热休克蛋白70融合肿瘤抗原基因的DNA疫苗研究进展

在抗肿瘤免疫治疗中,已经发展了多种形式的热休克蛋白70(HSP70)相关治疗性疫苗,这些疫苗主要包括蛋白疫苗、肽疫苗、细胞疫苗及DNA疫苗等,其中HSP70融合DNA疫苗凭借其自身的优势引起人们的关注。它不但可诱导高效、持久的抗肿瘤免疫应答,而且可以维持免疫记忆。本文就HSP70在肿瘤治疗性DNA疫苗中的作用和应用作一综述。     

DNA疫苗与抗肿瘤免疫

DNA疫苗是近年发展起来的新一代疫苗 ,能够诱导宿主体内细胞毒T细胞反应和抗体反应。大量实验研究证明 ,注射抗肿瘤DNA疫苗能获得肿瘤保护性免疫效应 ,在肿瘤免疫治疗中应用前景看好。本文对DNA疫苗抗肿瘤免疫的机制、影响因素及应用作一综述     

006 DNA疫苗与抗肿瘤免疫

DNA疫苗是近年发展起来的新一代疫苗,能够诱导宿主体内细胞毒T细胞反应和抗体反应.大量实验研究证明,注射抗肿瘤DNA疫苗能获得肿瘤保护性免疫效应,在肿瘤免疫治疗中应用前景看好.本文对DNA疫苗抗肿瘤免疫的机制、影响因素及应用作一综述.     

DNA疫苗与抗肿瘤免疫

DNA疫苗是近年发展起来的新一代疫苗，能够诱导宿主体内细胞毒T细胞反应和抗体反应。本量实验研究证明，注射抗肿瘤DNA疫苗能获得肿瘤保护性免疫效应，在肿瘤免疫治疗中应用前景看好。本文对DNA疫苗抗肿瘤免疫的机制，影响因素及应用作一综述。     

妇科恶性肿瘤的免疫治疗

肿瘤的免疫治疗是继传统的手术、放疗、化疗之后发展起来的第四种治疗方法。近年来随着分子生物学、免疫学及基因工程学的迅速发展 ,使人们能在分子水平认识肿瘤的发生、发展及机体的抗肿瘤免疫机制 ,从而研究出了肿瘤的免疫治疗。疫苗是最常用的一种主动免疫疗法 ,目前研究较多的是肽疫苗 ,树突状细胞 (Dendritic Cells,DC)疫苗 ,基因工程疫苗和抗独特型抗体疫苗。现综述如下 :1　肽疫苗T细胞不能认识完整的肿瘤抗原蛋白 ,它只能识别经加工并与主要组织相容复合体 (MHC)共同表达在细胞表面上的抗原肽 ,这些肽是代表抗原决定簇的小肽 ,…     

树突状细胞肿瘤疫苗的研究进展

在抗肿瘤免疫应答中,关键的一步是抗原呈递细胞将肿瘤抗原呈递给T淋巴细胞。树突状细胞是专职抗原呈递细胞,它能够有效的将肿瘤抗原呈递给T细胞,引发机体产生抗肿瘤的免疫应答。因此,利用树突状细胞制备肿瘤疫苗可望提供一种有效的肿瘤免疫治疗方法。目前,体外实验、动物实验和初期的临床实验都已经证明了树突状细胞肿瘤疫苗的抗肿瘤作用。本文主要介绍树突状细胞的生物学特征和树突状细胞肿瘤疫苗在肿瘤免疫治疗中的研究进展。     

GVAX肿瘤疫苗研究进展

肿瘤免疫治疗是通过调节机体的免疫功能从而达到杀灭肿瘤细胞的一种治疗手段,有望成为继手术、放疗、化疗之后第四种抗肿瘤治疗方法。根据机体抗肿瘤免疫效应机制的不同,肿瘤免疫治疗可分为主动免疫治疗和被动免疫治疗两大类。GVAX肿瘤疫苗是一种典型的肿瘤主动免疫治疗,近年来在肿瘤免疫治疗研究中已成为新的热点,并取得了不少进展。本文就GVAX瘤苗的原理,在实验动物模型及临床试验研究中的疗效、安全性、临床应用前景等内容作一综述。     

