基因枪介导的neu基因DNA疫苗抗肿瘤作用的实验研究

目的 探讨DNA疫苗pWRG-neu的皮内免疫,对高表达neu基因的小鼠移植瘤生长和转移的抑制作用。方法 向小鼠黑色素瘤B16F10细胞系转染pcDNA-neu,用有限稀释法筛选一株高表达neu基因的细胞株B16F10-neu。在基因枪介导下,向C57BL／6小鼠导入DNA疫苗pWRG-neu,通过观察免疫动物的生存期,评价DNA疫苗的抗肿瘤作用。分离免疫动物脾细胞,经自体淋巴细胞混合培养实验,分析DNA疫苗体内免疫后机体的CTL应答。结果 筛选到一株高表达neu基因的B16F10-neu细胞株,转基因过程和外源基因的表达没有改变细胞系的增殖特性。用基因枪轰击,进行DNA疫苗pWRG-neu皮内免疫,对小鼠黑色素瘤B16F10-neu进行预防、治疗和抗转移的实验研究,结果表明,DNA疫苗的免疫能够明显推迟移植瘤的生长,延长小鼠生存期,获得明显的抗肿瘤效果。DNA疫苗免疫后可诱导小鼠脾淋巴细胞CTL活性。结论 基因枪介导的DNA疫苗pWRG-neu经皮内免疫,能够有效的诱导机体的细胞免疫应答,预防和治疗小鼠移植瘤的发生,并有一定的预防肿瘤肺转移的作用。     

B7-1基因转染骨肉瘤细胞诱导抗骨肉瘤主动免疫的实验研究

目的:探讨B7-1基因转染骨肉瘤细胞能否诱导抗骨肉瘤主动免疫作用。方法:利用脂质体将B7-1真核表达载体pcDNA3-B7-1和空载体pcDNA3分别导入骨肉瘤细胞株LM8中,G418筛选出阳性克隆(分别命名为LM8/B7-1和LM8/pcDNA3),通过RT-PCR、Western blot和流式细胞仪检测B7-1基因与蛋白的表达;通过软琼脂克隆形成实验观察转基因细胞株LM8/B7-1的体外增殖能力;用LM8、LM8/B7-1和LM8/pcDNA3分别经腹腔免疫小鼠,得到腹腔浸润淋巴细胞和致敏脾细胞,MTT法检测其体外杀伤活力;将LM8、LM8/B7-1和LM8/pcDNA3细胞分别接种到C3H雄性小鼠前腋下,观察其致瘤能力;观察LM8/B7-1致敏的小鼠对骨肉瘤细胞LM8是否具有免疫保护作用。结果:B7-1基因在转基因细胞LM8/B7-1中能得到高表达;LM8/B7-1体外增殖能力与LM8和LM8/pcDNA3无明显差异(P>0.05);LM8/B7-1诱导的CTL的杀伤活力显著高于LM8和LM8/pcDNA3诱导的CTL对相同靶细胞的杀伤活力,LM8/B7-1诱导的CTL对LM8/B7-1的杀伤活力也明显高于对LM8和LM8/pcDNA3的杀伤活力(P<0.05);LM8/B7-1致瘤能力较LM8和LM8/pcDNA3细胞明显下降(P<0.01);LM8/B7-1致敏的小鼠对骨肉瘤细胞LM8具有免疫保护作用。结论:B7-1基因转染骨肉瘤细胞能诱导抗骨肉瘤主动免疫作用,为利用B7-1基因进行骨肉瘤免疫基因治疗提供了实验依据。     

