自体肿瘤免疫激活剂诱导抗肝癌免疫的研究

目的 采用含有固定的肝细胞癌(HCC)细胞或组织碎片、粒细胞-巨噬细胞集落刺激因子(GM-CSF)和白介素-2(IL-2)的生物可降解缓释微球和结核菌素的肿瘤免疫激活剂进行皮内接种,观察对小鼠肝肿瘤的预防免疫作用和预防人HCC切除术后复发的效果.方法 动物实验:C57BL/6J小鼠尾部皮内注射Hepa 1-6肿瘤免疫激活剂两次,第2次免疫注射后7 d,左后肢皮下注射1×107活Hepa 1-6细胞,观察肿瘤的生长情况.临床研究:50例肝癌根治切除术后患者采用随机、对照的方法分为免疫激活剂接种组和对照组.结果 Hepa 1-6细胞注射同源性小鼠后,对照组(A组)18只小鼠全部发展成肝肿瘤;而接种含有固定Hepa 1-6细胞的免疫激活剂(B组)的18只小鼠中有4只无肿瘤生长;接种含有IL-2/GM-CSF微球和结核菌素(C组)的18只小鼠中有3只无肿瘤生长:而接种含有固定Hepal-6细胞和IL-2/GM-CSF微球和结核菌素(Tuberculin)的肿瘤免疫激活剂(D组)的18只小鼠中12只无肿瘤的生长,67%的小鼠获得保护.在HCC肿瘤免疫激活剂的临床试验中未见副作用.24例患者中17例出现了抗HCC迟发型超敏反应.剂量-1、-2免疫激活剂组术后1、2、3年复发率分别为25%(25%)、37.5%(37.5%)和50%(37.5%);剂量-4免疫激活剂组术后1、2年复发率分别为O%、12.5%.而对照组HCC切除术后1、2、3年复发率分别为30.8%、53.8%和61.5%.接种剂量-2、-4 HCC免疫激活剂患者的术后复发率明显低于对照组(P<0.05).结论 这种细胞因子缓释微球的肝癌免疫激活剂具有较强的抗小鼠肝肿瘤的效果;可预防肝癌切除术后复发.     

紫杉醇与肿瘤疫苗联合应用对小鼠Lewis肺癌皮下移植瘤的治疗效果

目的： 〖HT5"SS〗评价化疗药物紫杉醇联合应用肿瘤疫苗对小鼠Lewis肺癌皮下移植瘤的治疗效果。〖HT5W〗方法： 〖HT5"SS〗以编码有GMCSF的腺病毒感染Lewis肺癌细胞3LL,制备肿瘤疫苗3LL/GMCSF。以2×104个3LL瘤细胞皮下注射C57BL/6（H2b）小鼠腹股沟部,制备小鼠皮下移植瘤。检测体内、外应用紫杉醇对Lewis肺癌细胞3LL的杀伤敏感性。在小鼠Lewis肺癌皮下移植瘤体内首先以紫杉醇化疗,随后以肿瘤疫苗3LL/GMCSF免疫;或反之,首先以肿瘤疫苗免疫,随后以紫杉醇化疗,观察肿瘤生长和小鼠生存状况,以及检测小鼠体内对肿瘤的特异性杀伤效率和免疫应答记忆反应。〖HT5W〗结果〖HT5"SS〗： 紫杉醇体外作用于3LL肿瘤细胞,24 h后在浓度为100 nmol/L时可使32.10 %的3LL肿瘤细胞发生死亡;但体内注射紫杉醇（5、10和25 mg/kg）不能使所有3LL荷瘤小鼠肿瘤消退。体内使用紫杉醇后应用3LL/GMCSF肿瘤疫苗,70%的荷瘤小鼠发生显著的肿瘤消退,与单纯化疗的小鼠相比生存时间明显延长（70.0 vs 27.5 d）; 化疗后应用肿瘤疫苗诱导了体内对3LL的特异性杀伤,第3天体内杀伤率达41.35%;同时,存活小鼠能抵抗2×104 3LL肿瘤细胞的再次攻击。接种3LL/GMCSF肿瘤疫苗后应用紫杉醇化疗却不能使肿瘤消退。〖HT5W〗结论： 〖HT5"SS〗化疗后应用肿瘤疫苗免疫可诱导出抗原特异性免疫效应,使荷瘤小鼠肿瘤消退并延长生存时间,为临床开展化疗后的肿瘤疫苗主动免疫提供了实验依据。     