DNA疫苗的分子佐剂研究进展

DNA疫苗是一种能诱生机体产生高水平免疫应答的新型疫苗 ,近年来有关它的研究不断扩展和深入。由于它受到DNA疫苗以表达抗原蛋白的重组质粒DNA为免疫原的启发 ,为进一步优化DNA疫苗 ,人们开始研究一类新型的DNA疫苗分子佐剂 ,即可在体内表达各种免疫相关分子的重组质粒DNA和具免疫刺激效应的细菌源性CpGDNA。本文介绍了各种分子佐剂对DNA疫苗的调制效应及其在疫苗优化、免疫治疗和DNA疫苗作用机制探索中的意义 ,就影响分子佐剂对DNA疫苗调制的因素问题作了一些讨论。     

肿瘤疫苗的研究现状

肿瘤在体内的排斥/控制主要依赖于肿瘤抗原特异性T淋巴细胞.T淋巴细胞通过TCR与肿瘤细胞表面表达的HLA-抗原肽复合物的相互作用来识别其靶分子.与特异性HLA-抗原肽复合物有价值的相互作用诱导了淋巴细胞克隆的扩增以及一系列的免疫反应.目前,从理论上已经提出了以整个肿瘤细胞,或纯化的肿瘤抗原作为疫苗(包括整个蛋白质分子和抗原肽及纯化的DNA分子)来提高免疫系统对肿瘤的识别和排斥.本文从免疫系统对肿瘤细胞的识别、疫苗诱导的体内抗肿瘤免疫的假设机制、疫苗接种所诱导的抗肿瘤反应以及临床结果几个方面,对当前肿瘤疫苗的研究现状作一简要综述,并对肿瘤疫苗研究中尚待解决的问题作了简单的归纳.     

针对MUC1黏蛋白DC疫苗的研究进展

树突状细胞(DC)作为抗原递呈细胞在激活肿瘤特异性免疫中发挥重要作用,DC疫苗为肿瘤免疫治疗提供了一种有效手段.MUC1是一种高分子量糖蛋白,属于粘蛋白家族成员,在多种上皮性肿瘤中异常表达,是肿瘤免疫治疗的理想靶抗原.本文综述了MUC1的生物学特征、DC对MUC1的递呈和以MUC1为靶点DC疫苗的抗肿瘤效果.     

产肠毒素大肠杆菌混合载体疫苗的免疫原性评价

本研究在构建表达ETEC菌毛抗原CFA/I、CS6和CS3、融合肠毒素LTB/STm的混合活载体疫苗的基础上 ,以两株福氏志贺载体疫苗 ,同等剂量相混合进行免疫。通过口服免疫 ,该混合多价活疫苗能够诱导机体产生相应的抗ETEC特异的血清和黏膜抗原抗体反应 ,达到了与各单独疫苗株一致的免疫效果 ,同时保持了载体志贺菌自身的免疫原性。     

树突状细胞肿瘤疫苗的研究进展

树突状细胞(DC)是目前发现的功能最强大的专职抗原递呈细胞(APC),能激活静息T细胞并使其增殖,产生抗原特异性细胞毒性T淋巴细胞(CTL),从而发挥抗肿瘤免疫效应.近年来,人们在肿瘤疫苗的研究中,采用多种策略制备DC肿瘤疫苗,尝试通过改变机体免疫系统对肿瘤的免疫状态来加强机体的免疫功能,进而清除肿瘤细胞,而对正常组织几乎无伤害,因此有很好的临床应用前景.     

