人AFP腺病毒载体感染的树突状细胞诱导小鼠抗肝癌免疫

目的探讨复制缺损型腺病毒载体(Ad)介导异种AFP修饰的树突状细胞(DCs)诱发抗肝癌免疫、打破肿瘤免疫耐受的效果。方法从HepG2和Hepa16细胞中克隆人和小鼠AFP,插入Ad中构建AdhAFP和AdmAFP。用AdhAFP或AdmAFP感染小鼠骨髓来源的DC后,在无或有删除CD4或CD8情况下免疫C57BL/6小鼠,7d后取脾细胞行51Cr释放实验,检测特异性CTL杀伤活性;或给免疫小鼠接种Hepa16肝癌细胞,观察荷瘤小鼠成活情况。结果AdhAFP/DCs免疫小鼠1周后其细胞毒性T淋巴细胞杀伤活性明显强于AdmAFP/DCs。AdhAFP/DCs免疫小鼠后1周接种5×106Hepa16肝瘤细胞,2个月后仍然有80%的小鼠无瘤生长;而接种1×106Hepa16细胞至AdmAFP/DCs免疫小鼠,2个月后小鼠成活率为20%。删除小鼠CD4或CD8T细胞均使AdhAFP/DCs诱发的抗肿瘤免疫反应消失。结论Ad介导异种AFP修饰的DCs能有效地打破肿瘤的免疫耐受,诱发强烈的抗原特异性细胞免疫反应,这种特异性细胞免疫反应是CD4和CD8依赖性的。     

腺病毒载体介导人KDR胞外段诱导抗小鼠肝癌的免疫效应

目的：探讨复制缺陷型腺病毒载体（Ad）介导人血管内皮细胞生长因子受体-2（hVEGFR-2或hKDR）胞外段诱导抗小鼠肝癌血管免疫及打破免疫耐受的效果。方法：构建Ad hKDRE,用Ad hKDRE皮内免疫C57BL/6小鼠,7d后取脾细胞作为效应细胞（E）,Hepa1-6/mKDR作为靶细胞（T）,行乳酸脱氢酶（LDH）释放实验检测特异性CTL杀伤活性;给免疫小鼠接种肝癌细胞Hepa1-6,观察荷瘤小鼠成活情况。结果：Ad hKDRE免疫小鼠1周后,在E∶T为100∶1、50∶1和25∶1时,Ad hKDRE诱导的6hCTL杀伤率分别为（81.5±5.6）%、（68.4±5.5）%和（39.6±3.9）%。Ad hKDRE免疫小鼠1周后接种2×10^6 Hepa1-6肝癌细胞,观察2个月无小鼠成瘤;接种5×106 Hepa1-6细胞,小鼠无瘤成活率为60%。上述CTL效应和抗成瘤作用在清除CD8＋和CD4＋ T淋巴细胞后消失。结论：Ad介导异种（人）KDR胞外段能有效地打破小鼠肝癌的免疫耐受,诱发强烈的抗原特异性细胞免疫反应,这种特异性细胞免疫反应是CD4^＋和CD8^＋ T细胞依赖性的。     

自体肿瘤瘤苗对荷瘤鼠Th1、Th2型细胞因子及细胞毒作用的影响

目的研究经处理的H22肝癌细胞肿瘤瘤苗作为全细胞瘤苗对H22荷瘤小鼠体内Th1/Th2细胞比例和细胞因子的影响以及CTL的杀伤活性.方法用加重组白细胞介素2、重组粒细胞单核细胞集落刺激因子及福氏不完全佐剂制成疫苗,建立荷瘤小鼠模型,用51Cr释放法测定瘤苗免疫组、荷瘤组、正常组小鼠脾细胞对亲本H22肝癌细胞的杀伤活性;流式细胞仪检测单个核细胞中的Th1和Th2细胞,并取血检测血清中IL-10、IFN-γ水平.结果效靶比为200:1时,免疫小鼠脾细胞体外杀伤亲本H22肝癌细胞的杀伤率为38.3%,显著高于荷瘤组的13.6%,正常组的7.5%,以及对S180细胞的9.1%(P均＜0.05).瘤苗免疫组Th1细胞及Th1/Th2细胞的比值显著升高(P＜0.01),血清IFN-γ较对照组明显升高(P＜0.01);血清IL-10较对照组明显降低(P＜0.01).结论肿瘤细胞加小剂量IL-2和GM-CSF及佐剂组成的肿瘤细胞瘤苗可激发特异性细胞介导的免疫反应,改善抗肿瘤免疫反应.     

