丙肝核心抗原-CD40L胞外段真核表达载体的构建及其免疫原性分析

目的构建丙肝核心抗原-CD40L胞外段融合蛋白真核表达载体,并探讨其免疫原性。方法应用基因重组技术在原有载体的基础上构建真核表达载体pcDNA3.1-core-CD40L并加以鉴定。该表达质粒肌肉内注射免疫小鼠,ELISA法检测小鼠外周血中抗丙肝核心抗体,流式细胞仪检测小鼠外周血T淋巴细胞亚型,real time PCR法检测外周血单个核细胞内细胞因子,CTL杀伤实验检测小鼠脾淋巴细胞的杀伤活性。结果构建了真核表达载体pcD-NA3.1-core-CD40L,该载体能诱发小鼠产生高滴度的抗丙肝核心抗原的抗体,流式和real time结果证实该质粒能诱使小鼠T淋巴细胞由T0期向Th1和Th2转换,并以Th1为主,CTL杀伤结果显示该表达质粒能诱使小鼠产生高水平的细胞杀伤能力。结论成功构建了真核表达质粒pcDNA3.1-core-CD40L,该质粒能够在小鼠体内正确表达,并能诱发高水平的细胞杀伤活性。     

氧化型甘露聚糖修饰的LL/2c肿瘤细胞疫苗诱导Th1免疫反应

目的：观察氧化型甘露聚糖修饰的LL／2c肿瘤细胞疫苗(Oxidative mannan-conugated LL/2c,ox-ML)能否诱导Th1抗瘤免疫反应。方法：乙醇固定的LL/2c细胞(fixed LL／2c,f—L)、ox—M—L腹腔免疫小鼠,取脾脏制备T淋巴细胞悬液,采用ELISA检测体外刺激的T细胞INF-γ、IL-4分泌,^51Cr释放实验观察CTL。(cytotoxic T lymphocytes,CTL)杀伤活性。结果：ox—M—L免疫小鼠的T细胞经丝裂霉素C预处理的LL／2c体外刺激,其INF-γ分泌显著提高：^51Cr释放实验显示出对LL／2c细胞特异性的CTL杀伤活性,且这种杀伤活性具有CD8 T细胞的依赖性：未修饰的LL／2c免疫小鼠的T细胞诱导了较高的IL-4分泌,但未显示出CTL杀伤活性。结论：LL／2c肿瘤细胞作为抗原,经氧化型甘露聚糖修饰有效的诱导了Th1类型的抗瘤免疫反应。     

人SART 3基因疫苗对荷瘤小鼠的免疫杀伤作用

目的研究表达人T细胞识别的鳞状细胞癌抗原3（SART3）基因的DNA疫苗在小鼠体内对表达该基因肿瘤细胞的免疫杀伤作用。方法构建表达人SART3基因的C3H小鼠骨肉瘤细胞LM8-SART3，将其接种到C3H小鼠成瘤，比较疫苗治疗组和空载体对照组中肿瘤的生长情况，取小鼠淋巴细胞检测免疫反应活性并行病理切片镜下比较。结果荷瘤小鼠经疫苗注射后肿瘤生长延缓，免疫反应活性与淋巴细胞数量有关，镜下可见肿瘤细胞坏死并淋巴细胞浸润。结论表达人SART3基因的DNA疫苗能诱导小鼠免疫杀伤肿瘤细胞，抑制表达该基因的肿瘤细胞在小鼠体内生长。     