SLC基因修饰对肿瘤细胞疫苗免疫效果的初步研究

目的：构建次级淋巴组织趋化因子（secondary lymphoid—tissue chemokine，SLC）基因修饰的趋化型恶性黑色素瘤疫苗，并初步研究其免疫效果。方法：SLC基因转染小鼠黑色素瘤细胞B16，并用适当条件的丝裂霉素处理，制备趋化型肿瘤细胞疫苗。在体外，利用趋化小室法检测趋化型疫苗培养上清对小鼠脾淋巴细胞的趋化活性。在体内，用趋化型疫苗免疫小鼠，检测脾淋巴细胞的CTL活性，并观察疫苗免疫对B16移植瘤生长的影响。结果：筛选获得了SLC基因转染的小鼠黑色素瘤B16细胞，以100μg／mL丝裂霉素处理1.5h，制备趋化型肿瘤细胞疫苗。趋化型疫苗在体外培养48h后，其培养上清对淋巴细胞具有明显的趋化活性。与野生型疫苗相比，用趋化型疫苗免疫后，小鼠脾淋巴细胞的CTL活性更强，小鼠免疫后再次接种B16细胞，肿瘤的生长受到更明显的抑制。结论：成功构建了SLC基因修饰的趋化型黑色素瘤疫苗，并在体内外初步检测到该疫苗对抗肿瘤免疫的影响和对移植瘤生长的抑制，该疫苗有可能被应用于恶性黑色素瘤的免疫治疗。     

表达白细胞介素-12质粒DNA抗小鼠肝癌皮下移植瘤的作用

目的 探讨瘤内注射mIL-12质粒DNA抗小鼠肝癌皮下移植瘤的作用。方法：构建真核表达质粒载体pDC511mIL-12，ELISA方法检测质粒载体在真核细胞中的表达，淋巴母细胞增殖法检测mIL-12的生物学活性；分别于小鼠肝癌H22皮下移植瘤内直接注射质粒DNA，观察各组小鼠存活时间、肿瘤体积变化及各组小鼠脾脏细胞毒T淋巴细胞(CTL)的活性：注射质粒DNA后1月进行瘤体组织病理学观察：结果：mIL-12基因治疗组与空载体对照组相比，肿瘤生长显著受抑制(F=4．10，P=0．03)，小鼠存活期显著延长(X^2=4．48，P=0．03)．并且小鼠脾细胞CTL杀伤活性增强。质粒DNA瘤内注射1月后，pDC511mIL-12组肿瘤病灶炎性细胞浸润明显，病灶内肿瘤细胞广泛坏死。结论：瘤内注射mIL-12表达质粒DNA可抑制小鼠肝癌皮下移植瘤生长，能提高机体抗肿瘤免疫应答。     

树突状细胞与肿瘤细胞融合后诱导T细胞介导的抗肿瘤效应

目的：研究树突状细胞（DC）与肿瘤细胞（SP2／0）融合作为肿瘤疫苗免疫小鼠后抑制肿瘤生长的作用及其机理。方法：BALB／C小鼠DC与SP2／0细胞体外融合,形成的杂交瘤分2次免疫接种同基因小鼠皮下,然后用SP2／0细胞攻击免疫的小鼠,观察肿瘤的生长情况及免疫小鼠脾细胞特异性CTL功能。结果：DC－SP2／0杂交瘤接种小鼠能产生明显的抗肿瘤效应,其拮抗SP2／0细胞攻击的能力明显强于用灭活的死SP2／0细胞与DC混合,和单用死SP2／0细胞免疫的小鼠及用生理盐水的对照组小鼠。DC－SP2／0杂交瘤免疫接种小鼠的脾细胞特异性CTL杀伤活性强于其它各组小鼠。结论：DC与肿瘤细胞融合后作为肿瘤疫苗接种可在体内产生明显的抗肿瘤免疫,其机理主要是特异性CTL的作用。     