人工抗原提呈细胞体外激活肝癌CD8+T细胞

目的:探讨人工抗原提呈细胞(artificial antigen presenting cell,aAPC)K32/4-IBBL/CD86对肝癌CD8+T细胞的活化作用。方法:磁珠法分选HLA-A 2阳性肝癌患者外周血CD8+T细胞,aAPC与CD8+T细胞按不同比例(1∶1、1∶2、1∶3)混合培养,诱导CTL。锥虫蓝拒染法测定CTL的生长曲线,MTS/PMS法检测CTL的增殖,流式细胞术检测CTL分泌IFN-γ的能力,MTT法检测CTL对人肝癌细胞株BEL7402和自体肝癌细胞的杀伤作用。结果:肝癌患者外周血CD8+T细胞经aAPC作用后,增殖能力明显增强,按1∶1、1∶2、1∶3比例混合培养后第8天分别为(21.2±2.5)×105、(17.6±3.2)×105、(15.3±2.8)×105,明显高于对照组的(8.5±0.15)×105(P<0.01),混合培养后分泌IFN-γ的CTL比例分别为(26.2±1.91)%、(21.3±1.38)%、(18.6±1.20)%,明显高于对照组的(0.1±0.02)%(P<0.01)。aAPC活化的CTL对BEL7402细胞和自体肝癌细胞的杀伤率较对照组显著增强,按1∶3混合培养后得到的CTL对BEL7402细胞和自体肝癌细胞的杀伤率分别为(21.8±4.3)%和(25.6±3.6)%,明显高于对照组的(3.8±1.8)%和(3.8±2.0)%(P<0.01);效靶比为50∶1时,1∶1混合培养组CTL对BEL7402细胞的杀伤率(56.8±3.0)%和对自体肝癌细胞的杀伤率(64.8±4.2)%明显高于1∶2混合培养组的(44.3±2.6)%、(56.1±3.4)%和1∶3混合培养组的(38.9±4.7)%、(46.2±4.7)%(P<0.05)。结论:aAPC在体外可高效活化肝癌患者CD8+T细胞,诱导CTL分泌IFN-γ,且CTL对人肝癌细胞株BEL7402和自体肝癌细胞具有明显的杀伤作用。     

负载人AFP肽段的树突细胞在体内外对小鼠肝癌的抑制作用

背景与目的:甲胎蛋白(alpha-fetoprotein,AFP)是原发性肝细胞癌(hepatocellular carcinoma,HCC)免疫治疗的一个良好的靶分子,如何克服对自身抗原的免疫耐受状态是诱导有效抗肿瘤免疫反应的关键.本研究探讨异种同源蛋白疫苗负载人AFP肽段的树突细胞(human AFP-derived peptide-pulsed dendritic cells,hAFP-DCs)对小鼠肝癌的体外杀伤作用和体内抑瘤效应.方法:传统方法制备骨髓来源的DCs.MTT法检测hAFP-DCs诱导的CTL对小鼠肝癌细胞Hepal-6的体外杀伤活性.建立Hepal-6细胞C57BL/6小鼠移植瘤模型,分别瘤内注射hAFP-DCs、DCs和PBS(每周两次),观察小鼠肿瘤体积和荷瘤存活时间.结果:成功制备小鼠骨髓来源的DCs.体外杀伤实验显示,hAFP-DCs刺激组和单纯DCs刺激组CTL对Hepal-6细胞的杀伤作用强于PBS组,但组间差异无统计学意义(P>0.05).体内实验表明.每个C57BL/6小鼠接种7×106个Hepal-6细胞31 d后,hAFP-DCs、DCs和PBS组小鼠平均移植瘤体积分别为(195.04±155.22)mm3、(360.65±209.02)mm3和(756.19±503.24)mm3,组间比较差异有显著性(P<0.001).在40 d的观察期内,小鼠的累积存活率分别为100%、90%和50%(P=0.008).结论:负载人AFP抗原肽的DEs疫苗在体外和体内均能有效抑制小鼠肝癌的生长.     