GM-CSF膜修饰B16.F10黑素瘤细胞疫苗对小鼠种植肿瘤的抑制作用

目的: 研究粒细胞巨噬细胞集落刺激因子（granulocytemacrophage colony stimulating factor, GMCSF)膜修饰小鼠黑素瘤B16.F10细胞制备的疫苗对小鼠种植肿瘤的抑制作用。方法：采用生物素链亲合素GMCSF融合蛋白技术制备GMCSF膜修饰B16.F10黑素瘤细胞疫苗,将BALB/c小鼠随机分为GMCSF膜修饰B16.F10细胞疫苗组、GMCSF与B16.F10细胞混合疫苗组、B16.F10细胞疫苗组、GMCSF组、生理盐水组。各组于第1天和第7天分别进行免疫接种,第14天皮下注射0.2 ml B16.F10细胞（1×106个细胞）进行攻击,观察各组小鼠无瘤率和生存期;攻击后24 d 用ELISA法检测小鼠脾细胞INFγ分泌水平。结果：接受B16.F10细胞攻击后第60天和第90天,GMCSF膜修饰B16.F10细胞疫苗组小鼠均未成瘤,存活率为100%;GMCSF与 B16.F10细胞混合组无瘤率分别50%和40%,存活率分别为70%和40%;B16.F10细胞疫苗组无瘤率均为20%,存活率分别为80%和20%;GMCSF组和生理盐水组无瘤率为0,无小鼠存活。GMCSF膜修饰B16.F10细胞疫苗组的IFNγ分泌量比其他组明显升高（P<0.01）。结论：GMCSF膜修饰B16.F10肿瘤细胞疫苗可以激发BALB/c小鼠特异性抗肿瘤免疫反应,有效防止B16.F10肿瘤细胞的攻击。     

腺病毒介导的人GM——CSF基因转染瘤苗体内致瘤性降低的实验研究

目的:建立以腺病毒为载体的GM—CSF基因转染瘤苗,并对其体内抗肿瘤作用加以研究。方法:应用携带有人GM—CSF基因的重组腺病毒(R—Ad_5)载体转染BALB/C小鼠肝癌细胞株(H_(22)),体外应用酶联免疫吸附试验(ELISA法)检测GM—CSF表达水平,以GM—CSF基因转染的H_(22)细胞进行致瘤性研究。结果:(1)重组腺病毒载体能成功地介导GM—CSF基因转染H_(22)细胞并能持续有效表达26～31天,瘤苗的辐照处理并不明显影响GM—CSF表达水平。(2)GM—CSF基因转染瘤苗体内致瘤性显著降低。结论:该结果揭示了应用GM—CSF基因转染瘤苗进行肿瘤基因治疗的可行性,为进一步研究肿瘤的GM—CSF基因治疗打下了基础。     

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.     

异种肿瘤细胞疫苗抗肿瘤活性的研究

目的研究异种肿瘤细胞疫苗抗肿瘤免疫反应,从而达到抑瘤作用.方法采用福氏佐剂与人肺腺癌AGZY-138、人肝癌HepG2细胞分别混合研磨制成疫苗,小鼠腹部皮下多点注射免疫小鼠或治疗小鼠,定期测定瘤体,计算抑瘤率、生存率等.结果预防保护实验肿瘤接种第五周时,与对照组比较抑瘤作用显著,肿瘤治疗实验肿瘤接种第五周时,人肺癌AGZY-138疫苗对小鼠Lewis肺癌治疗作用与对照组比较有显著意义,而人肝癌HepG2疫苗治疗作用对小鼠H22肝癌作用不显著,与对照组比较无差异.结论用异种肿瘤细胞疫苗对小鼠进行主动免疫后,再接种肿瘤,肿瘤生长明显减慢.肺癌疫苗预防保护小鼠生存期延长.     

