响;流式细胞仪检测QHF复方作用后Huh7细胞肿瘤干细胞表面标志物CD133和CD44的表达情况。结果：与溶剂对照组比较,QHF复方能够抑制Huh7细胞增殖,并且这种抑制作用具有剂量和时间依赖性（P均 < 0.05）;QHF复方能诱导细胞凋亡,使其生长周期阻滞在S期;QHF复方能够降低Huh7细胞的侵袭能力（P < 0.05）;并能够下调肿瘤干细胞表面标记物CD133和CD44的表达（P < 0.05）。结论：中药QHF复方能够抑制Huh7细胞的生长、侵袭,这种抑制作用可能与肿瘤干细胞表面标记物CD133和CD44表达的下调有关。     

rhHSP70联合冻融抗原修饰树突状细胞诱导的抗乳腺癌作用

  目的   利用rhHSP70联合树突状细胞递呈肿瘤抗原的特性提高细胞毒T淋巴细胞（CTLs）对乳腺癌细胞的杀伤活性。   方法   外周血单个核细胞体外经GM-CSF和IL-4诱导产生树突状细胞,负载冻融抗原肽的同时加入新型热休克蛋白（rhHSP70）,不同分组分别诱导自体CTLs产生。ELISA测定CTLs杀伤活性和细胞因子的分泌。   结果   冻融抗原肽致敏的DCs促进CTLs增殖,上调CTLs中CD3+和CD8+T细胞群及Th1型细胞因子的分泌;体外实验中具有对人乳腺癌细胞MCF-7的杀伤活性,在加入rhHSP70后效果更加明显,并能显著增强CTLs对肿瘤细胞的杀伤率。   结论   hHSP70联合肝癌冻融抗原修饰DCs,能够促进DCs的成熟,增强DCs刺激淋巴细胞增殖的能力,诱导的CTLs在体外对乳腺癌细胞能产生高效杀伤力。rhHSP70增强DCs抗肿瘤能力的机制可能与其促进DCs成熟有关。       

漆姑草醇提物对人急性早幼粒白血病细胞的诱导分化作用

目的： 探讨漆姑草醇提物（HSJ）对人急性早幼粒白血病细胞（NB4）的诱导分化作用。方法： 以NB4细胞为研究对象,设HSJ低（30 μg/mL）、中（60 μg/mL）、高（120 μg/mL）剂量组和阴性对照组,共4组;HSJ作用NB4细胞48 h后,采用透射电镜法观察NB4细胞形态;硝基四唑氮（NBT）还原实验检测NB4细胞分化能力;流式细胞术检测NB4细胞周期分布;流式细胞术检测NB4细胞表面分化抗原CD14和CD11b细胞的表达率;实时荧光定量PCR （qPCR）检测c-fos mRNA表达;Western blot检测c-fos蛋白表达。结果： 与对照组比较,3个不同剂量HSJ处理组NB4细胞胞核均缩小,胞浆呈空泡状,核形呈肾形或蚕豆形;各HSJ处理组NB4细胞的NBT还原率均高于对照组,差异有统计学意义（P < 0.05）;HSJ处理组NB4细胞中G2期细胞比例均高于对照组,而S期细胞比例均低于对照组,差异有统计学意义（P < 0.05）;HSJ处理组CD14和CD11b阳性细胞表达率均高于对照组（P < 0.05）;HSJ低剂量组cfos mRNA和蛋白表达与对照组比较,差异均无统计学意义（P > 0.05）,HSJ中、高剂量组c-fos mRNA和蛋白表达均高于对照组,差异均有统计学意义（P < 0.05）。结论： HSJ可能诱导NB4细胞向成熟粒细胞方向分化。     

肿瘤外泌体对CD8+T细胞功能的影响及机制研究进展

外泌体（exosomes）是介导细胞间通讯的细胞外囊泡。它携带来源细胞的多种生物活性分子,并可将其输送给受体细胞,进而影响细胞功能。肿瘤来源外泌体可通过多种机制介导肿瘤的免疫逃逸。本文就肿瘤外泌体对肿瘤杀伤主力军CD8+T细胞的调控作用进行总结,分析其相关作用机制,以期为肿瘤免疫治疗的研发提供新的思路。     