肿瘤微环境中负性调节树突状细胞功能的因素及治疗策略

在肿瘤免疫治疗中,树突状细胞(DCs)因拥有强大的抗原提呈功能而受到了极大的关注,但并非所有的DCs肿瘤疫苗都能够获得预期的效果.肿瘤微环境中及DCs自身存在的多种因素对DCs 抗原提呈功能的抑制是影响DCs肿瘤疫苗作用的一个重要原因.因此,认识并靶向性地降低或消除这些抑制性因素是增强Des肿瘤疫苗的一个重要研究方向.     

新型肿瘤疫苗研究现况及进展

肿瘤疫苗是肿瘤主动特异性免疫治疗(activespecificimmunotherapy)的核心.由于肿瘤细胞缺乏特异性抗原及必要的抗原呈递而使肿瘤疫苗制备非常困难.由于分子免疫学及基因工程技术的迅速发展,出现了转基因瘤苗、DC及B细胞瘤苗、核酸瘤苗、抗独特型瘤苗及HSP-多肽复合物瘤苗等新型高效瘤苗.本文就此作一综述,并介绍新的瘤苗制备和构建方法.     

Fusion of CpG-ODN-stimulating dendritic cells with Lewis lung cancer cells can enhance anti-tumor immune responses

Immunogenicity of tumor cells is generally weak. Therefore, dendritic cells (DCs) have been used to boost anti-tumor responses of DC-based vaccines. DC function is highly dependent on its subsets and the level of its maturation. Nowadays, DC/tumor cell fusion vaccines are already used in clinical trials, and there are numerous studies discussing the effects of cytidine-phosphate-guanosine-containing oligonucleotides (CpG-ODN) on various cell types including DC. CpG-ODN a powerful immuno-stimulant can drive DCs fully mature, thus improve the efficacy of vaccine therapy. There are two simple ways to help load tumor antigens onto DCs by direct contact with cells themselves: fusion or co-culture of DCs with whole tumor cells. In this study, we combined these two approaches to improve the efficacy of DC/tumor cell-based vaccine. Mature DCs are adept at presenting processed Ag to T cells with loss of its capacity to capture Ag, while immature DCs are on the contrary. Our results emphasize the necessity of considering the stage of DC maturation and corresponding choice of tumor antigen delivery when designing approaches for prophylaxis or therapy of tumors using DC-based immunization protocols. We used CpG-ODN-1826-stimulated mature DCs and non-CpG-ODN-stimulating DCs as sources of tumor antigen carriers to investigate the appropriate Ag-loading ways between fusion and co-culture. Our results displayed that DC/tumor vaccine using CpG-ODN-stimulating mature DCs fused, not co-cultured, with tumor cells can generate a consistent and highly effective anti-tumor immune responses in vivo.     

治疗性疫苗的研究进展

随着人们在免疫学及生物化学领域的研究中不断取得重大的突破,一种全新概念的疫苗--治疗性疫苗的研究迅速发展起来.治疗性疫苗通过改善和增强靶抗原的摄人、表达、处理、递呈,从根本上重新唤起机体对靶抗原的免疫应答能力,从而打破机体的免疫耐受、增强机体特异性免疫反应,能够对一些目前尚无有效治疗方法的慢性传染性疾病及肿瘤等起到治疗作用.目前治疗性疫苗在某些病毒性传染病、细菌性传染病、自身免疫病及肿瘤等方面都进行了大量研究,并取得了一定成就.     