分泌mRANTES趋化因子的小鼠肝癌细胞的建立及其体内致瘤性的初步研究

目的：建立分泌mRNATES的小鼠肝癌细胞，并观察其体内致瘤性。方法：mRNATES cDNA被克隆入pBabe puro逆转录病毒载体，构建的重组逆转录病毒载体pBabe puro mRNATES转染包装细胞，嘌呤酶素抗性细胞培养上清感染小鼠肝癌细胞系Hepal-6，免疫组化检测Hepal-6、Hepal-6 mRNATES的mRNATES蛋白的表达。绘制Hepal-6 mRNATES与Hepal-6的生长曲线观察细胞的生长。琼脂糖凝胶打孔法体外观察Hepal-6 mRNATES分泌蛋白对小鼠脾细胞的趋化作用。观察Hepal-6 mRNATES体内致瘤性。结果：构建了重组逆转录病毒载体pBabe puro mRNATES,Hepal-6不表达mRNATES,Hepal-6 mRNATES表达mRNATES蛋白。Hepal-6 mRNATES与Hepal-6的生长曲线基本一样。Hepal-6 mRNATES分泌了对小鼠脾细胞有趋化作用的分子。Hepal-6 mRNATES体内致瘤性降低。结论：Hepal-6 mRNATES能产生mRNATES,mRANTES不改变细胞体外生长状况，Hepal-6 mRNATES产生的mRNATES有趋化活性，mRNATES能使Hepal-6 mRNATES致瘤性降低。     

细胞融合大鼠肝癌疫苗体内治疗和预防作用研究

目的 :观察大鼠 BERH - 2肝癌细胞与激活 B细胞的细胞融合大鼠肝癌疫苗对肿瘤的预防和治疗作用。方法 :应用 PEG将大鼠 BERH- 2肝癌细胞与激活 B细胞融合 ,制备细胞融合大鼠肝癌疫苗 ;部分肝癌疫苗免疫动物前经 6 0 Co照射 ;大鼠被肝癌疫苗免疫之前或之后 ,接种肝癌 BERH- 2细胞或组织块 ,观察疫苗对肝癌的预防和治疗作用。结果 :经细胞融合疫苗保护的大鼠可获 10 0 %无瘤生存 (8/8) ,而 HERH- 2或照射后 BERH- 2对照组大鼠均生长肿瘤死亡 (0 /8)。经皮下接种细胞融合肝癌疫苗治疗大鼠 ,肝内注射肝癌细胞的大鼠可获 85 %以上无瘤存活。照射后细胞融合肝癌疫苗与未照射的获得同样治疗效果。不经筛选的细胞融合疫苗也获相同治疗效果 ,而对照组大鼠均生长肿瘤后死亡。结论 :细胞融合肝癌疫苗对大鼠有预防和治疗作用 ,照射的细胞融合大鼠肝癌疫苗和不经筛选的融合细胞同样具有较好的治疗作用。     

B7基因修饰的肿瘤细胞疫苗体内外调控细胞因子水平的研究

我们率先在国内外报道了有关B7基因修饰肝癌细胞对其免疫原性和致瘤性的影响及B7基因修饰的肿瘤细胞疫苗(tumor cell vaccine,TCV)的体内、外抗肿瘤作用.我们的研究发现,在缺乏B7分子的小鼠肝癌细胞Hepal-6与细胞株中导入小鼠B7-1,B7-2基因,能使该肝癌细胞株的免疫原性大大增强,致瘤性完全消失.用丝裂霉素C(MMC)处理转染了B7-1,B7-2基因的小鼠肝癌细胞Hepal-6细胞株,制备成肿瘤细胞疫苗,其抗肿瘤作用明显增强,表现为对论动物的免疫模型起完全的免疫保护作用、对早期模型起部分治疗作用和     

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.     