HSP70-Id复合物修饰的树突状细胞体外诱导特异性抗肿瘤作用

目的观察人慢性B淋巴细胞性白血病（B-CLL）细胞的独特型抗原Id-ScFv与热休克蛋白70（HSP70）形成复合物修饰的树突状细胞（DC）体外诱导特异性抗肿瘤作用,并初步探讨其机制。方法将HSP70与Id-ScFv体外结合形成复合物HSP70-Id,修饰自人外周血单核细胞获取的DC。倒置相差显微镜观察DC的形态特征;流式细胞仪检测修饰前后DC的表型变化,酶联免疫吸咐试验（ELISA）检测DC分泌的白细胞介素12（IL-12）和肿瘤坏死因子-α（TNF-α）,四甲基偶氮唑蓝（MTT）法检测修饰的DC对自身淋巴细胞的激活和增殖作用,流式细胞仪检测激活的自身淋巴细胞T细胞亚群的变化,台盼蓝染色法检测其对Daudi、K562和HepG2等细胞的杀伤作用。结果DC体外诱导培养成功,HSP70-Id复合物可使DC成熟,镜下可见典型的DC形态,其CD1a表达率为20％-30％,CD83表达率〉72％,CD86和HLA-DR表达显著增加（P〈0．05）,上清中IL-12、TNF-α亦显著高于DC对照组（P〈0．01）。HSP70-Id复合物修饰的DC激活自身淋巴细胞,对Daudi细胞的杀伤率为71．24％,而对K562细胞杀伤作用较弱,对HepG2细胞无明显作用。其淋巴细胞亚群中,CD4^＋T细胞、CD8^＋T细胞的比例均显著增加,分别为56．51％和70．21％,CD4^＋T细胞／CD8^＋T细胞比值由空白对照组的1．49倒置为0．81。结论HSP70-Id复合物修饰的DC生物学活性增强,经其刺激后,传代培养的淋巴细胞可产生高效而特异性的抗肿瘤免疫效应,可能是CD4^＋T细胞、CD8^＋T细胞及DC协同作用的结果。     

Hyperthermia improves cellular immune response to human hepatocellular carcinoma subsequent to co-culture with tumor lysate pulsed dendritic cells

Dendritic cells play a major role in cellular immunity. The crucial steps of antigen presentation and processing by DCs may be limiting factors for adoptive cellular immunotherapy. Here, we investigated whether hyperthermia of human hepatocellular carcinoma (HCC) cells induces enhanced cytotoxic cellular immune response. Peripheral blood mononuclear cell (PBMC)-derived DCs were pulsed with tumor cell lysate of the human HCC cell line HepG2, which had been heat shocked prior to incubation for 5 h. Subsequent to TNFalpha-induced maturation DCs were co-cultured with autologous CD4+ and/or CD8+ cells, and T cell mediated cytolysis of HepG2 cells was assessed. We observed enhanced CD4+/8+ cellular cytotoxicity against HepG2 cells subsequent to co-culture with the heat shocked tumor lysate pulsed DCs as compared to pulsing DCs with lysate of non-heat shocked tumor cells. The improved cellular immune response can be related to enhanced expression of HSP 70 and 90 in HepG2 cells upon hyperthermia.     

抑制SOCS1联合OK-432刺激的DC疫苗抗肿瘤效应的初步研究

BACKGROUND & OBJECTIVE: Suppressor of cytokine signaling 1 (SOCS1) plays a critical role in antitumor immunity. Down-regulating SOCS1 in antigen-presenting dendritic cells (DCs) could enhance antigen-specific antitumor immunity. This study was to investigate the antigen-specific antitumor effect and mechanism of DCs with siRNA-mediated inhibition of SOCS1, stimulated by OK-432 and pulsed with hepatocellular carcinoma cell line HepG2 antigens. METHODS: The expression of SOCS1 in immature DCs was down-regulated by RNA interference (RNAi). DCs were pulsed with lysate of HepG2 cells and stimulated with OK-432. The morphology of DCs was observed under converted phase microscopy. Phenotypic changes in cells after stimulation were characterized by flow cytometry (FCM). The Alamar Blue assay was adopted to evaluate the activation and proliferation of autologous lymphocytes induced by mature DCs. The cytotoxicity of cytotoxic T lymphocytes (CTLs) elicited by modified DCs to HepG2, EC109 and K562 cells was tested by the lactate dehydrogenase (LDH) assay. RESULTS: Cells displaying a typical morphology and phenotypic properties of mature DCs were obtained successfully. The expression of SOCS1 in DCs was down-regulated by SOCS1 RNAi. Mature DCs showed high expressions of CD80, CD83, CD86, and HLA-DR. Pulsing of DCs with lysate of HepG2 had no influence on the phenotypic properties of DCs. Down-regulating SOCS1 expression enhanced the maturation of DCs. The modified DC tumor vaccine stimulated the proliferation of autologous lymphocytes effectively, and the proliferation rate of T cells was (110.7+/-22.2)%. After being activated by modified DCs, TCLs exerted a specific and effective killing effect on HepG2 cells, but not on EC109 and K562 cells. CONCLUSION: Mature DCs could induce antigen-specific antitumor immunity against hepatocellular carcinoma after silencing of SOCS1 by siRNA, stimulation by OK-432 and pulsing of DCs with HepG2 cell antigens.     

