GM—CSF基因修饰的肿瘤细胞疫苗对荷瘤小鼠的抗肿瘤作用

目的研究GM-CSF基因修饰的肿瘤细胞作为瘤苗的可行性.方法通过逆转录病毒载体,将小鼠GM-CSF基因导入EL-4淋巴瘤细胞中,研究EL-4/GM-CSF在同系C57BL/6小鼠中的成瘤性及其诱导抗肿瘤免疫的效果.结果EL-4/GM-CSF细胞在小鼠中的成瘤性下降,50%小鼠无瘤生存.射线灭活的EL-4/GM-CSF瘤苗能有效地保护野生型肿瘤细胞的攻击,在肿瘤生长的早期对实验性荷瘤小鼠进行治疗,能延长荷瘤宿主的存活时间(33.1±1.8)与对照组EL-4/Wt(23.2±1.5天)比差异有显著性(P＜0.01).基因修饰的瘤苗作用明显增强.结论GM-CSF基因修饰的肿瘤疫苗可诱导较强的抗肿瘤免疫反应,导致肿瘤的部分根除,本实验为基因修饰的肿瘤疫苗的临床应用提出了一定的实验依据.     

HSA基因转染小鼠淋巴细胞EL-4诱导宿主的体内抗瘤效应

将热稳定抗原(Heat-stable Antigen,简称HSA)的cDNA与质粒载体(PcDNA3)连接,构建成真核表达载体,通过电穿孔的方法将重组质粒导入到小鼠淋巴瘤细胞EL-4中,使其表达抗性基因和HSA分子,通过高剂量G418(400μg/ml)选择培养和有限稀释法克隆,获得高比例表达HSA的阳性细胞克隆,以提供活化T细胞所必需的协同刺激信号,从而诱导宿主体内有效的抗肿瘤免疫应答。实验发现:表达HSA的EL-4淋巴瘤细胞在同系小鼠(C57BL/6)体内的致瘤性明显较野生型肿瘤弱。HSA~ EL-4瘤细胞经丝裂霉素灭活后,腹腔免疫同系小鼠后可获得对低剂量(2×10~3/鼠)野生型瘤细胞EL-4攻击的免疫保护效应。用HSA~ 瘤细胞灭活后作为瘤苗治疗早期带瘤动物显示一定的治疗效果。     

HSA基因转染小鼠淋巴瘤细胞EL-4诱导的抗瘤效应

本文将热稳定抗原(HSA)的CDNA与质粒PcDNA3连接,构建成真核表达体,通过电穿孔的方法将重组质粒导入不表达HSA的淋巴瘤细胞EL-4中,使其表达抗性基因和HSA分子,通过高剂量G418(400μg/ml)选择培养和流式细胞仪免疫荧光染色检测,并进一步通过有限稀释法克隆到高表达HSA的单细胞克隆,用含低剂量G418(200μg/ml的RP-MI1640完全培养液维持培养,以维持转染瘤细胞上的HSA的表达,从而提供活化T细胞必要的协同刺激信号,以诱导出有效的抗肿瘤免疫应答.实验观察了高表达HSA淋巴瘤细胞EL-4在体内诱导的抗癌效应及其提高肿瘤免疫原性的作用.结果表明,用丝裂霉素C灭活的HSA~ 癌细胞作为瘤苗早期治疗野生型瘤细胞EL-4接种小鼠的动物模型显示     

IL-12协同B7-1转基因细胞增强C57BL/6小鼠的抗肿瘤免疫

目的:应用逆转录病毒构建IL-12、B7-1表达载体,以研究基因修饰的肿瘤细胞的癌疫苗作用.方法:将两种表达载体分别转染EL-4胸腺瘤细胞,使该细胞能表达分泌B7-1或IL-12,并研究了该基因导入细胞的抗肿瘤免疫效果.结果当接种了EL-4/IL-12转染细胞后,在C57BL/6同系鼠中其基因导入细胞的肿瘤原性比较EL-4/Wt和EL-4/Neo组明显减少(P＜0.01),在EL-4/IL-12组的肿瘤被排斥后,实验动物体内诱发了抗EL-4/Wt的全身性、保护性免疫,用51Cr释放测定法证明有一个较强的抗EL-4/Wt和一个较弱的抗同系Lewis肿瘤细胞的CTL活性,体内淋巴细胞消除分析的结果提示减少的肿瘤原性主要与CD4+、CD8+和NK细胞有关.用EL-4/IL-12基因转染的瘤细胞进行疫苗治疗比较用EL-4/Neo瘤细胞作疫苗治疗能更加有效地延缓已建立的EL-4/Wt肿瘤的生长(P＜0.005),EL-4/IL-12和EL-4/B7-1基因联合转染组比用单一的转基因细胞增强了治疗效果(P＜0.005).结论:研究结果提示应用IL-12进行血液肿瘤的治疗是有效的,IL-12和B7-1联合使用在未来人类癌症的治疗中有一定的应用前景.     