负载小鼠端粒酶逆转录酶基因的树突状细胞体内诱导抗肝癌免疫应答

目的 探讨小鼠端粒酶逆转录酶(mTERT)基因修饰的树突状细胞(Ad-mTERT-DC)在体内诱导抗肝癌活性的情况.方法 选用Bal B/c小鼠肝癌种植模型,用携带mTERT基因的重组腺病毒载体(Ad-mTERT)转染小鼠体外培养的DC,对同系小鼠进行免疫.采用酶联免疫吸附法(ELISA)检测脾细胞体外抗原再刺激后白介素2(IL-2)和γ干扰素(IFN-γ)水平,酶联免疫斑点法(ELISPOT)检测分泌IFN-γ细胞的数量,51Cr释放法检测细胞毒T淋巴细胞杀伤活性.接种H22细胞后,观察肿瘤大小及荷瘤小鼠存活情况.并进一步观察,在H22移植瘤存在的情况下,Ad-mTERT-DC是否能够有效抑制肿瘤生长.结果 小鼠脾细胞体外接受抗原再刺激后,Ad-mTERT组IL-2和IFN-γ水平以及IFN-γ分泌细胞的数量分别为871.25 pg/ml、169.15 ng/ml和378/106个脾细胞,显著高于Ad-GFP组(131.6 pg/ml、15.4 ng/ml和36/106个脾细胞,均P<0.05)、DC组(71.3 pg/ml、10.5ng/ml和21/106个脾细胞)和PBS组(65.8 pg/ml、7.4 ng/ml和18/106个脾细胞,均P<0.05).Ad-mTERT-DC能诱导特异性CTL的产生,在效靶比为90:1时,Ad-mTERT组的特异性杀伤率为58.7%,明显高于Ad-GFP组(10.3%)、DC组(2.9%)和PBS组(1.7%).接种后第27天,Ad-mTERT组中成瘤小鼠的肿瘤平均直径明显低于各对照组(P<0.05),小鼠存活时间明显延长(P<0.05).Ad-mTERT组抑瘤率为43.6%,明显高于PBS组、DC组和Ad-GFP组(均P<0.01).结论 Ad-mTERT-DC在小鼠体内可诱导出mTERT抗原特异性的抗肿瘤活性,对肝癌有预防和治疗作用.     

热休克蛋白72-甲胎蛋白抗原表位肽复合物抗小鼠肝癌Hepal-6细胞免疫的实验研究

目的:以热休克蛋白72(HSP72)-甲胎蛋白(AFP)抗原表位肽复合物免疫小鼠,研究该复合物针对AFP肿瘤是否具有特异性抗肿瘤免疫.方法:以HSP72-AFP多肽复合物皮下注射免疫昆明小鼠,并分别以AFP多肽和HSP72单独免疫小鼠为对照组.ELISA法检测免疫后小鼠血清IFN-γ水平、MTT法检测各免疫组小鼠淋巴细胞对肝癌Hepal-6细胞的杀伤作用、以小鼠体内瘤负荷实验评价蛋白复合物的免疫效应.结果:HSP72-AFP多肽复合物组小鼠血清IFN-γ水平、淋巴细胞对Hepal-6细胞的杀伤作用均显著高于AFP多肽和HSP72组(P＜0.01).HSP72-AFP多肽复合物组瘤体积也明显小于AFP多肽和HSP72免疫组(P＜0.01).结论:HSP72-AFP多肽复合物疫苗可诱导荷瘤小鼠产生针对AFP肿瘤的特异性细胞免疫,其对瘤细胞的杀伤效应明显优于两者单一的多肽纯化疫苗.表明HSP72-AFP多肽复合物可诱导小鼠产生有效的抗肿瘤免疫.     