基于人／鼠嵌合模型的人黑色素瘤mage-3基因疫苗的免疫学作用

目的：利用人／鼠嵌合模型评价人黑色素瘤基因mage-3基因疫苗的免疫效果。方法：建立并鉴定Trimera动物模型，并用重组质粒mage-3／pCI-neo作为基因疫苗对其进行免疫。检测免疫动物脾细胞CTL的杀伤活性和血清中mage-3特异性抗体。结果：构建的Trimera模型脾脏和腹腔中出现了大量的人淋巴细胞。接种后，Trimera模型体内出现了效价为1：256的mage-3特异抗体。免疫动物CTL体外杀伤实验显示，注射基因疫苗的Trimera小鼠脾脏淋巴细胞对靶细胞LB373的最大杀伤率为50％左右。而对照小鼠只有10％以下的杀伤水平。结论：mage-3是一种理想的肿瘤疫苗，在人源化动物模型中能激发出特异的细胞和体液免疫，对共享mage-3抗原的各种肿瘤细胞的临床治疗提供了实验依据。     

表达新疆出血热病毒S基因片段的重组腺病毒特异性CTL功能测定

目的 通过表达新疆出血热病毒（XHFV）S基因片段的重组腺病毒特异性细胞毒性T淋巴细胞（CTL）功能测定，探求由XHFVS基闪片段编码的核衣壳蛋白作为抗原诱导的特异性CTL细胞对蓖组腺病毒致敏的靶细胞杀伤能力大小。方法 PCR扩增XHFVS基因的cDNA片段，将扩增后的cDNA片段克隆入腺病毒自主载体，使其成为重组腺病毒，用重组腺病毒感染Balb／C小鼠后，利用非放射性乳酸脱氰酶（LDH）释放法测定重组腺病毒的特异性CTL功能。结果 在一定比例范围内，效应细胞与靶细胞的比例越高，持异性CTL％越高。结论 由XHFVS基因片段编码的核衣壳蛋白抗原诱导的特异性CTL细胞，能特异性地杀伤重组腺病毒致敏的靶细胞；证实由腺病毒自主载体本身所表达的一些蛋白质也可诱导细胞免疫，由该载体所引发的细胞免疫对疫苗接种不利。     

表达新疆出血热病毒S基因片段的重组腺病毒特异性CTL功能测定

目的通过表达新疆出血热病毒(XHFV)S基因片段的重组腺病毒特异性细胞毒性T淋巴细胞(CTL)功能测定,探求由XHFVS基因片段编码的核衣壳蛋白作为抗原诱导的特异性CTL细胞对重组腺病毒致敏的靶细胞杀伤能力大小。方法PCR扩增XHFVS基因的cDNA片段,将扩增后的cDNA片段克隆入腺病毒自主载体,使其成为重组腺病毒,用重组腺病毒感染Balb/c小鼠后,利用非放射性乳酸脱氢酶(LDH)释放法测定重组腺病毒的特异性CTL功能。结果在一定比例范围内,效应细胞与靶细胞的比例越高,特异性CTL%越高。结论由XHFVS基因片段编码的核衣壳蛋白抗原诱导的特异性CTL细胞,能特异性地杀伤重组腺病毒致敏的靶细胞;证实由腺病毒自主载体本身所表达的一些蛋白质也可诱导细胞免疫,由该载体所引发的细胞免疫对疫苗接种不利。     

基于人/鼠嵌合模型的人黑色素瘤mage-3基因疫苗的免疫学作用

目的 利用人 /鼠嵌合模型评价人黑色素瘤基因 mage-3基因疫苗的免疫效果. 方法 建立并鉴定 Trimera动物模型,并用重组质粒 mage-3/pCI neo作为基因疫苗对其进行免疫.检测免疫动物脾细胞 CTL的杀伤活性和血清中 mage-3特异性抗体. 结果 构建的 Trimera模型脾脏和腹腔中出现了大量的人淋巴细胞.接种后, Trimera模型体内出现了效价为 1 256的 mage-3特异抗体.免疫动物 CTL体外杀伤实验显示,注射基因疫苗的 Trimera小鼠脾脏淋巴细胞对靶细胞 LB373的最大杀伤率为 50%左右,而对照小鼠只有 10%以下的杀伤水平. 结论 mage-3是一种理想的肿瘤疫苗,在人源化动物模型中能激发出特异的细胞和体液免疫,对共享 mage-3抗原的各种肿瘤细胞的临床治疗提供了实验依据.     