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.     

Ad介导人AFP和IFN-у协同诱发抗小鼠肝癌免疫效应

背景与目的:原发性肝癌(hepatocellular carcinoma,HCC)是常见的恶性肿瘤之一,目前对HCC的治疗尚无行之有效的手段。本研究探讨腺病毒(Adenovirus,Ad)载体介导异种甲胎蛋白(Alpha-fetoprotein,AFP)和酌干扰素(Interferon-gamma,IFN-γ酌)的协同抗肝癌效应。方法:用RT-PCR(reverse transcri-ptase-polymerase chain reaction)方法克隆小鼠IFN-γ酌基因并构建复制缺损型腺病毒编码人AFP和小鼠IFN-γ酌联合表达载体(Ad-hAFP/IFN-γ酌)。皮内免疫C57BL/6小鼠7d后,取脾细胞行51Cr释放实验检测特异性细胞毒T淋巴细胞(Cytotoxic Tlymphocytes,CTLs)杀伤活性;或给免疫小鼠皮下接种Hepa1-6肝癌细胞,观察荷瘤小鼠成活情况。结果:51Cr释放实验显示,Ad-hAFP/IFN-γ酌免疫小鼠1周后其诱导产生的特异性CTL杀伤活性明显强于Ad-hAFP或Ad-IFN-γ酌单独免疫,在效∶靶比(E∶T)为10∶1时,Ad-hAFP/IFN-γ酌、Ad-hAFP和Ad-IFN-γ酌诱发的CTL杀伤率分别(43.8±5.5)%、(28.2±3.2)%和(12.8±1.9)%;30∶1时,为(79.6±6.4)%、(51.9±4.3)%和(15.6±2.3)%以及90∶1时(88.2±6.3)%、(62.5±4.8)%和(26.5±2.4)%。荷瘤试验表明,Ad-hAFP或Ad-IFN-γ酌单独免疫小鼠后1周接种5×106Hepa1-6肝瘤细胞,观察2个月,Ad-hAFP免疫组80%的小鼠荷瘤,Ad-IFN-γ酌免疫组小鼠则100%荷瘤;而Ad-hAFP/IFN-γ酌免疫小鼠在接种同样数量的Hepa1-6细胞,2个月无小鼠荷瘤,小鼠100%存活。结论:腺病毒载体介导异种AFP能有效地诱发针对小鼠AFP的特异性细胞免疫反应,IFN-γ酌能明显增强这种效应。     

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.     

Irreversible electroporation enhances immunotherapeutic effect in the off-target tumor in a murine model of orthotopic HCC

Irreversible electroporation (IRE) has been postulated to have an off-target effect on lesions not in the tumor-ablative field, possibly through heightened immunologic response. In this study, we evaluated whether combination IRE and immunotherapy would lead to increased tumor necrosis and T cell recruitment to both the treated tumors and tumors outside the local ablative field. An in vitro cell-IRE model was established to evaluate the ability of T lymphocytes (EL4 cell and HH cells) migration in response to Hepatocellular carcinoma (HCC) cells (Hepa1-6 and HepG2) with IRE treatment. An orthotopic HCC mouse model was established by implantation of 1mm^3 sections of Hepa1-6 tumor tissues into the right and left lobes of the liver. The Hepa1-6 cells and HepG2 cells with IRE treatment increased the migration ability of EL4 cell and HH cells, specifically when they were pretreated with immunotherapeutic agents in vitro. In the orthotopic HCC mouse model, IRE+immunotherapy treatment enhanced the necrosis and subpopulation of infiltrated CD8 positive cells, but attenuated the tumor associated inflammatory cells in both IRE target tumor tissues and IRE off-target tumor tissues from the mice with 4 weeks of immunotherapy following IRE. This study provided the evidence that combination of IRE and immunotherapy enhances tumor necrosis and immune responses, not only in the IRE-treated tumor but also in the off-target tumor.     