AFP基因转染的树突状细胞的生物学特性及靶向性CTL细胞毒作用

目的:观察基因转染的树突状细胞生物学特性及靶向性CTL对肿瘤细胞的杀伤作用。方法:用重组IL-4和GM-CSF诱导扩增小鼠骨髓来源的单个核细胞,将表达AFP基因的重组腺病毒转染DC(dendriticcells,DC),构建基因转染的DC瘤苗,并免疫C57BL/6小鼠。用流式细胞术(FCS)检测转染前后DC细胞表面分子MHCI、MHCII、LFA、ICAM、B7.1、和B7.2等的变化。取免疫小鼠脾细胞诱导细胞毒性CTL,LDH非放射性细胞毒性试验检测其对不同肿瘤细胞的杀伤作用。用ELISA法检测CTL诱导过程中TNF-α和IFN-γ分泌变化规律。结果:AFP基因转染后的DC分子表面高表达MHCI、MHCII、LFA、ICAM、B7.1、和B7.2等分子,尤其是MHCII、ICAM和LFA分子,与转染前比较具有显著性差异(P<0.05)。与对照组比较,AFP抗原诱导的靶向性CTL对AFP分泌性肿瘤细胞具有更强的杀瘤活性,且在CTL诱导过程中TNF-α和IFN-γ分泌水平较对照组也有显著性差异。结论:AFP基因重组腺病毒修饰的DC能表达高水平的MHCI、MHCII、LFA、ICAM、B7.1、和B7.2等分子,为CTL进一步活化提供了共刺激信号;用该瘤苗免疫C57BL/6J小鼠,能诱导出针对AFP抗原的靶向性CTL,从而实现对AFP分泌性肿瘤细胞的特异性杀伤作用。     

融合基因mGM-CSF/hIL-2在肝癌细胞瘤苗特异性免疫治疗中的作用

背景与目的:手术切除是治疗肝癌的主要方法,但对其术后的复发转移却无更好的办法。近年来,免疫学的发展使肝癌的治疗有了更好的治疗方法。本研究旨在通过制备人白细胞介素2(hIL-2)与鼠粒-单核细胞集落刺激因子(mGM-CSF)融合基因修饰的H22肝癌瘤苗,观察其特异性抗肿瘤免疫作用。方法:用含hIL-2与mGM-CSF融合基因的真核表达载体,在体外转染H22细胞,制成疫苗,皮下接种小鼠,同时建立荷瘤小鼠模型。用51Cr释放法测定瘤苗免疫组、空载组、未转染组小鼠脾细胞对亲本H22细胞的杀伤活性。取血检测血清中IL-10、IFN-γ水平,观察小鼠存活期。结果:成功制备了含有hIL-2与mGM-CSF融合基因的H22肝癌瘤苗。免疫小鼠脾细胞体外对H22细胞的杀伤率为38.3%,显著高于对S180细胞的9.1%,以及空载组和未转染组的13.6%和7.5%(P<0.05)。转基因瘤苗免疫组血清IFN-γ为(12.83±0.75)pg/mL,较空载瘤苗组的(7.83±0.65)pg/mL明显升高(P<0.01),血清IL-10[(4.58±0.34)pg/mL]较空载瘤苗组的(8.15±0.28)pg/mL明显降低(P<0.01)。同时,转基因瘤苗免疫组小鼠存活期为(40±6)d,较对照组[空载瘤苗组(30±3)d,未转染组(19±4)d]明显延长。结论:转染hIL-2与mGM-CSF融合基因的同系肿瘤细胞瘤苗可激发特异性细胞介导的免疫反应,改善抗肿瘤免疫反应,延长荷瘤小鼠存活期。     

腺病毒介导的AFP基因修饰树突状细胞的体外生物学特性

目的: 探讨腺病毒介导AFP基因修饰树突状细胞瘤苗体外生物学活性。方法:将携带小鼠AFP全长cDNA的重组腺病毒表达载体AdAFP转染BMDC，构建AFPDC肝癌瘤苗，采用电化学发光免疫测定法确证AFPDC转染的有效性，FACS检测表面分子和内吞功能，3HTdR掺入法检测T细胞增殖反应的能力，51Cr 释放法检测CTL活性。结果: AFP基因转染12 h后DC及其培养上清中可检到AFP的表达，表明腺病毒介导的AFP基因转染的有效性。AFPDC与BMDC比较B7分子明显上调，MHC分子也有轻度升高，内吞功能降低(P<0.05)。AFPDC激发同基因型小鼠T细胞增殖功能均明显高于DC对照组和LacZDC组(P<0.05)。AFPDC体外诱导CTL对Hepa16肿瘤细胞的杀伤作用具有特异性。结论: 肝癌相关基因AFP可作为抗肝癌基因治疗的切入点，该研究为肝癌树突状细胞体内免疫治疗提供了实验依据。     