稳定表达bcr-abl融合基因片段的鼠SP2/0细胞系的建立

为了建立稳定表达bcr-abl融合基因片段的SP2/0细胞系,从重组克隆载体pGEMbcr-abl中酶切出bcr-abl融合基因片段,并将其亚克隆进逆转录病毒载体pLXSN中。脂质体介导重组逆转录病毒载体pLXSNbcr-abl转染包装细胞PT67,采用G418筛选后获得稳定产病毒的包装细胞。收集病毒感染NIH/3T3细胞,加G418筛选后进行逆转录病毒滴度的测定,计算病毒效价为2×107CFU/ml。结果表明,收集病毒上清感染SP2/0细胞(H-2d),经G418筛选获得了稳定表达bcr-abl融合基因片段的SP2/0细胞株。经特异性PCR扩增和RT-PCR反应扩增,从基因组整合和基因表达水平证实获得了能稳定表达bcr-abl融合基因片段的鼠SP2/0细胞系。结论:成功建立了表达bcr-abl融合基因的鼠SP2/0细胞系,这一肿瘤细胞模型可作为研究bcr-abl基因疫苗的有效实验工具,为检验bcr-abl基因疫苗激发小鼠CTL应答的研究奠定物质基础。     

构建重组肿瘤基因疫苗对肿瘤进展及生存率影响的实验结局

目的：利用P815肿瘤动物模型观察IL-12对肿瘤动物模型抗肿瘤作用的效应。方法：将小鼠肥大细胞瘤P815特异抗原基因P1A克隆到真核表达质粒pCI—neo中；用P815细胞对DBA／2小鼠右腹侧皮下注射，构建P815小鼠肿瘤模型；以重组基因疫苗单独或与鼠IL-12真核表达质粒一起肌肉注射，观察肿瘤的消长、特异细胞毒T淋巴细胞激活和抗体的生成情况。结果：重组基因疫苗在体外有很好的表达，注射后细胞毒性T淋巴细胞(CTL)的杀伤效率为40％，IL-12共注射的CTL杀伤效率达到60％。免疫后，30％小鼠的肿瘤出现消退；同IL-12共注射则有50％的小鼠的肿瘤出现消退。两种情况下都不能检测到任何特异抗体的产生。结论：长期存在的IL-12可以持续刺激机体细胞免疫，使肿瘤的生存环境持续恶化，从而达到治疗肿瘤的目的。     

构建重组肿瘤基因疫苗对肿瘤进展及生存率影响的实验结局

目的 利用 P815肿瘤动物模型观察 IL- 12对肿瘤动物模型抗肿瘤作用的效应. 方法 将小鼠肥大细胞瘤 P815特异抗原基因 P1A克隆到真核表达质粒 pCI- neo中;用 P815细胞对 DBA/2小鼠右腹侧皮下注射,构建 P815小鼠肿瘤模型;以重组基因疫苗单独或与鼠 IL- 12真核表达质粒一起肌肉注射,观察肿瘤的消长、特异细胞毒 T淋巴细胞激活和抗体的生成情况. 结果 重组基因疫苗在体外有很好的表达,注射后细胞毒性 T淋巴细胞(CTL)的杀伤效率为 40%, IL- 12共注射的 CTL杀伤效率达到 60%.免疫后, 30%小鼠的肿瘤出现消退;同 IL- 12共注射则有 50%的小鼠的肿瘤出现消退.两种情况下都不能检测到任何特异抗体的产生. 结论 长期存在的 IL- 12可以持续刺激机体细胞免疫,使肿瘤的生存环境持续恶化,从而达到治疗肿瘤的目的.     