Enhanced immunogenicity to food-and-mouth disease virus in mice vaccination with alphaviral replicon-based DNA vaccine expressing the capsid precursor polypeptide (P1)

Recently, alphavirus replicon-based DNA vaccines, also known as suicidal DNA vaccines, have emerged as an important strategy to enhance the potency of DNA vaccines. In this study, two different types of DNA vaccines encoding the capsid precursor polypeptide (P1) of foot-and-mouth disease virus (FMDV) were constructed and the immunogenicity were investigated and compared in mouse model. The first DNA vaccine, pcDP1, is a conventional plasmid DNA vaccine in which P1 was driven directly by a cytomegalovirus promoter. The second DNA vaccine, pSCAP1, is a Semliki Forest virus (SFV) replicon-based DNA vaccine encoding the same antigen. In vitro expression and characterization indicated that two vaccine vectors could correctly produce the P1 antigen. However, pSCAP1 could induce obvious apoptosis of the transfected cells. After immunization in BALB/c mice, the P1-specific ELISA antibodies, neutralizing antibodies, as well as lymphocyte proliferative responses induced by pSCAP1 were significantly higher than those obtained in mice immunized with pcDP1. Notably, mice immunized with the pSCAP1 had the determined ability of clearing virus in their sera after FMDV challenge. These results indicate that the SFV replicon-based DNA vaccine pSCAP1 are more effective than conventional DNA vaccine and it can be considered a promising approach for the development of a safety and efficacious vaccine against FMDV.     

Multiple copies of a tumor epitope in a recombinant hepatitis B surface antigen (HBsAg) vaccine enhance CTL responses, but not tumor protection

We propose the replacement of endogenous epitopes with foreign epitopes to exploit the highly immunogenic hepatitis B surface antigen (HBsAg) as a vaccine vector to elicit disease-protective cytotoxic T-lymphocyte (CTL) responses. Locations were defined within the HBsAg gene where replacements of DNA encoding HBsAg epitopes may be made to generate functional recombinant (r) HBsAg DNA vaccines. We demonstrate that rHBsAg DNA vaccines encoding multiple copies of a model tumor epitope from human papillomavirus (HPV) elicit enhanced CTL responses compared to rHBsAg DNA vaccines encoding a single copy. We show that rHBsAg DNA vaccines elicit a marked prophylactic and long-lived therapeutic protection against epitope expressing tumor, although protective efficacy was not improved by increasing the number of copies of the tumor epitope DNA. These results demonstrate the efficacy of HBsAg as a vector for the delivery of foreign CTL epitopes using the epitope replacement strategy, and have implications for rHBsAg vaccine design. The results also have implications for the derivation of a therapeutic vaccine for HPV-associated squamous carcinoma.     

Therapeutic vaccine for lymphoma

The unique antigenic determinants (Idiotype [Id]) of the immunoglobulin expressed on a given B-cell malignancy can serve as a tumor-specific antigen for active immunotherapy. Therapeutic vaccines targeting the tumor-specific idiotype have demonstrated promising results against lymphomas in phase I/II studies and are currently being evaluated in phase III randomized trials. Additional vaccine therapies being developed include those based on DNA, dendritic cells, gene-modified tumor cells. It is hoped that immunotherapeutic agents, used in tandem or in combination, may in the future allow effective treatment of lymphoid malignancies and delay or even replace the need for conventional cytotoxic therapies.     

Reengineering dendritic cell-based anti-cancer vaccines

Summary: Despite initial enthusiasm, dendritic cell (DC)-based anti-cancer vaccines have yet to live up to their promise as one of the best hopes for generating effective anti-tumor immunity. One of the principal reasons for the generally disappointing results achieved thus far could be that the full potential of DCs has not been effectively exploited. Here, we argue that dramatic improvements in vaccine efficacy will probably require a careful re-evaluation of current vaccine design. The formulation of new strategies must take into account the natural history of DCs, particularly their role in helping the immune system deal with infection. Equally critical is the emerging importance of soluble factors, notably interleukin-12, in modulating the quality of immune responses. Vaccines should also be designed to recruit helper T cells and antibody-producing B cells rather than simply cytotoxic T lymphocytes. Finally, the judicious selection of tumor, target antigen, and disease stage best suited for treatment should serve as the foundation of trial designs. Our discussion addresses a recent clinical vaccine trial to treat early breast cancer, where many elements of this new strategy were put into practice.