Identification of alpha-fetoprotein-derived peptides recognized by cytotoxic T lymphocytes in HLA-A24+ patients with hepatocellular carcinoma

Alpha-fetoprotein (AFP) has been proposed as a potential target forT-cell-based immunotherapy for hepatocellular carcinoma (HCC), but the number of its epitopes that have been identified is limited and the status of AFP-specific immunological responses in HCC patients has not been well-characterized. To address the issue, we examined the possibility of inducing AFP-specific cytotoxic T cells (CTLs) using novel HLA-A*2402-restricted T-cell epitopes (HLA, human leukocyte antigen) derived from AFP and then analyzed the relationship between its frequency of occurrence and clinical features associated with patients having HCC. Five AFP-derived peptides containing HLA-A*2402 binding motifs and showing high binding affinity to HLA-A*2402 induced CTLs to produce IFN-gamma and kill an AFP-producing hepatoma cell line. The frequency of AFP-specific CTLs was 30-190 per 1 x 10(6) peripheral blood mononuclear cells, which was the same as that of other immunogenic cancer associated antigen-derived epitopes. Analyses of the relationships between AFP-specific CTL responses and clinical features of patients with HCC revealed that AFP epitopes were more frequently recognized by CTLs in patients with advanced HCC correlating to tumor factors or the stage of TNM classification. The analyses of CTL responses before and after HCC treatments showed that the treatments changed the frequency of AFP-specific CTLs. In conclusion, we identified five HLA-A*2402-restricted T-cell epitopes derived from AFP. The newly identified AFP epitopes could be a valuable component of HCC immunotherapy and for analyzing host immune responses to HCC.     

应用细胞因子缓释微球的肿瘤疫苗治疗肝癌的研究

目的 探讨采用细胞因子缓释微球的肿瘤疫苗预防和治疗肝癌的疗效及抗癌机制。方法 我们研制开发了一种肿瘤疫苗,其组成是固定的肿瘤细胞或组织碎片、细胞因子缓释微球和免疫辅助药。采用多聚甲醛固定的小鼠Hepal-6细胞或肿瘤碎片、微球包装的GM—CSF和／IL—2和合成TiterMax Gold等不同成份的瘤苗皮内接种C57BL／6J小鼠,随后肝内接种活体Hepal-6细胞。结果 对照组15只小鼠全部发展成肝肿瘤;含有固定Hepal-6细胞和IL-2及GM—CSF微球的肿瘤疫苗,80％小鼠获得保护。再加入免疫辅助剂TiterMax Gold的肿瘤疫苗,则87％小鼠获得保护。将Hepal-6细胞接种于左躯干皮下。肿瘤长至直径5mm时,皮内接种肿瘤疫苗2次。结果显示,对照组肿瘤继续生长。疫苗组在第2次接种后7—10天,10只小鼠中9只肿瘤生长受到抑制,随后明显缩小。60％小鼠的肿瘤完全消散。细胞毒性实验结果显示,未接种疫苗的小鼠脾细胞不能杀灭Hepal-6细胞和其他肿瘤细胞;而接种疫苗的小鼠脾细胞对Hepal-6细胞杀瘤活性达41％,但对B16—Fl,Lewis肺癌细胞(LLC),肾癌细胞(Renca),膀胱癌细胞(MBT-2)则无效。疫苗的Ⅰ期临床实验结果显示肝癌疫苗能有效地预防肝癌术后复发,诱导DTH反应。结论 肝癌疫苗能有效预防和治疗原发性肝癌,其抗瘤机制是诱导内源性抗原特异性CTL反应,其杀瘤特性是由典型的：MHC—Ⅰ限制的CD8^ T细胞所介导的。     

Combinations of tumor-specific CD8+ CTLs and anti-CD25 mAb provide improved immunotherapy