bcr-abl基因疫苗对小鼠SP2/0/bcr-abl移植瘤的影响

为了研究bcr—abl融合基因疫苗对小鼠SP2／0／bcr—abl移植瘤的影响，采用pVbcr—abl、pVbcr—abl／mIL7两种质粒分别免疫BALB／c小鼠，然后用SP2／0／bcr—abl细胞攻击免疫小鼠，观察疫苗对SP2／0／bcr—abl移植瘤生长的影响，检验其是否具有免疫保护作用。结果表明：用基因疫苗免疫的两个实验组与两个对照组（空白对照组和空载体对照组）相比，在移植肿瘤形成时间、肿瘤表面破溃时间、肿瘤体积、荷瘤生存期等指标上均存在明显差异。pVbcr—abl／mIL7免疫小鼠组的荷瘤生存时间比pVbcr—abl免疫组相对延长。常规病理学分析发现，对照组小鼠的移植瘤组织比较致密，瘤细胞体积较大，形状不规则，而两个免疫组的肿瘤组织较为疏松，肿瘤细胞体积相对较小，并有大量炎性细胞浸润。两个对照组小鼠的肝脏组织内发现有大量肿瘤转移灶，而两个免疫组小鼠则未发现。结论：接受bcr—abl基因疫苗免疫的小鼠被诱导产生较强的特异性免疫保护力，对SP2／0／bcr—abl移植瘤的体内生长有一定抑制能力。     

CD4-CD8- T cell receptor alpha beta T cells: generation of an in vitro major histocompatibility complex class I specific cytotoxic T lymphocyte response and allogeneic tumor rejection

The generation of an in vitro major histocompatibility complex class I specific response of CD4-CD8- T cell receptor (TCR) alpha beta cytotoxic T lymphocytes (CTL) and their allogeneic tumor rejection were investigated. Inocula of BALBRL male 1 were rejected in C57BL/6 (B6) mice treated with minimum essential medium (MEM) (control), anti-L3T4 (CD4) monoclonal antibody (mAb) or anti-Lyt-2.2 (CD8) mAb and CTL against the tumor were generated in vitro. No rejection and no induction of CTL were observed in B6 mice treated with anti-L3T4 (CD4) plus anti-Lyt-2.2 (CD8) mAb. CTL with the classical Thy-1+ CD3+CD4-CD8+ TCR alpha beta phenotype were generated in mixed lymphocyte tumor cell culture (MLTC) spleen cells from B6 mice treated with MEM (control) or anti-L3T4 (CD4) mAb, whereas CTL with an unusual Thy-1+CD3+CD4-CD8- TCR alpha beta phenotype were generated in MLTC spleen cells from anti-Lyt-2.2 (CD8) mAb-treated B6 mice. Both types of CTL were reactive with both H-2Kd and Dd (Ld) class I antigen. These findings suggest that when CD4+ cells were blocked by anti-L3T4 (CD4) mAb, CD8+ CTL mediated rejection, and when CD8+ cells were blocked by anti-Lyt-2.2 (CD8) mAb, CD4+ cells were capable of mediating rejection, although less efficiently than CD8+ cells, by inducing CD4-CD8- TCR alpha beta CTL. The finding that adoptive transfer of CD4 and CD8-depleted MLTC spleen cells, obtained from anti-Lyt-2.2 (CD8) mAb-treated B6 mice that had rejected BALBRL male 1, resulted in rejection of BALBRL male 1 inoculated into B6 nu/nu mice confirmed the above notion. CTL clones with the CD4-CD8- TCR alpha beta phenotype specific for Ld were established.     

Immature dendritic cells acquire CD8(+) cytotoxic T lymphocyte priming capacity upon activation by T helper cell-independent or -dependent stimuli

The well defined, immature murine dendritic cell (DC) line D1 was used to study the role of DC maturation in CTL induction in vitro and in vivo. Maturation of D1 cells, characterized by markedly increased expression of MHC and costimulatory molecules, was induced by incubation with lipopolysaccharide, agonistic CD40 antibody, or specific CD4(+) T helper (Th) cells. Activated, but not immature, D1 cells efficiently primed alloreactive T cell responses in vitro. Similarly, priming of CTL immunity in vivo in CD4-depleted mice was only observed if these mice were immunized with activated D1 cells. This study provides formal evidence that activation of DCs, induced by Th-independent as well as Th-dependent stimuli, is essential for efficient induction of CTL responses.     

