LSUHSC COBRE:PROJ 2: OVERCOMING TUMOR TOLER THROUGH IN VIVO GEN* DENDRITIC CELLS

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。通过体内生成的树突状细胞克服肿瘤耐受性：有效免疫治疗的主要障碍之一是现有的T细胞对肿瘤抗原的耐受性或能量。近年来，大量的研究工作都集中在利用体外操纵树突状细胞（DC）的树突状细胞疫苗上。虽然这些传统的DC疫苗方法在增强抗原呈递和T细胞活化方面显示出有希望的结果，但它们未能提供足够和持续的免疫激活来克服肿瘤耐受性，部分原因是有限数量的体外操纵抗原呈递DC到达适当的淋巴细胞室。在这里，我们开发了一种新的策略，将肿瘤抗原基因特异性地靶向大量体内源性dc，以刺激大量和持续的免疫激活。这个概念已经用外源抗原如血凝素进行了测试，但是在肿瘤微环境中用肿瘤抗原测试这个概念是很困难的。我们的初步数据表明，使用特定载体可以控制体内呈递抗原的数量和类型。因此，我们的中心假设是“在体内生成的，肿瘤抗原基因修饰的dc将提供持续的刺激并诱导能够消除肿瘤的强大抗肿瘤免疫”。提出的工作是高度创新的，并将在使用天然肿瘤抗原HER2/neu的两个特定目标中验证这一假设。首先，她将测试体内衍生的表达HER2/neu的树突状细胞可以刺激强烈的免疫激活来克服耐受性的假设，使用特定载体，允许在特定细胞类型中控制和调节抗原表达。其次，用这个系统，她将测试这种强激活将导致抗原特异性效应T细胞充分募集到肿瘤部位以消除肿瘤的假设。本项目不仅解决了肿瘤诱导能量的机制，这是癌症免疫学的一个重要研究领域，而且还探索了一个新的概念，即抗原剂量、DC激活状态和体内持久性在克服肿瘤诱导耐受中的作用。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Overcoming Tumor Tolerance through in vivo generated dendritic cells: One of the major hurdles for effective immunotherapy treatment is the existing T cell tolerance or anergy to tumor antigens. Recently, tremendous efforts have been focused on dendritic cells (DC) based vaccine using ex vivo manipulated DCs. While these conventional DC vaccine approaches showed promising outcomes in enhancing antigen presentation and T cell activation, they failed to provide sufficient and sustained immune activation to overcome tumor tolerance, in part due to the limited number of ex vivo manipulated antigen presenting DCs reaching appropriate lymphoid compartment. Here we developed a new strategy to specifically target tumor antigen gene to in vivo derived DCs in great number to stimulate substantial and sustained immune activation. This concept has been tested using foreign antigens such as hemagglutinin, however testing this concept with tumor antigens in a tumor microenvironment has been difficult. Our preliminary data suggest that using specific vectors may control the amount and type of antigen being presented in vivo. Thus, our central hypothesis is that "in vivo generated, tumor antigen gene modified DCs will provide sustained stimulation and induce a strong anti-tumor immunity capable of tumor elimination". The work proposed is highly innovative and will test this hypothesis in two specific aims using a native tumor antigen HER2/neu. First, she will test the hypothesis that in vivo derived HER2/neu expressing dendritic cells can stimulate a strong immune activation to overcome tolerance, using specific vectors that allow controlled and regulated antigen expression in specific cell types. Second, with this system she will test the hypothesis that this strong activation will result in sufficient recruitment of antigen specific effector T cells to tumor sites for tumor elimination. This project not only addresses the mechanisms of tumor induced anergy, a major field of research in cancer immunology, but also explores a novel concept, i.e. the roles of antigen dose, DC activation status and persistence in vivo in overcoming tumor induced tolerance.