One new approach to cancer therapy is based on the adoptive transfer of tumor-specific cytotoxic T cells and anti-CD25 antibodies. In the present study, CD8+ and IFN-gamma secreting T lymphocytes (CTLs) were enriched as tumor-specific cytotoxic T cells from spleen lymphocytes of mice bearing the Renca tumor (a murine renal carcinoma line originating from a BALB/c mouse) after stimulation with tumor cells. An anti-CD25 IL-2Ralpha(anti-CD25) mAb from hybridoma PC61 was used for depletion for CD4(+)CD25(+) regulatory T (Treg) cells. Treatment-efficacy for tumor-bearing mice was compared using 4 systems: 1, whole spleen lymphocytes stimulated with tumor cells in vitro from tumor-bearing mice; 2, CTLs; 3, anti-CD25 mAbs; 4, CTLs and anti-CD25 mAbs. At the 50th day after tumor inoculation, in the group which received anti-CD25 mAb for depletion of T cells and inoculation of CTLs, tumors had disappeared and no re-growth was observed. In contrast, all mice of the non-treated and other three groups, treated with whole spleen cells alone, CTLs alone and anti-CD25 mAb alone, had died. These results showed that a combination of Treg cell-depletion using anti-CD25 mAbs and CTL administration is a feasible approach for treatment of cancers which warrants further exploration in the clinical setting.     

小鼠AFPcDNA真核表达载体的构建、表达及体外抗肝癌免疫活性的检测

背景与目的:探索肝癌细胞的突变基因产物——具有潜在抗原性的异常蛋白质而无法形成有效免疫原的机理,寻找肝癌的特异性抗原,并在此基础上研制出治疗肝癌的DNA疫苗将对肝癌的免疫学治疗产生积极的影响。本实验构建BALB/c小鼠具有分泌性信号肽的AFP1cDNA和去掉信号肽的AFP2cDNA真核表达载体,分别在小鼠树突细胞(dendriticcells,DCs)中表达,并观察其在体外抗肝癌免疫中的作用。方法:采用RT-PCR方法自小鼠肝癌细胞株H22中扩增出具有分泌性信号肽的AFP1cDNA和去掉分泌性信号肽的AFP2cDNA,将该基因定向插入真核表达载体PEGF-N3中;同时培养经rmGM-CSF、rmIL-4诱导的小鼠骨髓细胞,体外获取大量DCs,脂质体转染PEGF-N3/AFP1、PEGF-N3/AFP2至DCs进行表达、鉴定。将DCs疫苗与同源小鼠脾淋巴细胞混合培养,ELISA方法测定脾细胞γ-干扰素(IFN-γ)分泌活性,51Cr释放法测定脾淋巴细胞的特异性杀伤活性。结果:从H22中克隆到AFP1cDNA和AFP2cDNA,经测序完全正确,所构建的真核表达质粒PEGF-N3/AFP1和PEGF-N3/AFP2在小鼠DCs中获得稳定高效表达,其中PEGF-N3/AFP2明显刺激T细胞增殖,刺激指数(SI)为5.12±1.46,明显高于空质粒组(1.42±0.73)。AFP2/DC疫苗对H22细胞的特异性杀伤活性[(88.15±16.47)%]明显高于空质粒组[(12.72±5.45)%]。结论:成功地构建了真核表达载体PEGF-N3/AFP1和PEGF-N3/AFP2,编码去掉分泌性信号肽的PEGF-N3/AFP2转染的DC,能够诱导较强的特异性抗肝癌免疫效应。其机制可能为诱导肝癌细胞凋亡。     

An attenuated Salmonella oral DNA vaccine prevents the growth of hepatocellular carcinoma and colon cancer that express alpha-fetoprotein