IL—12协同B7—1转基因细胞增强C57BL／6小鼠的抗肿瘤免疫

目的应用逆转录病毒构建IL-12、B7-1表达载体,以研究基因修饰的肿瘤细胞的癌疫苗作用.方法将两种表达载体分别转染EL-4胸腺瘤细胞,使该细胞能表达分泌B7-1或IL-12,并研究了该基因导入细胞的抗肿瘤免疫效果.结果当接种了EL-4/IL-12转染细胞后,在C57BL/6同系鼠中其基因导入细胞的肿瘤原性比较EL-4/Wt和EL-4/Neo组明显减少(P＜0.01),在EL-4/IL-12组的肿瘤被排斥后,实验动物体内诱发了抗EL-4/Wt的全身性、保护性免疫,用51Cr释放测定法证明有一个较强的抗EL-4/Wt和一个较弱的抗同系Lewis肿瘤细胞的CTL活性,体内淋巴细胞消除分析的结果提示减少的肿瘤原性主要与CD4+、CD8+和NK细胞有关.用EL-4/IL-12基因转染的瘤细胞进行疫苗治疗比较用EL-4/Neo瘤细胞作疫苗治疗能更加有效地延缓已建立的EL-4/Wt肿瘤的生长(P＜0.005),EL-4/IL-12和EL-4/B7-1基因联合转染组比用单一的转基因细胞增强了治疗效果(P＜0.005).结论研究结果提示应用IL-12进行血液肿瘤的治疗是有效的,IL-12和B7-1联合使用在未来人类癌症的治疗中有一定的应用前景.     

用B7~ 瘤细胞诱导抗肿瘤CTL及其杀伤活性的测定

研究利用脂质体转染的方法,将小鼠B7基因导入C57BL小鼠大肠癌细胞株CMT93细胞(弱免疫原性),用800μg/ml的C418筛选得到阳性克隆,免疫组织化学检测发现B7分子得到充分表达,主要以细胞膜染色为主,也有部分细胞浆着色.将5×10~6B7~ CMT93细胞接种于C57BL小鼠背部皮下,以相同细胞数的野生型瘤细胞接种为阴性对照.结果发现实验组小鼠(n=4)第2周开始肿瘤的体积逐渐缩小,至第4周未肿瘤全部消失,而对照组肿瘤呈进行性生长(n=3),至第4周未肿瘤大小为(1.7654±0.4963)cm~2(长径×短径).实验组与对照组相比,有显著性差异(P<0.001).用B7~ CMT93瘤细胞致敏小鼠后再接种野生型的CMT93瘤细胞,小鼠全部不成瘤(n=4),未致敏小鼠除1只未成瘤外,余     

GM-CSF和多种细胞因子基因转导系统及其抗肿瘤免疫效应的研究

为了增强免疫基因治疗瘤菌诱导机体抗肿瘤系统免疫效应,我们应用逆病毒中介基因转移技术,将IL-2、IL-4、IL-6、IL-7、IFN-α、B7-1、TNF-α、GM-CSF等多种细胞因子基因导入肿瘤细胞,证实了这些基因修饰的肿瘤细胞.由于多种细胞因子基因的导入,诱导宿主抗肿瘤系统免疫能力明显增强.在此基础上,我们为了开发增强宿主免疫的肿瘤基因治疗新方案,构建了可以表达双价细胞因子GM-CSF、TNF-α、IL-4的逆病毒载体的基因修饰瘤苗.通过接种放射线灭活的分泌GM-CSF和IL-4细胞因子的肿瘤细胞即细胞因子肿瘤疫苗,来诱导有效地抗肿瘤系统免疫功能.应用构建的双价逆病毒载体和逆病毒中介基因转移技术,对肺癌、脑肿瘤小鼠模型进行了双价细胞因子基因瘤苗的抗肿瘤免疫增强效果和     