异位hCGβ-CTP37基因疫苗的抗肿瘤作用

目的 :研究异位hCGβ CTP37基因免疫诱导的肿瘤特异性免疫应答及其抗肿瘤作用 ,为肿瘤的免疫生物治疗寻求新途径。方法 :分离获取异位hCGβ CTP37的编码基因 ,并将 4拷贝基因以头尾串联形式克隆于真核表达载体TR42 1构建重组质粒TR42 1 CTP37.4,以PCR、酶切和DNA序列测定进行鉴定 ;肌内注射法对BALB/c小鼠实施 3次基因免疫 (1 0 0 μg/ 1 0 0 μl) (每只小鼠 ) ,间隔 3周 ,并以空载质粒为对照。ELISA法检测免疫小鼠血清中特异性抗hCGβ IgG抗体 ;免疫小鼠脾细胞经特异性抗原hCGβ刺激后 ,用3H TdR掺入法和同位素释放法分别检测其特异性淋巴细胞增殖活性和CTL细胞毒活性 ;皮下接种SP2 / 0 hCGβ细胞攻击免疫小鼠 ,以成瘤率及实体瘤重量评估体内抗瘤效果。结果 :TR42 1 CTP37.4质粒免疫小鼠产生了较高水平的抗hCGβ IgG抗体 ,与空载质粒组有显著差异 ;hCGβ蛋白刺激TR42 1 CTP37.4质粒免疫小鼠脾细胞生产了高水平的特异性淋巴细胞增殖活性 ,且明显高于空载质粒免疫小鼠 ;特异抗原诱导的TR42 1 CTP37.4质粒免疫小鼠脾细胞对SP2 / 0 hCGβ细胞的CTL活性明显高于SP2 / 0 preS2 /S细胞 P <0 .0 1 ) ;空质粒免疫小鼠接种SP2 / 0 hCGβ细胞后成瘤率为 1 0 0 % ,瘤重达 3 .37g,而TR42 1 CTP37.4质粒免     

共表达基因疫苗MAGE-1/IL-18的抗肿瘤免疫治疗作用

目的观察已构建的共表达基因疫苗pcIL-18-MAGE诱导特异性免疫应答的能力和抗肿瘤免疫治疗作用。方法共表达疫苗肌注小鼠,间隔十天加强免疫一次,共免疫三次,以pcMAGE-1、 pcIL-18、pcDNA3和PBS为对照,检测小鼠脾细胞上清液IL-12和IFN-γ的浓度、脾细胞CTL杀伤活性及小鼠T细胞亚群情况;观察基因疫苗免疫MAGE (+)小鼠的成瘤时间和生存时间。结果pcIL-18-MAGE质粒免疫的小鼠,其脾细胞对SMMC-7721的杀伤率最高,与各对照组相比,差异有统计学意义;脾细胞CD3⁺、CD4⁺、CD8⁺ T细胞和上清液中细胞因子IL-12和IFN-γ均明显升高。共表达疫苗免疫MAGE (+)小鼠后,小鼠成瘤时间明显延迟,生存时间明显延长。结论共表达基因疫苗pcIL-18-MAGE在实验动物体内有显著的诱导特异性抗肿瘤免疫作用,且对肿瘤的生成有一定的抑制作用。     

肿瘤排斥抗原SART1

T细胞识别的鳞状细胞癌抗原(SART)是近年来从鳞状细胞癌中发现的肿瘤自身抗原,能特异性诱导HLA限制性细胞毒性T淋巴细胞(CTL)产生杀瘤作用.SART1基因表达抗原蛋白SART-1259和SART-1800.SART-1259蛋白表达于多种肿瘤细胞细胞质,而在睾丸组织之外的正常组织不表达.从该抗原中得到的某些肽段能特异性诱导HLA限制性CTL产生杀瘤作用.现综述近年来SART1基因研究概况.     

