Lgr5蛋白激活树突状细胞诱导抗原特异性细胞毒T淋巴细胞治疗结肠癌的实验

目的 探讨富含亮氨酸重复序列的G蛋白耦联受体5(Lgr5）蛋白激活树突状细胞(DCs),诱导产生CD8+ 细胞毒T淋巴细胞（CTL）进行结肠癌免疫治疗的效果。 方法 利用Lgr5蛋白诱导DCs成熟,同时检测DCs表面标记物和白细胞介素（IL)-10与IL-12表达量的变化,随后通过Lgr5-DC诱导Lgr5抗原特异性CD8⁺ CTL,并检测Lgr5-DC-CD8⁺ CTL对正常结肠上皮细胞CCD-18Co和结肠癌细胞HT29的作用,同时检测干扰素（IFN）-γ释放量。然后进一步检测Lgr5-DC-CD8⁺ CTL对BALB/C-nu/nu小鼠结肠癌的抑制情况,并通过组织染色观察治疗后肿瘤组织的变化。 结果 与PBS刺激相比,Lgr5蛋白刺激能够显著上调DCs表面标记物DC80、DC83、DC86和HLA-DR水平,依次达到3.29、3.06、2.90和6.93倍;同时Lgr5蛋白刺激显著促进IL-12的释放和显著减少IL-10的分泌(P＜0.05)。Lgr5-DC-CD8⁺ CTL和DC-CD8⁺ CTL均导致少量CCD-18Co细胞杀伤(P＞0.05), 而Lgr5-DC-CD8⁺ CTL对HT29细胞的杀伤率是DC-CD8+ CTL的4.40倍(P＜0.05)。动物实验表明,BALB/C-nu/nu结肠癌移植鼠经Lgr5-DC-CD8⁺ CTL治疗后,肿瘤体积比显著低于PBS组和DC-CD8⁺ CTL组,依次达到0.25和0.24倍(P＜0.05)。组织染色显示 Lgr5-DC-CD8⁺CTL处理导致明显的肿瘤组织病理学改变,同时BAX表达升高。 结论 Lgr5蛋白促进DCs成熟并诱导产生Lgr5抗原特异性CD8⁺ CTL,Lgr5-DC-CD8⁺ CTL能够高效的杀伤肿瘤细胞并延迟肿瘤生长。     

EB病毒LMP2A特异性CTL的体外诱导及分析

用EBV LMP2A重组痘苗病毒 (rVV LMP2A )转染人树突状细胞 (DC ) ,转染后的DC分别在第 1、 7、 14天刺激相同MHC背景的T细胞 ,在IL 2作用下诱导LMP2A特异性CTL。用LDH释放法检测CTL杀伤活性 ;流式细胞术 (FACS )检测CTL诱导分化过程中CD3+ 、CD4 + 、CD8+ 、CD5 6 + 等细胞的分群变化 ;RT PCR检测细胞分化过程中FasLmRNA表达 ;生物活性法检测功能性细胞因子IFN γ的分泌。结果显示本法诱导的CTL对靶细胞有特异性杀伤活性 ,第 2次和第 3次DC刺激后杀伤活性有所上升 ;在CTL诱导分化的第 7、 14、 2 1天细胞分群以CD4 + 、CD8+ 细胞为主 ;RT PCR证实所诱导的细胞内有FasLmRNA的表达 ;随细胞培养天数的增加IFN γ分泌增加 ,在第 14天达到较高水平。研究表明重组痘苗病毒载体rVV LMP2A转染的DC刺激T细胞可诱导出EBV LMP2A特异性CTL。     