肿瘤模型中B7-H4和BTLA的异常表达

目的:通过检测肿瘤组织和肿瘤抗原诱导的小鼠脾脏巨噬细胞B7-H4表达、同时检测荷瘤小鼠T细胞BTLA的表达,以进一步探讨这一对新的负免疫调节分子在肿瘤免疫逃逸机制中的作用。方法:应用RT-PCR检测体外培养肿瘤细胞株3LL和Renca、荷瘤后小鼠肿瘤组织B7-H4mRNA以及荷瘤小鼠T细胞BTLA mRNA表达的改变;应用流式细胞术检测荷瘤小鼠脾脏巨噬细胞和肿瘤可溶性抗原诱导的正常小鼠脾脏巨噬细胞B7-H4表面蛋白表达的改变;应用免疫组化技术检测荷瘤后小鼠肿瘤组织B7-H4表面蛋白表达的改变。结果:在体外培养的肿瘤细胞株3LL和Renca上未检测到B7-H4mRNA的表达,小鼠成瘤后肿瘤组织和脾脏巨噬细胞在mRNA水平和蛋白质水平上均高表达B7-H4。另外荷瘤小鼠的T细胞较正常小鼠T细胞BTLA的表达明显增高。在体外肿瘤抗原刺激下,正常小鼠脾脏巨噬细胞B7-H4表达量明显上升;而用正常同样组织来源抗原刺激时,正常小鼠脾脏巨噬细胞B7-H4表达量未见显著改变。结论:B7-H4和BTLA这对协同刺激分子的异常表达可能在肿瘤逃逸免疫应答过程中起调节作用。     

EB病毒在SCID小鼠体内诱发人B淋巴细胞肿瘤

目的:通过动物体内试验研究EB病毒(EBV)对人正常细胞的致瘤性,并检测我国正常人群对EBV的易感性,试图建立EBV诱发人淋巴细胞肿瘤模型。方法:在严重联合免疫缺陷动物即SCID小鼠体内移植健康成人外周血淋巴细胞(PBL),每鼠腹腔接种1×108个PBL。对接种VCA/IgA阴性献血员PBL的动物,移植后1周内经腹腔注射B95-8标准株EBV悬液作为实验感染,而接种VCA/IgA阳性献血员PBL的动物不再进行实验感染。结果:在接受12名健康成人PBL移植并感染EBV的19只SCID小鼠中,肿瘤诱发率分别为91.7%(11/12名)和84.2%(16/19只鼠)。诱发瘤常见于小鼠腹腔后壁和纵隔,具有侵袭性和致死性,患瘤小鼠平均存活时间65.5天。EBV诱发瘤是结节状实体瘤,显微镜下观察肿瘤细胞呈大裂—无裂混合细胞。组织病理学和免疫病理学研究表明,肿瘤类型是人源B细胞性恶性淋巴瘤。诱发瘤原位分子杂交显示肿瘤细胞核内存在EB病毒小核酸分子EBER-1和人类基因组Alu序列。电子显微镜观察肿瘤细胞核内存在EB病毒颗粒。肿瘤细胞表达EB病毒BZLF1蛋白阳性。结论:SCID/人淋巴细胞嵌合体是研究EBV感染和致瘤性的敏感动物模型,且获得了EBV引起人类正常细胞在体内发生肿瘤的直接依据。因而证实了EBV对人类细胞的致瘤作用,进一步明确机体免疫缺陷因素在肿瘤发生中起重要作     

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     

ANTITUMOR EFFECTS INDUCED BY B7-1 GENE MODIFIED EL-4 LYMPHOMA COOPERATED WITH IL-2 IN VIVO AND IN VITRO

ＡＮＴＩＴＵＭＯＲＥＦＦＥＣＴＳＩＮＤＵＣＥＤＢＹＢ７１ＧＥＮＥＭＯＤＩＦＩＥＤＥＬ４ＬＹＭＰＨＯＭＡＣＯＯＰＥＲＡＴＥＤＷＩＴＨＩＬ２ＩＮＶＩＶＯＡＮＤＩＮＶＩＴＲＯＷｕＡｉｍｉｎ武爱民ＺｈａｎｇＹｕｅｊｉａｎ张跃建ＱｉｎＨｕｉｌｉａｎ秦慧...     

GM-CSF gene or B7-1 gene modified murine EL-4 cells vaccine

Since 1990, gene transduced tumor vaccine has been studied. Many articles reported that tumor cells transduced with some cytokine or costimulatory molecule could induce system antitumor immunity[1,2] In this study, EL-4 lymphoma was transduced with recombinant retrovirus containing the murine GM-CSF gene and B7-1 gene, respectively. The effect of gene transduction on antitumor immunity was investigated.MATERIALS AND METHODSMice and Cell Lines Female C57BL/6 mice were bought from …     