人溶菌酶基因免疫抗体的制备及其初步应用

目的制备人溶菌酶(hLYZ)基因免疫抗体。方法用多聚乙酰亚胺包裹重组质粒pcDNA3LYZ,经肌肉注射途径免疫BALB/c小鼠,以间接ELISA检测免疫血清中hLYZ抗体的效价,所得抗体用Western-blotting法检测转基因小鼠乳汁中重组hLYZ的表达情况。结果2次免疫后,小鼠体内产生了hLYZ特异性抗体,效价达1∶800,用此抗体为第一抗体在转基因小鼠乳汁中检测到分子量与正常hLYZ相同的重组hLYZ。结论用基因免疫方法在小鼠体内制备了可用于检测的hLYZ抗体。     

Gene therapy with CX3CL1/Fractalkine induces antitumor immunity to regress effectively mouse hepatocellular carcinoma

CX3CL1/Fractalkine(FK), a chemokine existing in both secreted and membrane anchored form, was reported to induce suppressive activities in tumor models. Here, we demonstrate for the first time the antitumor effects of FK in murine hepatocellular carcinoma (HCC) by constructing a FK eukaryotic expression vector (pIRES-FK) and transferring it into such tumor cells. Tumor rejection experiments were performed by injecting FK gene-modified murine HCC cell line (MM45T.Li) into immunocompetent mice, which significantly inhibited tumorigenicity or growth of MM45T.Li-FK cells. Immunohistochemistry examination and fluorescence-activated cell sorting analyses revealed both CD4+ and CD8+ T cells infiltration within the tumor together with a marked increase of these cells in the peripheral blood. Splenic lymphocyte from mice treated with MM45T.Li-FK were effective in the induction of tumor-specific cytotoxic T cells. We also observed an increased production of IL-2 and IFN-gamma in MM45T.Li-FK tumor tissue. Our results suggest that transfer of the FK gene into tumor cells could elicit a specific antitumor immunity capable of inhibiting tumor growth which lead to increased survival of tumor-bearing hosts. FK should be considered as a chemokine suitable for cancer immunoprevention or gene therapy.     

Protective effect of a protein-bound polysaccharide, PSK, on CLP-induced sepsis in mice transplanted orthotopically with colon tumor

We investigated the effects of a protein-bound polysaccharide, PSK, on the resistance of tumor-bearing mice against sepsis induced by cecal ligation and puncture (CLP). (a) In BALB/c mice that had received intracecal transplantation of colon 26 (C26) tumor, CLP with a 21-gauge needle significantly shortened the survival time, compared with that of non-tumor-bearing mice. Oral administration of PSK to such mice resulted in a significant prolongation of the survival time and increase of the survival rates. The effects were dependent on the timing of PSK administration and the dose. (b) CLP significantly increased the IL-10 level in serum, the IL-10 gene expression by spleen cells, the number of IL-10-producing CD4-positive T cells, and the productivity of IL-10 by spleen of tumor-bearing mice compared with that of non-tumor-bearing mice. PSK administration to such mice suppressed the increase. Further, PSK prevented the reduction of gene expression of IFN-gamma and the number of IFN-gamma-producing CD4-positive T cells and IFN-gamma productivity by spleen cells of tumor-bearing CLP-treated mice. (c) Treatment with anti-IFN-gamma monoclonal antibody before CLP significantly reduced the effects of PSK. These findings suggest that the protective effect of PSK on the CLP-induced sepsis in mice transplanted orthotopically with C26 tumor is possibly mediated by suppression of IL-10 and promotion of IFN-gamma.