冻融抗原负载树突状细胞诱导细胞毒性T淋巴细胞特异性杀伤急性白血病细胞的实验研究

我们应用基因重组人白介素 4 (rhIL 4 ) ,基因重组人粒 /单细胞集落刺激因子 (rhGM CSF)联合培养体系自健康志愿者骨髓单个核细胞诱导产生DC ,使其负载急性髓系白血病 (AML)细胞冻融抗原 ,体外诱导细胞毒性T细胞 (CTL) ,观察负载AML细胞冻融抗原后DC的状态对所激发的T淋巴细胞表型及功能的影响及CTL对AML细胞特异性杀伤活性。我们发现负载AML冻融抗原后DC的CD1a、CD83、CD86、CD11C、HLA DR表达率为较培养前明显增高 (P <0 .0 1) ,且负载AML冻融抗原的DC诱导的CTL中CD3 CD8 T细胞比例 ,较诱导前明显增高 (P <0 .0 1) ,而负载AML细胞冻融抗原的DC诱导CTL对AML细胞有较强的杀伤作用 ,明显强于加或不加IL 2培养的T细胞对照组 (P <0 .0 1) ,而对K5 6 2细胞无明显的杀伤活性。通过以上实验我们认为经rhGM CSF ,rhIL 4培养产生的DC为CD14CD1a DC ,能诱导CTL对AML细胞产生明显的特异性杀伤作用 ,另外 ,负载AML细胞冻融抗原DC诱导的CTL中CD3 CD8 T细胞比例明显增高 ,提示CD8 T细胞在抗肿瘤免疫中具有极其重要的作用。     

卵巢癌细胞株冻融抗原负载的树突状细胞诱导CTL抗卵巢癌免疫应答的体外研究

目的研究卵巢癌冻融抗原负载的树突状细胞(dendriticcells,DC)诱导细胞毒性T淋巴细胞(CTL)体外杀伤卵巢癌细胞的细胞毒性效应。方法利用免疫磁珠分离法(MACS)分离纯化脐血CD34 细胞并在体外诱导分化为DC,用反复冻融法从卵巢癌细胞系SKOV3中提取的可溶性相关抗原负载DC。流式细胞学检测负载抗原后DC表面各种分化相关抗原的表达,ELISA法检测DC上清中IL12的表达,混合淋巴细胞反应(MLR)测定DC体外刺激T细胞增殖的能力,MTT法检测抗原负载DC激活的抗原特异性CTL对卵巢癌细胞的杀伤作用。结果与未经抗原负载的DC相比,经卵巢癌抗原负载的DC不仅能更高地表达各种DC分化相关抗原CD1α(73.35%±2.94%vs34.1%±2.35%)、CD83(73.9%±8.46%vs54.68%±3.26%)、CD80(91.95%±2.48%vs52.53%±3.18%)、HLADR(70.05%±2.35%vs48.7%±2.07%)以及CD54(88.9%±5.52%vs71.45%±2.29%),同时具有更强的刺激同种异体T淋巴细胞增殖和IL12分泌的能力(P均<0.05)。此外,卵巢癌细胞SKOV3冻融抗原负载DC激活的CTL在体外对SKOV3的杀伤率为77.35%,显著高于未经抗原负载的DC(P=0.0001)。结论经卵巢癌细胞冻融抗原负载DC激活的CTL在体外具有更强的增殖能力和杀伤卵巢癌细胞的作用。     

IL-18基因修饰增强肿瘤抗原多肽致敏的树突状细胞体内诱导的抗肿瘤免疫反应

目的 :研究肿瘤抗原多肽致敏的白细胞介素 18(IL 18)基因修饰的树突状细胞体内诱导的抗肿瘤免疫反应。方法 :①以Lewis 3LL肺癌细胞特异性抗原肽mut1冲击致敏IL 18基因修饰的骨髓来源的树突状细胞 (DC IL 18 mut1) ,每次用其 1× 10 5 只皮下免疫小鼠 2次 ,然后测定脾细胞的NK活性及CTL杀伤活性 ;②以DC IL 18 mut1每次 2× 10 5 只皮下免疫 1次 ,然后再以 5× 10 53LL细胞攻击 ,在诱导及效应阶段分别以单抗阻断不同免疫成份 ,观察肿瘤的生长。结果 :以DC IL 18 mut1皮下免疫后可诱导出比DC mut1等免疫组更高水平的 3LL肺癌细胞特异性CTL ,并使NK活性明显增加 ;单抗体内阻断实验提示在DC IL 18 mut1免疫诱导阶段 ,CD4 + T细胞和抗原共刺激分子、IFN γ均起到重要作用 ,而效应阶段CD8+ T、IFN γ、NK起作用 ,而CD4 + T则是非必需的。结论 :DC IL 18 mut1皮下免疫后可诱导高水平的抗肿瘤免疫活性 ,其机理与抗原有效提呈、特异性CTL诱导、NK活性增加以及CD4 + 、CD8+ T、NK细胞、IFN γ参与密切相关。     