肿瘤排斥抗原SART1

T细胞识别的鳞状细胞癌抗原(SART)是近年来从鳞状细胞癌中发现的肿瘤自身抗原，能特异性诱导HLA限制性细胞毒性T淋巴细胞(CTL)产生杀瘤作用。SART1基因表达抗原蛋白SART-1259和SART-1800。SART-1259蛋白表达于多种肿瘤细胞细胞质，而在睾丸组织之外的正常组织不表达。从该抗原中得到的某些肽段能特异性诱导HLA限制性CTL产生杀瘤作用。现综述近年来SART1基因研究概况。     

基于SFV RNA复制子核酸疫苗pIRSFV-HN的构建及其体内外抑瘤作用

目的：构建基于塞姆利基森林病毒（Semliki forest virus，SFV）RNA复制子和新城疫病毒HN基因的核酸疫苗pIRSFV-HN，并探讨其体内外的抑瘤作用。方法：基于SFV RNA复制子和新城疫病毒HN基因构建核酸疫苗pIRSFV-HN，pIRSFV-HN转染人结肠癌细胞HCT-116，以Western blotting检测转染后HCT-116细胞HN的表达水平，以AO／EB双荧光染色检测肿瘤细胞的凋亡，以MTT法检测疫苗对HCT-116细胞增殖的抑制。构建C57BL／6小鼠右后肢皮下荷H22腹水瘤细胞模型，瘤体内注射pIRSFV-HN（共3次），检测该小鼠血清IL-2、IL-4、IL-10和IFN-γ水平和特异性CTL活性。结果：成功构建基于SFV RNA复制子和新城疫病毒HN基因的核酸疫苗pIRSFV-HN。结肠癌细胞HCT-116被疫苗转染后可有效表达HN蛋白，对照细胞则无表达；转染后HCT-116细胞出现凋亡的征象；该细胞的增殖受到明显抑制，最大抑制率达55．34％。移植瘤体内注射疫苗后，荷瘤小鼠血清IL-2、IFN-1水平显著升高（P〈0．05），其CTL活性也显著升高（P〈0．01）。结论：基于SFV RNA复制子和新城疫病毒HN基因的核酸疫苗pIRSFV-HN在体外可有效地抑制肿瘤细胞；在体内可促使免疫趋向Th1优势，提高其抑瘤免疫水平。     

Anti-Tumor Efficacy of Gene Vaccine Expressing PSMA

OBJECTIVE To observe anti-tumor effects of PVAX-PSMA gene vaccine.METHODS The PSMA gene was inserted into a mammalian expression vector, PVAX-1, to construct the DNA vaccine candidate, and was then used to vaccinate C57BL/6 mice. Animals vaccinated with PVAX-1 and NaCl were used as controls.Anti-PSMA antibody was detected in sera of the animals. The proliferation and cytotoxicity of the spleen cells were observed. The immunized mice were inoculated with RM-1 cells. The mice were inoculated with RM-1 cells, and then the mice were immunized. The anti-tumor efficacy of the gene vaccine was evaluated by the ratio of tumor formation, tumor volume, tumor mass before and after gene vaccination and evaluated by survival rate of the immunized mice.RESULTS High level of anti-PSMA antibody was induced in the PVAX-PSMA group. The splenocytes from PVAX-PSMA group were stimulated to produce strong proliferation responses and significant cytotoxic T-cells (CTL) activity. After the mice were immunized with PVAX-PSMA gene, tumor occurrence was decreased, and the growth velocity of tumor was markedly reduced, resulting in prolonged tumor-free time (P < 0.05).CONCLUSION PVAX-PSMA gene vaccine has significant antitumor effects and provides an experimental basis for primary prevention and immunotherapy of prostate cancer.     