ANTITUMOR IMMUNITY AND VACCINE EFFECT INDUCED BY IL—12 SYNERGIZES B7—1 GENE TRANSFECTED CELLS

Cytokines play an crucial role in the induction of antitumor immunity. It have been demonstrated that cytokines such as IL-2, IL-4, IL-12 could stimulate immunity response in many basic and clinical experiment[1-3]. Interleukin 12 (IL-12) is a heterodimeric cytokine which consists of p40 and p35 subunits. It stimulates the proliferation and activation of T lymphocyte and other killer cells and induces the production of IFN-g by these cells[4, 5]. IL-12 promotes T helper type 1 responses.…     

Effects of survivin antagonists on growth of established tumors and B7-1 immunogene therapy

BACKGROUND: Survivin, a member of the inhibitor of apoptosis (IAP) protein family, is detectable in most types of cancer, and its presence is associated with a poor prognosis. We determined the effects of gene-based therapies that inhibit survivin function in a mouse tumor model. METHODS: Using five to six mice per treatment group, we injected tumors derived from mouse EL-4 thymic lymphoma cells with plasmids encoding antisense survivin, a dominant-negative mutant survivin, and the T-cell costimulator B7-1. Expression of endogenous survivin and the proteins encoded by the injected plasmids were examined by immunohistochemical staining of tumor sections and by western blot and flow cytometry analyses of isolated tumor cells. Tumor growth, the generation of antitumor cytotoxic T-lymphocyte (CTL) activity, apoptosis, and the contribution of leukocyte subsets to antitumor activity were measured. All statistical tests were two-sided. RESULTS: Large (1.0-cm diameter) tumors had approximately 10-fold more survivin than small (0.2-cm diameter) tumors. At 28 days after injection, antisense and dominant-negative mutant survivin plasmids statistically significantly inhibited the growth of both small (P =.006 and P =.0018, respectively) and large (P<.001 for both plasmids) EL-4 tumors compared with tumors injected with empty plasmid. The growth of large tumors was further inhibited by intratumoral injection with antisense survivin and B7-1 (P =.004); thus, inhibition of survivin expression renders large tumors susceptible to B7-1-mediated immunotherapy. Mice whose tumors were completely eradicated by injection of B7-1 remained tumor free for 26 days after re-injection with EL-4 cells (when the experiment ended). Compared with tumors injected with empty plasmid, tumors injected with survivin-based plasmids had increased apoptosis, and animals bearing such tumors generated more antitumor CTLs. CONCLUSION: Intratumoral injection of plasmids that block survivin expression and stimulate the generation of tumor-specific CTLs may be beneficial for the treatment of large lymphomas.     

树突状细胞与髓性白血病的免疫治疗 *

目的：我们应用逆转录病毒构建了ＩＬ－１２,Ｂ－７和ＧＭ－ＣＳＦ表达载体,以研究基因修的肿瘤细胞的癌疫苗作用。方法：将３种表达载体分别转染ＥＬ－４胞腺瘤细胞并研究了该基因导入细胞的抗肿瘤免疫效果。结果：当接种子ＥＬ４／ＩＬ－１２细胞后,在Ｃ５７ＰＬ／６同系鼠中其基因导入细胞的肿瘤原性比较ＥＬ４／Ｗｔ和ＥＬ－４／Ｎｅｏ组明显减少（Ｐ〈０．０１）。在ＥＬ４／ＩＬ－１２被排斥后,体内试验中诱发了实验动物抗     

Inhibitory effects of B cells on antitumor immunity

B-cell functions in antitumor immunity are not well understood. In this study, we evaluated the role of B cells in the development of antitumor immunity using Friend murine leukemia virus gag-expressing mouse EL-4 (EL-4 gag), D5 mouse melanoma, or MCA304 mouse sarcoma cells. To screen tumors for susceptibility to B-cell-deficient immune environments, spleen cells from naive C57BL/6 [wild-type (WT)] and B-cell knockout (BKO) mice were cultured with irradiated tumor cells in vitro. When cells were stimulated with EL-4 gag or D5 (but not MCA304 tumors), IFN-gamma production from CD8 T cells and natural killer cells was markedly decreased in WT compared with BKO cultures. IFN-gamma production was correlated with CD40 ligand expression on the tumor and inversely with interleukin-10 (IL-10) production by B cells. Sorted WT B cells produced more IL-10 than CD40 knockout (CD40KO) B cells when cocultured with EL-4 gag or D5 (but not MCA304). IFN-gamma production by BKO cells was reduced by the addition of sorted naive WT B cells (partially by CD40KO B cells) or recombinant mouse IL-10. In vivo tumor progression mirrored in vitro studies in that WT mice were unable to control tumor growth whereas EL-4 gag and D5 tumors (but not MCA304) were eliminated in BKO mice. Robust in vivo antitumor CTLs developed only in BKO tumor-challenged mice. Our studies provide the first mechanistic basis for the concept that B-cell depletion could therapeutically enhance antitumor immune responses to certain tumors by decreasing IL-10 production from B cells.     