HBsAg体外冲击的慢性乙肝患者树突状细胞的生物学特性及其对HBV特异性CTL的诱导作用

目的 :研究HBsAg冲击的慢性乙肝患者单核细胞来源的树突状细胞 (DCs)的功能状况及体外对HBV特异性CTL的诱导作用 ,初步探讨诱导特异性抗HBV细胞免疫的途径。方法 :分离慢性乙肝患者外周血单核细胞 ,以GM CSF +IL 4 +TNF α培养诱导DCs,加入HBsAg冲击以诱导HBV特异性DCs。采用FCM测定细胞表面免疫分子CD1a、CD83、CD86、CD80、CD4 0以及HLA DR的表达水平 ,ELISA法检测培养上清中细胞因子IL 6、IL 12的分泌含量 ,MTT法测定DC刺激同种异体淋巴细胞增殖的能力 ,LDH法检测DC诱导的患者外周血T细胞对HepG2 2 2 15 (转染HBVDNA)、HepG2肝癌细胞株及K5 6 2白血病细胞株的细胞毒作用。结果 :HBsAg冲击的DC其表达CD1a、CD83、CD86、CD80、CD4 0、HLA DR表面分子明显高于对照组 (P <0 0 1,P <0 0 5 ) ,分泌IL 12的水平也高于对照组 (P <0 0 1) ,而分泌IL 6的水平则较对照组显著降低(P <0 0 1) ;HBsAg冲击的DC刺激同种异体淋巴细胞增殖的能力明显增强 (P <0 0 5 ) ,并可有效地诱导自体CTL对转HBV基因的HepG2 2 2 15细胞高效特异性杀伤作用 (P <0 0 1)。结论 :慢性乙型肝炎患者单核细胞来源的DCs经HBsAg抗原冲击后 ,生物学活性增强 ,并且能有效地诱导对HBV特异性反应的CTL。     

体外培养系统中各细胞组分在IL-18诱导的肿瘤特异性CTL中的作用

应用rhIL 18在体外培养系统 (coculturesysteminvitro ,CCS )中诱导肿瘤特异性细胞毒性T淋巴细胞 (cytotoxicTlympho cyte ,CTL ) ,探索不同细胞在IL 18起动和促进肿瘤特异性免疫应答方面的作用。采用StemSepTM免疫磁性细胞分离法分离人外周血NK细胞、T细胞及树突细胞 (DC ) ,流式细胞仪分析细胞表型 ,12 5I UdR标记的细胞毒实验检测杀伤活性。结果表明 ,在肿瘤抗原存在的条件下 ,CCS中rhIL 18能够诱导并促进CTL介导的肿瘤特异性杀伤效应 ;并且 ,在rhIL 18诱导肿瘤特异性CTL的过程中 ,rhIL 18、NK细胞、DC及T细胞均起着十分重要的作用 ,缺少任一组份 ,均对诱导肿瘤特异性CTL有明显差异 (P <0 0 1)。提示在CCS中 ,rhIL 18诱导的NK细胞快速杀伤效应及DC的抗原提呈作用 ,在肿瘤特异性CTL产生过程中 ,均起着决定性的作用。     

凋亡肿瘤细胞负载的树突状细胞对抗原特异性CTL的激活

为探讨凋亡Daudi细胞负载的树突状细胞 (DC )激发诱导肿瘤抗原特异性CTL及其生物学特性 ,采用常规方法从人外周血单个核细胞 (PBMC )诱导DC ,激发型CD40mAb联合 50Gyγ射线辐照诱导Daudi凋亡后负载DC ,然后与自体T细胞共育 ,并联合IL 2激发诱导肿瘤特异性CTL ;采用免疫荧光标记和流式细胞仪测定分析膜分子的表达 ;ELISA检测细胞因子的产生 ;Dextran FITC内吞实验分析DC的抗原摄取能力 ;3H掺入试验和51 Cr释放试验分别测定CTL的增殖和细胞毒效应。结果 :(1 )细胞因子序贯体外诱导 7d的DC ,对Dextran吞噬能力最强 ;(2 )CD40mAb诱导联合γ射线辐照 ,能有效介导Daudi细胞的凋亡 ;(3 )抗原负载联合CD40mAb激发可使DC上调表达CD1a、CD80、CD86和HLA DR ,并能促进IL 1 2的分泌 ;(4)凋亡Daudi负载后的DC在激发型CD40mAb作用下 ,能激发和扩增对Daudi细胞具有高效和特异杀伤作用的细胞毒性T细胞。因而认为凋亡肿瘤细胞负载联合CD40mAb刺激的DC可有效激活和扩增肿瘤特异性CTL。     