Induction of antigen specific cellular immunity by vaccination with peptides from MN/CA IX in renal cell carcinoma

We investigated the induction of the specific immunity for renal cell carcinomas (RCC) using MN/CA IX, a tumor-associated antigen frequently expressed in RCC. We have generated 9-mer peptide derived from MN/CA IX and examined the antigenicity as a vaccine to induce specific immunity for RCC. To use mouse syngeneic system, we transfected human MN/CA9 cDNA into RenCa and BALB-3T3 cells originally from BALB/c mouse, and established MN/CA IX expressing mouse cell lines, i.e., MN-RenCa and MN-3T3. The immunization of BALB/c mouse with MN-RenCa cells resulted in the induction of cytotoxic T lymphocytes (CTL) against MN/CA IX expressing cells and the CTL clone was established from bulked CTL. This CTL clone specifically lyzed MN-3T3 cells, but not parental cells. To identify the targeted epitope binding to H-2Kd antigen, three 9-mer peptides (A, B, C-peptide) of human MN/CA IX compatible with the H-2Kd as well as HLA-A24 binding motif was synthesized. The cloned CTL targeted the B-peptide pulsed BALB-3T3 cells as well as MN-3T3 cells. Furthermore, spleen cells from BALB/c mouse immunized with B-peptide reacted against MN-RenCa cells. These results suggest that the peptides derived from MN/CA IX containing HLA-A24 binding motif may be useful as a potent tumor vaccine for the treatment of human RCC, and in mouse models.     

腺病毒介导的人GM-CSF基因转染瘤苗增强机体免疫功能的实验研究

目的 研究腺病毒介导的人ＧＭ－ＣＳＦ基因转染瘤苗体内抗肿瘤免疫作用极其机理。方法 应用ＧＭ－ＣＳＦ基因转染、的瘤苗对小鼠肝癌模型进行免疫基因治疗,观察该疗法对荷瘤小鼠脾细胞ＮＫ、ＬＡＫ、ＣＴＬ活性的影响、脾淋巴细胞围化反应的影响以及荷瘤习的生存期。结果 经ＧＭ－ＣＳＦ基因转染瘤苗治疗后,插细胞ＣＴＬ活性显著升高,而ＮＫ、ＬＡＫ细胞活性未见明显增强、脾淋巴细胞转化反应显著增强、生存期显著延长。结论     

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。     

Dendritic cells transduced with tumor-associated antigen gene elicit potent therapeutic antitumor immunity: comparison with immunodominant peptide-pulsed DCs

Several studies have shown that vaccine therapy using dendritic cells (DCs) pulsed with specific tumor antigen peptides can effectively induce antitumor immunity. Peptide-pulsed DC therapy is reported to be effective against melanoma, while it is still not sufficient to show the antitumor therapeutic effect against epithelial solid tumors such as gastrointestinal malignancies. Recently, it has been reported that vaccine therapy using DCs transduced with a surrogate tumor antigen gene can elicit a potent therapeutic antitumor immunity. In this study, we investigated the efficacy of vaccine therapy using DCs transduced with the natural tumor antigen in comparison with peptide-pulsed DCs. DCs derived from murine bone marrow were adenovirally transduced with murine endogenous tumor antigen gp70 gene, which is expressed in CT26 cells, or DCs were pulsed with the immunodominant peptide AH-1 derived from gp70. We compared these two cancer vaccines in terms of induction of antigen-specific cytotoxic T lymphocyte (CTL) responses, CD4+ T cell response against tumor cells, migratory capacity of DCs and therapeutic immunity in vivo. The cytotoxic activity of splenocytes against CT26 and Meth-A pulsed with AH-1 in mice immunized with gp70 gene-transduced DCs was higher than that with AH-1-pulsed DCs. CD4+ T cells induced from mice immunized with gp70 gene-transduced DCs produced higher levels of IFN-gamma by stimulation with CT26 than those from mice immunized with AH-1-pulsed DCs (p < 0.0001), and it was suggested that DCs transduced with tumor-associated antigen (TAA) gene induced tumor-specific CD4+ T cells, and those CD4+ T cells played a critical role in the priming phase of the CD8+ T cell response for the induction of CD8+ CTL. Furthermore, DCs adenovirally transduced with TAA gene showed an enhancement of expression of CC chemokine receptor 7 and improved the migratory capacity to draining lymph nodes. In subcutaneous models, the vaccination using gp70 gene-transduced DCs provided a remarkably higher therapeutic efficacy than that using AH-1-pulsed DCs. These results suggested that vaccine therapy using DCs adenovirally transduced with TAA gene can elicit potent antitumor immunity, and may be useful for clinical application.     