Antitumor vaccination therapies using attenuated Salmonella typhimurium carrying plasmid DNA encoding tumor-associated antigens are currently under preclinical development. In the present study, we first established a useful method to facilitate in vivo monitoring of attenuated S. typhimurium uptake using a bioluminescent lux gene operon plasmid. Following transformation with the lux gene operon construct, mice were fed with various amounts of attenuated S. typhimurium-lux to monitor in vivo clearance over a period of 24 h. We found that the ingested attenuated S. typhimurium-lux cells were almost cleared out 9 h postfeeding, as judged by a significant decrease in bioluminescence. We further examined the therapeutic efficacy of vaccination using attenuated S. typhimurium carrying the mouse alpha-fetoprotein (AFP) gene against a cancer line CT26-murine alpha-feto protein (mAFP) that stably expresses AFP and mouse hepatocellular carcinoma (HCC) Hepa1-6. Attenuated S. typhimurium oral DNA vaccine was found to promote protective immunity against both CT26-mAFP and Hepa1-6 tumor cells growth. The oral DNA vaccine significantly increased the life span of tumor-challenged mice in both tumor models. Together, these results suggest that vaccination with the attenuated S. typhimurium oral DNA vaccine that carries the AFP gene could be a promising strategy to prevent HCC development.     

Alpha-fetoprotein synthesis in human hepatocellular carcinoma: correlation with hepatitis B surface antigen expression.

We analyzed the pattern of alpha-fetoprotein (AFP) synthesis in 40 consecutive human hepatocarcinomas (HCC) in relation to hepatitis B viral (HBV) infection. In addition, histopathological characteristics of liver parenchyma and the tumor itself were examined. Elevated AFP (> 20 ng/ml) were found in 90% of HCC patients and in none of the controls. In 35% of HCC cases, serum AFP was above 100,000 ng/ml. AFP levels were significantly higher in patients seropositive for hepatitis B surface antigen (HBsAg) compared with their negative counterparts (mean log[AFP]: 4.28 +/- 1.67 vs. 3.28 +/- 1.96, respectively; geometric mean (GM): 19,322.6 ng/ml and 1939.5 ng/ml, respectively; p < 0.05). Furthermore, serum AFP levels were higher in HCC patients with liver cirrhosis than in those without (log[AFP]: 4.43 +/- 1.58 vs. 3.23 +/- 1.98, respectively; p < 0.05). However, the relationship of cirrhosis with AFP was confounded by the high prevalence of HBsAg in cirrhotic HCC patients. There was no correlation of AFP with either liver necrosis (abnormal AFP in 45% of cases; mean log[AFP]: 3.99 +/- 1.91 vs. 3.75 +/- 1.85 for HCC with and without necrosis, respectively; 0.05 < p < 0.68, not significant (NS)), or inflammation (abnormal AFP in 25%; mean log[AFP]: 4.33 +/- 1.62 vs. 3.70 +/- 1.93 for HCC with and without inflammation, respectively; 0.05 < p < 0.39, NS). A vast majority of HCC (75%) were moderately (grade 2-3) or poorly differentiated tumors (grade 3, grade 4, or combined grade 3-4). Serum AFP did not correlate with tumor grade. Immunohistochemical analysis of HBsAg and AFP confirmed the serological findings, and confirmed earlier observations of elevated AFP in HBsAg-positive patients. These results may reflect pathogenic and biological differences between HBsAG-secreting and nonsecreting HCC.     

Identification of HLA-A2- or HLA-A24-restricted CTL epitopes possibly useful for glypican-3-specific immunotherapy of hepatocellular carcinoma.

PURPOSE AND EXPERIMENTAL DESIGN: We previously reported that glypican-3 (GPC3) was overexpressed, specifically in hepatocellular carcinoma (HCC) and melanoma in humans, and it was useful as a novel tumor marker. We also reported that the preimmunization of BALB/c mice with dendritic cells pulsed with the H-2K(d)-restricted mouse GPC3(298-306) (EYILSLEEL) peptide prevented the growth of tumor-expressing mouse GPC3. Because of similarities in the peptide binding motifs between H-2K(d) and HLA-A24 (A*2402), the GPC3(298-306) peptide therefore seemed to be useful for the immunotherapy of HLA-A24+ patients with HCC and melanoma. In this report, we investigated whether the GPC3(298-306) peptide could induce GPC3-reactive CTLs from the peripheral blood mononuclear cells (PBMC) of HLA-A24 (A*2402)+ HCC patients. In addition, we used HLA-A2.1 (HHD) transgenic mice to identify the HLA-A2 (A*0201)-restricted GPC3 epitopes to expand the applications of GPC3-based immunotherapy to the HLA-A2+ HCC patients. RESULTS: We found that the GPC3(144-152) (FVGEFFTDV) peptide could induce peptide-reactive CTLs in HLA-A2.1 (HHD) transgenic mice without inducing autoimmunity. In five out of eight HLA-A2+ GPC3+ HCC patients, the GPC3(144-152) peptide-reactive CTLs were generated from PBMCs by in vitro stimulation with the peptide and the GPC3(298-306) peptide-reactive CTLs were also generated from PBMCs in four of six HLA-A24+ GPC3+ HCC patients. The inoculation of these CTLs reduced the human HCC tumor mass implanted into nonobese diabetic/severe combined immunodeficiency mice. CONCLUSION: Our study raises the possibility that these GPC3 peptides may therefore be applicable to cancer immunotherapy for a large number of HCC patients.     