树突状细胞负载的exosome疫苗抗胶质瘤的实验研究

目的：旨在分离胶质瘤细胞释放的exosomes,致敏外周血树突状细胞（dendritic cell,DCs）,观察其对细胞毒性T淋巴细胞（cytotoxic T lymphocytes,CTLs）的激活效应。方法：离心超滤和蔗糖密度梯度离心法分离胶质瘤细胞释放的exosomes,固相免疫电镜法（SPIEM）制备exosomes的MAGE-1及ICAM-1免疫电镜标本。常规方法从外周血单个核细胞诱导DCs并分离T细胞,将胶质瘤细胞来源的exosomes冲击或未冲击的DCs与T细胞共培养。MTT比色法检测体外细胞毒活性。结果：胶质瘤细胞分泌的exosomes为直径50-100nm的膜性微囊,经抗MAGE-1、ICAM-1抗体-胶体金免疫电镜标记,囊外膜可见点状？颗粒状电子致密物沉积。培养后DCs的表面标志物CD1a、HLA-DR、CD83、CD86的表达率较培养前明显升高,差异有显著性（P〈0.05）。exosomes致敏的外周血DCs激活CTLs的能力显著高于肿瘤冻融抗原致敏的DCs组,在效靶比为50：1时,两组CTLs对胶质瘤细胞的杀伤率为70.4%±4.1%vs30.1%±2.8%,（P〈0.05）。结论：胶质瘤细胞分泌的exosomes负载外周血DCs后活化CTLs,发挥抗肿瘤活性,可以作为一种有效的抗胶质瘤免疫治疗策略和方法。     

凋亡肿瘤细胞致敏的树突状细胞疫苗治疗肺癌的实验研究

目的：用凋亡肿瘤细胞致敏的树突状细胞（dendritic cells，DCs）激发肿瘤抗原特异性的细胞毒T细胞（cytotoxic T lymphocytes，CTL）活性，观察其体内外抗肺癌的特性。方法：常规方法从健康人外周血单个核细胞中诱导DCs，采用或不采用凋亡肿瘤细胞负载DCs，并利用激发型CD40单克隆抗体（CD40mAb）诱导DCs成熟；成熟DCs与自体T细胞共育，分别获得Ag-CTL及non-Ag-CTL，流式细胞仪检测Ag-CTL细胞表型的变化；^3H-TdR掺入法测定DNA片段形成率；建立人肺癌细胞株A549荷瘤裸鼠模型，过继回输Ag-CTL和non-Ag-CTL，评价其在体内的抗肿瘤活性。结果：CD40mAb激发可使DCs上调CD1a、CD80、CD86、CD83、HLR-DR的表达；凋亡肿瘤细胞负载联合CD40mAb激发可进一步促进DCs的成熟；成熟DCs和自体的T细胞共育活化后CD8^＋T细胞明显上调；Ag—CTL对A549具有高效特异的杀伤力，明显强干Ag-CTL对肝癌细胞株HepG2的作用（P〈0．01），且Ag-CTL对A549的杀伤力明显强于non—Ag-CTL（P〈0．01），而non-Ag-CTL对A549及HepG2细胞的杀伤力无显著性差异；体内实验表明，Ag-CTL可有效抑制裸鼠皮下移植瘤的生长，与生理盐水组（NS组）、non-Ag-CTL组相比在统计学意义上有显著差异（P〈0．05），non-Ag-CTL组与NS组相比在统计学意义上有差异（P〈0．05）。结论：凋亡肿瘤细胞致敏的树突状细胞疫苗激发的Ag—CTL在体内外均呈现抑制肺癌细胞的特性。     