Two oral HBx vaccines delivered by live attenuated Salmonella: both eliciting effective anti-tumor immunity

Live attenuated bacteria have great potential for use in vaccine development due to several unique advantages, including stable antigen expression, effective antigen presentation, convenient and inexpensive delivery, and low cost of vaccine production. In this study, we expressed hepatitis B virus x gene (HBx) on mouse melanoma cells as the target antigen and constructed Salmonella-based HBx vaccines by two strategies, i.e., recombinant eukaryotic plasmid encoding HBx and a recombinant prokaryotic plasmid encoding Type III secretion system effector-HBx fusion protein. Both HBx constructs elicited significant levels of CTL reaction and IFN-gamma secreting T cells. When mice were challenged with melanoma cells expressing HBx, tumor growth rates in immunized animals were significantly slower than controls. Tumor sizes and tumor weight indices of immunized mice were also significantly lower than controls. We conclude that both strategies described in this study may lead to novel approaches of tumor vaccines.     

腺病毒介导IL-2基因转染的瘤苗体内抗肿瘤作用

目的 :探讨重组腺病毒介导的 IL- 2基因转染的瘤苗的体内抗肿瘤作用及其免疫学机制。方法 :应用腺病毒介导的鼠 IL- 2基因转染 CT2 6小鼠结肠癌细胞 ,灭活后用作瘤苗治疗荷瘤小鼠 ,观察皮下肿瘤生长及其存活期。采用乳酸脱氢酶释放法检测荷瘤小鼠脾细胞 CTL、L AK、NK细胞的杀伤活性。结果 :鼠 IL- 2基因转染瘤苗治疗能显著抑制荷瘤小鼠皮下肿瘤生长并明显延长其存活期 (P<0 .0 1)。体内免疫功能检测表明 ,鼠 IL- 2基因转染疫苗治疗组小鼠脾细胞 CTL 活性、L AK活性和 NK活性显著高于对照组 (P<0 .0 1)。结论 :腺病毒介导鼠 IL- 2基因转染的瘤苗体内具有较强的抗肿瘤效应 ,其机制可能是提高了荷瘤小鼠特异性和非特异性抗肿瘤免疫反应     

The boosting effect of co-transduction with cytokine genes on cancer vaccine therapy using genetically modified dendritic cells expressing tumor-associated antigen

The T-helper 1 (Th1) immune reaction is most important in dendritic cell (DC)-based immunotherapy. Interleukin 12 (IL-12) and granulocyte macrophage colony-stimulating factor (GM-CSF) play a pivotal role in inducing Th1 and cytotoxic T lymphocyte (CTL) responses. In this study, DCs expressing the natural tumor antigen gp70 of BALB/c-derived CT26 were adenovirally transduced with the IL-12 gene and/or GM-CSF gene, and it was examined whether vaccinations using these genetically engineered DCs can induce strong therapeutic antitumor immunity. Mice were immunized once by subcutaneous (s.c.) injection with genetically modified DCs. The cytotoxic activity of splenocytes against CT26 was assayed in a 51Cr-release assay 14 days after immunization. The therapeutic efficacy of the vaccination was examined in s.c. tumor models. The cytotoxic activity of CTLs against CT26 in mice immunized with DCs expressing gp70 (DC-AxCAgp70) was significantly augmented by co-transduction with the GM-CSF/IL-12 gene (p<0.0001) and remarkably reduced by the depletion of CD4+ or CD8+ cells (p<0.01). The cytotoxic activity against CT26 of the plain spleen cells in mice immunized with DC-AxCAgp70/GM-CSF/IL-12 was significantly higher than that in mice immunized with DC-AxCAgp70 (p<0.0001), and this activity decreased to almost 50% upon the depletion of NK cells. Vaccinations using DC-AxCAgp70/GM-CSF/IL-12 or DC-AxCAgp70/IL-12 could elicit potent therapeutic immunity in s.c. tumor models; tumor-free mice were observed in these vaccination groups. However, there was no significant difference between these two groups. A vaccination therapy using DCs co-transduced with the TAA gene and Th 1-type cytokine genes, especially the IL-12 gene, is ideal for immunotherapy in terms of the activation of DCs, NK cells, CD4+ T cells and CD8+ T cells, and may be useful in the clinical application of a cancer vaccine therapy.     