Growth suppression of the hepatocellular carcinoma cell line Hepa1-6 by an activatable interferon regulatory factor-1 in mice

Hepatocellular carcinoma (HCC) is a highly malignant tumor with a poor prognosis and few therapeutic options. The aim of the study was to evaluate the potential of IFN regulatory factor-1 (IRF-1) for cytokine gene therapy of HCC using an IRF-1/human estrogen receptor fusion protein (IRF-1hER), which is reversibly activatable by beta-estradiol (E2). IRF-1hER stably expressing murine Hepa1-6 HCC cells (HepaIRF-1hER) were characterized by lowMHC 1, highCD54, and lack of MHC II, CD80, and CD86 expression. Activation of HepaIRF-1hER cells induced a highMHC I, lowMHC II, and highCD54 phenotype. Furthermore, they were characterized by IFN-beta secretion, decreased anchorage-independent growth in a soft agar assay, and diminished cell growth. Tumor growth in E2-treated syngeneic C57L/J mice, but not in E2-untreated mice, was suppressed. These E2-treated mice were protected against rechallenge with HepaIRF-1hER and wild-type Hepa1-6 tumors even in the absence of E2, suggesting induction of tumor specific immunity. In fact, significant CTL activity against Hepa1-6 tumors and the endogenously expressed HCC-specific self antigen alpha-fetoprotein was observed. Antitumoral effects, however, were only partially dependent on both CD4+ and CD8+ T cells. IRF-1 treatment of mice bearing HepaIRF-1hER tumors resulted in growth arrest of tumors, and a significant survival benefit was observed in comparison to E2-untreated mice. In conclusion, our data demonstrate that IRF-1 suppresses HCC growth through both a direct antitumor growth effect and enhanced immune cell recognition of the tumor and is a promising candidate for gene therapy of HCC.     

Tumor irradiation followed by intratumoral cytokine gene therapy for murine renal adenocarcinoma

To circumvent the toxicity caused by systemic injection of cytokines, cytokine cDNA genes encoding the human interleukin IL-2 cDNA (Ad-IL-2) and murine interferon IFN-gamma gene (Ad- IFN-gamma) were inserted into adenoviral vectors. These constructs were used for intratumoral gene therapy of murine renal adenocarcinoma Renca tumors. Treatment with three doses of Ad-IL-2 or Ad- IFN-gamma, given a day apart, was more effective than single-dose gene therapy. We found that tumor irradiation enhanced the therapeutic efficacy of Ad-IL-2 and Ad-IFN-gamma intratumoral gene therapy. Tumor irradiation, administered 1 day prior to three doses of Ad-IL-2 treatment, was more effective than radiation or Ad-IL-2 alone, resulting in tumor growth arrest in all mice, increased survival and a consistent increase in complete tumor regression response rate. Complete responders rejected Renca tumor challenge and demonstrated specific cytotoxic T-cell activity, indicative of specific tumor immunity. The effect of radiation combined with three doses of Ad-IFN-gamma was less pronounced and did not lead to tumor immunity. Histological observations showed that irradiation of the tumor prior to gene therapy increased tumor destruction and inflammatory infiltrates in the tumor nodules. These findings demonstrate that tumor irradiation improves the efficacy of Ad-IL-2 gene therapy for induction of antitumor immune response.