酶联免疫斑点法检测抗原特异的CTL免疫应答试验条件的优化

目的：探讨酶联免疫斑点（ELISPOT）实验特异性及敏感性的因素，优化酶联免疫斑点法检测抗原特异的CTL免疫应答的实验条件。方法：HLA－A2阳性正常人的外周血单个核细胞在体外经流感病毒抗原肽诱导1周后，观察不同实验条件对酶联免疫斑点法检测抗原特异的CTL免疫应答的影响。结果：CTL诱导时，效应细胞先分离出CD8^＋T细胞组获得的Flu抗原特异的细胞频数要高于CTL诱导后再分离出CD8^＋T细胞组（P＜0．05），自体DC（树状细胞）作APC（抗原提呈细胞）比自体CD8^-PBMC作APC，CTL的诱导效率高且特异（P＜0．05）；使用细胞因子组合（IL－7＋IL－2＋IL－6）优于单纯使用IL－2。CTL行ELISPOT检测时，T2－2细胞较T2－1细胞具有更强抗原提呈功能，增加Flu抗原特异的CD8^＋T细胞频数（P＜0．05）。结论：优化了酶联免疫斑点法检测抗原特异的CTL免疫应答的试验条件，优化的方法在临床肿瘤疫苗的研究中具有应用价值。     

负载人HUVECs抗原的DC疫苗诱导小鼠对宫颈癌U14的特异性免疫反应

目的:探讨负载人脐静脉内皮细胞(HUVEC)抗原的DC疫苗诱导小鼠对宫颈癌U14的特异性免疫反应.方法:原代培养和鉴定人HUVECs,制备抗原,负载树突状细胞(DC),免疫小鼠,免疫结束后1周小鼠皮下注射小鼠宫颈癌U14细胞,观察肿瘤生长大小、检测免疫后小鼠脾细胞体外CTL效应、表面CD3+CD8+百分率和血清抗体滴度,通过细胞免疫组化和Western blot血清特异性反应分析.结果:经免疫组化鉴定成功培养出纯度高的HUVECs,抗原负载DC并注射BALB/c小鼠后,PBS组肿瘤生长最快,DC组和HUVEC-DC组肿瘤也有生长,但生长较慢,在2周后HUVEC-DC组肿瘤消失,3周后DC组肿瘤消失.小鼠脾细胞体外CTL结果显示HUVEC-DC组有明显的特异性杀伤HUVEC的作用.CD3+CD8+百分比提示HUVEC-DC组细胞毒性T细胞比例较其他两组高.小鼠血清抗体滴度示有抗体产生,免疫组化检测示组与HUVEC有特异性抗原抗体反应,Western blot显示在相对分子质量(Mr)130 000和220 000处有特异性条带.结论:负载人HUVECs抗原的DC疫苗和DC疫苗对小鼠宫颈癌U14有抑制作用,HUVEC-DC疫苗诱导了小鼠的细胞和体液免疫,并诱导了针对HUVECs细胞中的某些抗原的应答,这些抗原可能是整合素αν和VEGF-R2.     

Vaccination with dendritic cells pulsed in vitro with tumor antigen conjugated to cholera toxin efficiently induces specific tumoricidal CD8+ cytotoxic lymphocytes dependent on cyclic AMP activation of dendritic cells

We investigated the development of CD8+ tumor-specific cytotoxic lymphocytes (CTL) and protection against tumor growth after vaccination with bone marrow-derived dendritic cells (DC) pulsed with a model protein ovalbumin conjugated to cholera toxin (OVA-CT) in B6 mice using E.G7 tumor cells expressing OVA(257-264) peptide (SIINFEKL) as target cells in vitro and in vivo. Vaccination with OVA-CT-pulsed DC concurrently induced strong CTL in vitro activity and anti-E.G7 tumor protection in vivo in WT, NK-depleted and CD4-deficient mice as well as in IL-12-/- and IFN-gamma-/- mice but not in CD8-deficient mice. Importantly, activation of CTL by OVA-CT-pulsed DC was dependent on CT-induced activation of adenylate cyclase and increased cAMP production by DC associated with increased expression of MHC class I and co-stimulatory molecules (CD80, CD86 and CD40). These results show that vaccination with DC pulsed with antigens (Ag) conjugated to CT induces a strong CTL response and suggest that conjugation of tumor Ag to CT for DC vaccination represents a promising approach for tumor vaccination and immunotherapy.     