Genetically modified dendritic cells prime autoreactive T cells through a pathway independent of CD40L and interleukin 12: implications for cancer vaccines

Genetic immunization through ex vivo transduction of dendritic cells has been suggested as an effective approach to enhance antitumor immunity by activating both CD4+ and CD8+ T cells. Immunizing mice with dendritic cells transduced with an adenovirus expressing the human melanoma antigen glycoprotein 100 (DCAdhgp100) as a cancer vaccine, we demonstrated complete protective immunity and a potent CTL response against melanomas expressing murine glycoprotein 100 in a CD4+ cell-dependent manner. Surprisingly, however, effective tumor rejection was not the result of cooperation between CD4+ and CD8+ T cells. Protective immunity was completely lost when CD4+ cells were depleted immediately before tumor challenge, whereas it was unaffected by removal of CD8+ cells, establishing a principal role for CD4+ cells in the effector phase of tumor rejection. Neither protective immunity nor CTL generation in this model required interleukin 12, in spite of high levels of IFN-gamma secretion by tumor-reactive T cells. Most notably, the DCAdhgp100 vaccine could elicit protective antitumor CD4+ cells in the absence of CD40 ligand, although it does not bypass the need for CD40-mediated signals to generate melanoma-reactive CTLs. Thus, in contrast to the current thinking that the optimal cancer vaccine should include determinants for both CD4+ and CD8+ cells, the potency of the DCAdhgp100 vaccine appears to be a result of its ability to directly prime autoreactive CD4+ cells through a process that does not require interleukin 12 and CD40 signals.     

Induction of effective antitumor immune responses in a mouse bladder tumor model by using DNA of an alpha antigen from mycobacteria

One of the main objectives of cancer immunotherapy is the activation and increase in number of antitumor effector cells. Recently, genetically modified tumor cell vaccines have been proposed for elicitation of antitumor effector cells. Native alpha antigen (alpha Ag) (also known as MPT59 and antigen 85B) of mycobacteria, which cross-reacts among mycobacteria species, may play an important biological role in host-pathogen interaction because it elicits various helper T-cell type 1 immune responses. To assess the induction of antitumor immune responses by alpha Ag, mouse tumor cell lines transfected with cDNA of alpha Ag from Mycobacterium kansasii were established, and the possibility of producing a tumor cell vaccine for induction of antitumor effects was explored. Transfection of tumor cell lines with an alpha Ag gene lead to primary tumor rejection and the establishment of protective immunity to nontransfected original tumor cell lines in Mycobacterium bovis bacillus Calmette-Gurin (BCG)-primed and unprimed mice. Mice immunized with tumor cell lines transfected with the alpha Ag gene showed delayed-type hypersensitivity responses in vivo and proliferative responses together with induction of interferon-gamma of spleen cells against nontransfected wild-type tumor cell lines in in vitro experiments. Moreover, immunization of mice with alpha Ag-expressing tumor cells elicited tumor-specific and cytotoxic T lymphocyte (CTL) epitope peptide-specific CD8+ CTLs. The results of this study provided evidence of the potential usefulness of alpha Ag in tumor cell vaccines.