Autologous Fixed Tumor Vaccine: A Formulation with Cytokine-microparticles for Protective Immunity against Recurrence of Human Hepatocellular Carcinoma

We developed a tumor vaccine consisting of fixed hepatocellular carcinoma (HCC) cells/tissue fragments, biodegradable microparticles encapsulating granulocyte-macrophage-colony stimulating factor and interleukin-2, and an adjuvant. The vaccine protected 33% of syngeneic mice from HCC cell challenge. The vaccine containing human autologous HCC fragments showed essentially no adverse effect in a phase I/IIa clinical trial and 8/12 patients developed a delayed-type hyper-sensitivity (DTH) response against the fragments. Although 2 of 4 DTH-response-negative patients had recurrence after curative resection, the DTH-response-positive patients had no recurrence. The time before the first recurrence in the vaccinated patients was significantly longer than that in 24 historical control patients operated in the same department ( P <0.05). This formulation is a promising candidate to prevent recurrence of human HCC.     

Autologous fixed tumor vaccine: a formulation with cytokine-microparticles for protective immunity against recurrence of human hepatocellular carcinoma.

We developed a tumor vaccine consisting of fixed hepatocellular carcinoma (HCC) cells/tissue fragments, biodegradable microparticles encapsulating granulocyte-macrophage-colony stimulating factor and interleukin-2, and an adjuvant. The vaccine protected 33% of syngeneic mice from HCC cell challenge. The vaccine containing human autologous HCC fragments showed essentially no adverse effect in a phase I/IIa clinical trial and 8/12 patients developed a delayed-type hypersensitivity (DTH) response against the fragments. Although 2 of 4 DTH-response-negative patients had recurrence after curative resection, the DTH-response-positive patients had no recurrence. The time before the first recurrence in the vaccinated patients was significantly longer than that in 24 historical control patients operated in the same department (P < 0.05). This formulation is a promising candidate to prevent recurrence of human HCC.     

MiR-22 regulated T cell differentiation and hepatocellular carcinoma growth by directly targeting Jarid2

MiR-22 has been demonstrated to inhibits tumor growth in several cancers. However, its function in the tumor microenvironment is still unclear, especially for T cell differentiation. Here, miR-22 expression in the circulating T cells from hepatocellular carcinoma (HCC) patients and healthy controls was analyzed with quantitative polymerase chain reaction (qPCR). Diethylnitrosamine (DEN)/phenobarbital (PB)-mediated primary HCC and Hepa1-6 subcutaneous tumor mouse models were established and subjected to lenti-miR-22 injection. Mice immunoreconstituted with miR-22-overexpressing T cells were employed to investigate the antitumor effect of miR-22 in mice. Luciferase assay, immunofluorescent staining, in vitro Th17 cell differentiation assay, and rescue experiments were employed to investigate the mechanism underlying the miR-22-mediated regulation of Th17 cell differentiation and liver tumor growth. Results confirmed the dramatic downregulation of miR-22 expression in malignant tissues and circulating T cells from patients with HCC. MiR-22 expression correlated with good prognosis of patients. Overexpression of miR-22 impaired the DEN/PB-induced primary HCC formation and the growth of Hepa1-6 subcutaneous tumors by promoting Th17 differentiation. Injection of miR-22-overexpressing T cells in irradiated mice resulted in the inhibition of Hepa1-6 subcutaneous tumor growth via Th17 differentiation promotion. MiR-22 could directly bind to Jarid2, which played an important role during the miR-22-mediated regulation of Th17 differentiation. Taken together, our study expands the understanding of miR-22 function and provides a therapy target for HCC.     