Human Flt3 ligand from Pichia pastoris inhibits growth of lymphoma and colon adenocarcinoma in mice

Potent effects of Flt3 ligand (FL) on the development of the immune system have generated much interest in application of FL in cancer immunotherapy. OBJECTIVE: To evaluate the effects of Pichia pastoris secreted rhFL on the growth of mouse EL-4 lymphoma and C26 colon adenocarcinoma injected in syngeneic mice for the first time. METHODS: Mice were placed into one of two treatment groups. 2 x 10(5) EL-4 or C26 cells were injected subcutaneously (SC.) into mice on day 0. Group 1 received subcutaneous PBS injections from Day -7 to Day 14 and group 2 received subcutaneous rhFL injections at 30 microg/day from Day -7 to Day 14. Serial tumor areas were measured. On Day 22, mice from each group were sacrificed, and weight of tumors and spleens were evaluated. Data analysis used Student t tests. RESULTS: Pichia pastoris secreted rhFL resulted in tumor growth delay for both EL-4 lymphoma and C26 colon adenocarcinoma compared with control (P < 0.01). Tumors from rhFL-treated mice were smaller (P < 0.01) than controls while spleens larger (P < 0.01) than controls. Histological examination of tumor sections revealed an obvious increase in regions composed largely of infiltrating cells in the rhFL-treated tumors. Infiltrating cells could be detected in clusters among tumors from mice treated with rhFL whereas these cells were only occasionally detected in sections of control tumors. CONCLUSION: Treatment of rhFL expressed from Pichia pastoris resulted in an antitumor response against EL-4 and C26 tumors injected in syngeneic mice.     

Induction of systemic antitumor immunity by gene transfer of mammalian heat shock protein 70.1 into tumors in situ.

Heat shock proteins (hsps) chaperone cytosolic peptides, forming complexes that stimulate antitumor immunity. Hsps facilitate signal 1 in the two-signal model of T-cell costimulation, whereas cell adhesion molecules such as B7.1 provide secondary (signal 2) costimulatory signals. B7.1 gene transfer into tumors in situ has been shown to eradicate small (<0.3 cm in diameter) tumors in mice, and induce systemic antitumor immunity, but is ineffective against larger tumors. We examine whether mammalian hsps, as facilitators of T-cell costimulation, also exhibit this ability, and whether simultaneously stimulating both signal 1 (hsp-facilitated antigen presentation) and signal 2 (B7.1-mediated costimulation) enhances antitumor immunity compared to that achieved with either monotherapy. Prophylactic vaccination of mice with an hsp preparation from an EL-4 lymphoma weakly retarded tumor growth, to the same extent as that achieved with a single EL-4-derived peptide (AQHPNAELL), previously shown to induce antitumor immunity establishing that a preparation of EL-4 hsp-peptide complexes has antitumor activity. Here we show that injection of rat hsp70.1 into mouse tumors in situ causes the complete eradication of tumors, and generates potent systemic antitumor immunity mediated by CD4+ and CD8+ T cells. Unexpectedly, simultaneous gene transfer of hsp70.1 and B7.1 compromised the efficacy of hsp-mediated tumor rejection--a problem which could be partially overcome by the timed delivery of hsp70.1 and B7.1. Thus, gene transfer of hsp70 into tumors can be employed to generate potent systemic antitumor immunity, but further consideration is required if this approach is to be successfully combined with immunotherapies employing other T-cell costimulators.     

GM-CSF及B7-1基因修饰的肿瘤细胞疫苗抗肿瘤的研究

目的：研究ＧＭ－ＣＳＦ及Ｂ７－１基因修饰的肿瘤细胞作为瘤苗的有效性。方法：我们将小鼠ＧＭ－ＣＳＦ及ＣＤ８０基因通过逆转录病毒载体分别导入ＥＬ－４淋巴瘤细胞中,进而研究了ＥＬ－４／ＧＭ－ＣＳＦ及ＥＬ－４／Ｂ７－１在同系Ｃ５７Ｂ习中的成瘤性及其诱导抗肿瘤免疫的效果。结果：转Ｂ７－１基因的肿瘤细胞诱发了ＣＤ８０的高表达。转基因的肿瘤细胞在同源小鼠中的成瘤性下降,免疫原笥增强。在肿瘤生长的早期对实验性荷瘤