BA46基因转染树突状细胞治疗乳腺癌的研究

目的探讨以乳腺癌特异抗原删46基因转导树突状细胞（DC）治疗乳腺癌的可行性。方法取健康人外周血，采用密度梯度离心的方法分离外周血单个核细胞（DC前体细胞），以AIM-V培养基于6孔板培养，贴壁5h，轻轻洗去悬浮细胞（T细胞，冻存备用），取贴壁细胞，将细胞分为基因转染组及对照组，基因转染组感染携带翻46基因的重组腺相关病毒rAAV／BA46/Neo，对照组以293细胞冻融液刺激，两组细胞均采用重组人粒细胞巨噬细胞集落刺激因子（GM—CSF）、白细胞介素4（IL-4）、肿瘤坏死因子-α（TNF-α）诱导DC前体细胞成熟。第7天，收集悬浮细胞（DC），显微镜观察细胞形态，流式细胞仪分析DC的表面标志CD80、CD86、CD40的表达情况；另取该DC与T细胞按1：20比例混合，含5％人血清蛋白的AIM—V为培养基，同时加入IL-2与GM—CSF，共育7d，诱导获得细胞毒性T淋巴细胞（CTL），取删46阳性的乳腺癌细胞株Hs578T为靶细胞，采用^51Cr释放法测量杀伤效率，同时以流式细胞仪检测CTL群体中CD8／CD4和CD8／CD56的比值。结果酗46基因转导的DC表面标志CD80、CD86、CD40的表达均明显高于对照组DC，所激活的T细胞对鲋46阳性的乳腺癌细胞株Hs578T有很好的杀伤效果，此杀伤具有抗原特异性和MHC限制性，且该T细胞中CD8／CIM和CD8／CD56的比值均明显高于对照组（细胞裂解物冲击DC所激活的T细胞）。结论删46基因转染成功制备DC，并诱导特异的CTL，为乳腺癌的DC基因转染疗法打下基础。     

CD154 inhibits tumor-induced apoptosis in dendritic cells and tumor growth.

We have recently demonstrated that murine and human tumors induce apoptosis of dendritic cells (DC). Here, we evaluated the effect of CD40 ligation on the survival of tumor-associated DC and tumor growth. Retroviral transduction of MC38 colon carcinoma cells with the CD154 gene resulted in inhibition of tumor growth. This effect was abrogated in IL-12 knockout mice. Immunohistochemical analysis revealed an increase in CD11c+ (N418) and CD8+ but not NLDC-145+ cells in CD154-transfected tumors in wild-type mice. This increase was less pronounced in IL-12-deficient mice. In vitro, overexpression of CD154 on tumor cells significantly decreased the level of tumor-induced DC apoptosis. Surprisingly, the CD154-induced protection of DC from tumor-induced apoptosis was IL-12 independent in vitro, suggesting an IL-12-dependent and an IL-12-independent mechanism of CD154-induced anti-tumor immunity. Thus, our data suggest a new strategy to improve immunotherapy of cancer by protecting DC from tumor-induced apoptosis.     

负载热休克蛋白60的致耐受性树突状细胞疫苗对小鼠动脉粥样硬化斑块的影响

目的：探讨负载热休克蛋白60（HSP60）的 致耐受性树突状细胞 （DC）接种对ApoE－/－小鼠动脉粥样硬化斑块的影响。 〖HTH 〗方法:制备ApoE－/－小鼠骨髓DC，分别用HSP60或HSP60加雷帕霉素（ra p）处理获得DCHSP60和rap-DCHSP60,体外检测各组DC功能。分别用CFSE 染色 的DCHSP60和rap-DCHSP60及PBS经静脉接种高脂饲养ApoE－/－小鼠3次 ，末次接种后8周观察各组斑块面积，CD4+T细胞和DC在斑块中浸润情况及脾细胞对HSP60 的反应。结果:体外HSP60负载DC CD86表达显著高于未负载DC，而致耐 受DC CD86表达显著低于未负载DC。接种小鼠后，DCHSP60组斑块中炎性细胞浸润明显 多于PBS组，DCHSP60组斑块面积大于PBS组；而rap-DCHSP60组炎性细胞浸润明 显减少，斑块面积显著小于PBS组；HSP60刺激脾细胞后，DCHSP60组IFN-γ分泌增加,而 rap-DCHSP6组IL-10分泌增加，反应呈抗原特异性。结论:负 载HSP60的耐受性DC接种可抑制HSP60特异性免疫反应，抑制动脉粥样斑块中的炎症反应和斑 块的进展。     