Anti-tumor immunity induced by an anti-idiotype antibody mimicking human Her-2/neu

Our goal is to apply an anti-idiotype (Id) antibody based vaccine approach for the treatment of Her-2/neu-positive human cancer. Amplification and/or over-expression of Her-2/neu occur in multiple human malignancies and are associated with poor prognosis. Her-2/neu proto-oncogene is a suitable target for cancer immunotherapy. We have developed and characterized a murine monoclonal anti-Id antibody, 6D12 that mimics a specific epitope of Her-2/neu and can be used as a surrogate antigen for Her-2/neu. In this study, the efficacy of 6D12 as a tumor vaccine was evaluated in a murine tumor model. Immunization of immunocompetent C57BL/6 mice with 6D12 conjugated to keyhole limpet hemocyanin and mixed with Freund’s adjuvant or 6D12 combined with the adjuvant QS21 induced anti-6D12 as well as anti-Her-2/neu immunity. Her-2/neu-positive human breast carcinoma cells, SK-BR-3 reacted with immunized mice sera as determined by ELISA and flow cytometry. Flow cytometry analysis also demonstrated strong reactivity of immunized mice sera with human Her-2/neu transfected EL4 cells (EL4-Her-2), but no reactivity with nontransfected parental EL4 cells. Antibody dependent cellular cytotoxicity against EL4-Her-2 cells was also observed in presence of immune sera. Mice immunized with 6D12 were protected against a challenge with lethal doses of EL4-Her-2 cells, whereas no protection was observed against parental EL4 cells or when mice were immunized with an unrelated anti-Id antibody and challenged with EL4-Her-2 cells. These data suggest that anti-Id 6D12 vaccine can induce protective Her-2/neu specific antitumor immunity and may serve as a potential network antigen for the treatment of patients with Her-2/neu-positive tumors. Asim Saha and Smarajit Pal contributed equally to this work. This work was presented as abstract in the San Antonio Breast Cancer Symposium, 2005. Breast Cancer Research and Treatment 94, supplement 1:4093.     

Induction of immune tolerance toward tumor-associated-antigens enables growth of human hepatoma in mice.

Adoptive transfer of immunity against hepatitis B surface antigen (HBsAg) was previously shown to facilitate suppression of experimental human hepatocellular carcinoma (HCC) expressing HBsAg in athymic mice. We have shown that oral tolerance induces antigen‐specific immune suppression of HBsAg by feeding hepatitis B virus (HBV) antigens. In the present study we evaluated the effect of oral tolerance induction toward HBV or HCC antigens on the growth of experimental HCC‐expressing HBsAg in mice. Tolerance induction was induced in mice by 5 oral feedings of 1 μg HBV antigens or HCC‐extracted proteins (50 μg protein) before vaccination with recombinant HBsAg. Splenocytes (2 × 10⁶) from these mice were transferred to sublethally irradiated athymic BALB/c mice previously transplanted subcutaneously with 10⁷ human hepatoma Hep3B cells. Adoptive transfer of splenocytes immunized toward HBsAg prevented tumor growth. At 4 weeks after splenocyte transplantation, tumor volume and serum alpha‐fetoprotein (AFP) levels in athymic mice transplanted with splenocytes immunized to HBsAg were undetectable as compared with 1,048 ± 738 mm³ and 2,500 ± 1,431 ng/ml in recipients of naïve splenocytes (p < 0.0001). Mice receiving splenocytes tolerized toward Hep3B cells, as manifested by reduced serum HBs antibody levels, reduced HBV‐specific stimulation index and reduced HBV‐specific‐IFNγ spot‐forming cells, had early tumor growth evident by elevated AFP serum levels, weight loss and mortality, which were suppressed at 6 weeks. Mice transplanted with splenocytes tolerized toward HBV antigens did not have direct evidence of tumor growth. Induction of oral tolerance toward HCC‐extracted proteins enabled transient tumor growth in this model. This effect was mediated through downregulation of the anti‐HBV immune response. © 2002 Wiley‐Liss, Inc.