自体宫颈癌-树突细胞疫苗激活的CTL杀伤效应

背景与目的:树突细胞(dendriticcells,DC)是目前已知的功能最强的抗原递呈细胞(antigen-presentingcell,APC),它可以在体内、外向T淋巴细胞递呈抗原,并诱发细胞毒T淋巴细胞(cytotoxicTlymphocyte,CTL)反应。本研究旨在探讨负载自体宫颈癌抗原的DC体外激发的CTL对自体宫颈癌细胞的杀伤效应。方法:先冻融宫颈癌细胞制备抗原,然后以GM-CSF、IL-4诱导自体外周血单个核细胞(peripheralbloodmononuclearcell,PBMC)获得DC并负载抗原,刺激自体T淋巴细胞制备宫颈癌抗原特异性CTL,观察CTL对宫颈癌细胞的杀伤活性。结果:负载自体宫颈癌抗原DC诱导的特异性CTL对自体宫颈癌细胞的体外杀伤率高达79.32%～89.27%,显著高于淋巴因子激活的杀伤细胞(lymphokine-activatedkillingcells,LAK)的杀伤率(t≥2.89,P<0.05);且对宫颈癌HeLa细胞株具有一定杀伤效应(40.35%～58.09%),但低于自体癌细胞组(t≥2.97,P<0.05);特异性CTL对HepG2、MCF7、A549、MGC803细胞无明显杀伤效应。结论:自体宫颈癌-树突细胞疫苗体外诱导的CTL具有高效而特异的抗自体宫颈癌细胞免疫活性,可望成为宫颈癌生物治疗的一个有力手段。     

RNA-electroporated CD40-activated B cells induce functional T-cell responses against HepG2 cells

Hepatocellular carcinoma (HCC) is one of the incurable tumours in the world. Cell-based immunotherapy, in which antigen-loaded antigen-presenting cells (APCs) are able to elicit T cell responses, has become an alternative treatment for liver cancer. Here, we used HepG2 cells' total RNA-electroporated CD40 ligand-activated B (CD40-B) cells as alternative APC for induction of specific CD8⁺ T-cell responses. The antigen-presenting ability of CD40-B cells was determined by phenotypic analysis, showing a polyclonal, strongly activated B-cell population with high expression of co-stimulatory molecules. To demonstrate the ability of total RNA extracted from HepG2 cells electroporated CD40-B cells to induce CD8⁺ T-cell responses, these RNA-loaded cells were co-cultured with autologous peripheral blood mononuclear cells for 7 days followed by analysis of T-cell antigen specificity. These experiments showed that CD40-B cells electroporated with HepG2 cells' total RNA are capable of activating antigen-specific interferon-γ-producing CD8⁺ T cells, and these T cells activated by CD40-B cells show a killing effect on HepG2 cells. These findings demonstrated that the carcinoma cell derived total RNA-electroporated CD40-B cells could be used as alternative APC for the induction of antigen-specific CD8⁺ T-cell responses, which might be used in HCC immunotherapy.     

Exosome-loaded dendritic cells elicit tumor-specific CD8<Superscript>+</Superscript> cytotoxic T cells in patients with glioma

In this study, we demonstrate that tumor-derived exosome-loaded dendritic cells can elicit a specific CD8⁺ cytotoxic T-lymphocyte (CTL) response against autologous tumor cells in patients with malignant glioma. Exosomes were purified by ultrafiltration centrifugation and sucrose gradient ultracentrifugation. Exosomes had antigen-presenting molecules (MHC-I, HSP70), tumor antigen (MAGE-1) and adherent molecule (ICAM-1). After incubation with exosomes, the dendritic cells (DCs) could activate the T lymphocytes to become glioma-specialized CTL. The CTL had vigorous cytotoxicity to glioma cells as opposed to autologous lymphoblast cells. These data demonstrate that tumor exosome-loaded DC can be an effective tool in inducing glioma-specific CD8⁺ CTLs able to kill autologous glioma cells in vitro. In conclusion, exosomes are a natural and new source of tumor-rejection antigens, opening up new avenues for immunization against glioma.     

Biological Response Modifiers Render Tumor Cells Susceptible to Autologous Effector Mechanisms by Influencing Adhesion Receptors

Adhesion molecules such as CD2 and its ligand CD58 (LFA-3), as well as CD1 la/18 (LFA-1) and CD54 (ICAM-1) regulate not only cell to cell attachment but also participate in lymphocyte activation, recirculation, and effector function including cytolytic activity towards tumor cells. We have investigated the role of CD2/CD58 and CDlla/18/CD54 interactions in cellular immune responses directed towards freshly recovered human T cell leukemias. Downregulation of CD54 and CD58 were observed to correlate with enhanced numbers of blasts in circulation and lack of susceptibility to killing by autologous cytotoxic lymphocytes. Furthermore, culturing tumor cells with recombinant TNF-alpha conditioned medium resulted in reinduction of CD54 and CD58 expression and susceptibility to lymphocyte mediated lysis in vitro. Our findings support the view that adhesion molecules play a pivotal role for tumor cell biology in vivo and stress the point that successful immunotherapy of malignant disease may be facilitated by influencing not only the immune response itself but also adhesion molecules on the malignant tumor targets.