MIP-3alpha and MIP-1alpha rapidly mobilize dendritic cell precursors into the peripheral blood

Acquisition of dendritic cells (DCs) or DC precursors in vitro is critical for DC-based immunotherapy. We reported previously that administration of MIP-1alpha mobilized a population of F4/80(-)B220(-)CD11c+ DC precursors into peripheral blood by the expression of CCR1 and CCR5. In this study, we identified a new subset of CCR6+CCR1(-)CCR5(-)B220(-)CD11c(+) cells in MIP-1alpha-administered mice. When cultured with GM-CSF, IL-4, and TNF-alpha, these cells differentiated into mature DCs, possessing the typical morphologic characteristics, phenotypes, and antigen-presenting function (termed CCR6+ DC precursors). Although it did not directly drive the CCR6+ DC precursors, MIP-1alpha could recruit a population of F4/80+CD11c(-) monocyte/macrophage-producing MIP-3alpha in the peripheral blood to mobilize a CCR6+ DC precursor subset of B220(-)CD11c+ DC precursors. Importantly, exogenous administration of MIP-3alpha significantly enhanced MIP-1alpha-induced mobilization of DC precursors. Moreover, these MIP-3alpha- and MIP-1alpha-mobilized DC precursors could be prepared for a DC vaccine capable of eliciting CTL responses to tumor cells, leading to tumor rejection in vitro and in vivo. Taken together, this study further demonstrates the mechanism of DC precursor mobilization induced by MIP-1alpha; that is, besides mobilizing DC precursors with CCR1 and CCR5 expressions, MIP-1alpha recruited F4/80+CD11c(-) monocyte/macrophage-producing MIP-3alpha, which finally mobilized the CCR6+ DC precursor subset to amplify the B220(-)CD11c+ DC precursor population. Furthermore, combined administration of MIP-3alpha and MIP-1alpha may be an efficient strategy for collecting a large number of DCs appropriate for immunotherapy.     

The comparison of cytotoxic T-lymphocyte effects of dendritic cells stimulated by the folate binding protein peptide cultured with IL-15 and IL-2 in solid tumor

The current modalities for treating cancer employ not only single but multiple approaches involving surgery, radiotherapy and chemotherapy. Unfortunately, the survival outcome is not promising even with these approaches. Alternative approaches for cancer therapy are now emerging. Immunotherapy is aiming at both increasing the power, and in redirecting the specificity of the patients' immune system to attack the tumor cells. Recently, many studies using tumor associated lymphocytes (TAL) isolated from malignant ascites cultured in a media containing interleukin-2 exhibit antitumor responses. IL-2 is a lymphokine produced by T-cells. It facilitates activation, sustained growth and rescue from apoptosis. Lately, newly developed IL-15 has also exhibited antitumor activity similar to IL-2. IL-15 is a newly described cytokine produced from monocytes-marcrophages and T-cells. It has a different molecular structure but it functions like IL-2 by binding to the IL-2R beta and gammac chain. These antitumor responses are mediated by the cytotoxic T lymphocytes (CTL) that recognize the antigen in the context of the MHC molecules using the T cell receptors. CD8+-CTL recognize the peptide epitopes that are processed from the cellular proteins in the context of the MHC class I molecules. These peptides have a restricted length of 8-11 amino acids. The folate binding protein (FBP) is overexpressed in over 90% of ovarian and 20-50% in breast cancers. The FBP is the source of the antigenic peptides that are recognized by a number of these CTL-TAL, and is antigenic to both ovarian and breast cancer in vivo. To define the antitumor response of IL-15 and its' FBP immunogenicity, a peptide defining epitope E39 and E75 were presented by the PMBC derived dendritic cells (DC) from healthy donors isolated by the CD14 method to ovarian and breast CTL-TAL. Stimulating both ovarian and breast CTL- TAL by E39 or E75 pulsed DC (DC-E39, DC-E75), in the presence of IL-15 and IL-2 can rapidly enhance or induce the E39 or E75 specific CTL activity. The antitumor activities were measured by a chromium release assay for the tumor specific lysis activity using the ovarian and breast cancer cell lines. The tumor specific lysis activity for the ovarian TALs for IL-15 vs IL-2 were 28.6 +/- 3.9% and 30.3 +/- 3.2%, respectively and in the breast TALs, they were 14.8 +/- 3.1% vs 13.5 +/- 2.9%, respectively. Using autologous tumor cells, a slightly higher tumor specific lysis activity was obtained for the ovarian TALs cultured in IL-15 compared to IL-2 (72.0 +/- 8.2% vs 68.5 +/- 3.6%). However, for the breast TALs, they were 39.5 +/- 4.2% vs 41.5 +/- 3.3%, respectively. IL-15 is a newly developed cytokine that shows promising antitumor activity similar to IL-2. However, it requires lower dosage and is less toxic. Therefore, IL-15 might be a potential anticancer immunotherapeutic agent.     

Interleukin-10-induced T cell unresponsiveness can be reversed by dendritic cell stimulation

The secretion of immunosuppressive factors like interleukin-10 (IL-10), either by tumor cells or by tumor-infiltrating leukocytes, has been recognized as one of the mechanisms involved in tumor immunological escape and a serious obstacle for successful immunotherapy. Therefore, any therapeutic attempts aimed at inducing antitumor immunity in tumor-bearing hosts must overcome this immunosuppressive state. This study aimed to determine whether dendritic cell (DC) immunization, a promising approach to induce antitumor immunity, could break IL-10-induced anergic state in CD4+ T cells, essential cells in generating tumor-specific immunity. We found that the ability of DC to reverse IL-10-induced anergic state in human CD4+ T cells is dependent on the IL-10 concentration that T cells have been exposed to and the degree of DC maturation. The efficacy of mature DC in reversing T cell anergy can be mimicked by higher cell numbers of immature DC. In addition, activated T cells induced by DC stimulation are sensitive to IL-10 treatment. Collectively, our results suggest the use of mature DC and the necessity of antagonizing the action of tumor-derived IL-10 in immunotherapy of cancer with DC immunization.     

In vitro methods for generating CD8+ T-cell clones for immunotherapy from the naïve repertoire

Innovations in gene discovery and the analysis of gene expression are facilitating the identification of a growing number of antigens that could potentially be targeted for immunotherapy of tumors. Methods to reliably generate antigen-specific T-cell responses in vitro would be useful not only to screen candidate antigens for immunogenicity prior to embarking on in vivo vaccination trials, but also to generate T-cell lines or clones that could be used directly for adoptive immunotherapy approaches. Although many techniques have proven successful for expanding ex vivo effector cells from antigen-specific memory CD8⁺ cells that have been primed in vivo, methods to reliably generate high-avidity CTL clones from the naïve repertoire have not been well described. Various methods for the induction and expansion of antigen-specific CD8⁺ CTL clones from healthy A2⁺ donors were compared, using WT1 as a model tumor-associated antigen for which there is a low frequency of precursor T cells in naïve individuals. In contrast to the well-studied Melan-A/MART-1 (Melan-A) A2-restricted response, for which the CD8⁺ T-cell precursor frequency in the naïve repertoire is unusually high, successful expansion of WT1-specific CD8⁺ T cells appeared to be more dependent upon cell culture conditions. In particular, primary stimulation with autologous peptide-loaded monocyte-derived DC generated in 48 h (DC2d) was more effective in expanding WT1-reactive populations of CTL than stimulation with DC generated using the more standard week-long protocol (DC7d). Adding supplemental IL-7 2 to 3 days after initiation of a stimulation cycle expanded antigen-specific cells within CTL lines more efficiently than including the cytokine from the beginning of the cycle. Following primary stimulation with peptide-loaded mature DC, subsequent restimulation with peptide-loaded PBMC as the stimulators was more effective at expanding antigen-specific cells than repeated stimulation with mature DC. Using these techniques, high-avidity CTL clones specific for an A0201-restricted epitope of WT1 have been generated from nearly all normal A2⁺ donors tested. Such clones have been demonstrated to be capable of recognizing and lysing leukemic cells, and will soon be tested for therapeutic activity in clinical trials of adoptive immunotherapy in patients with relapsed leukemia after transplantation.