GENETICALLY MODIFIED DENDRITIC CELLS FOR INDUCTION OF CANCER IMMUNITY

癌症免疫学的一个中心问题是设计肿瘤抗原如何 可以刺激和激活免疫反应。 大多数肿瘤 抗原是自身抗原，并且可能诱导免疫耐受，除非 它们被适当地呈递给免疫系统。 几乎在每一 系统测试，树突状细胞是最有效的抗原呈递细胞 它们可以刺激和激活辅助和细胞毒性T细胞， 前体T细胞是静止的，以低频率存在，这种情况 这适用于肿瘤反应性淋巴细胞 这个项目的目标是 利用树突状细胞作为抗原呈递者的能力， 改造它们来呈递肿瘤抗原。 因此， 工作基于以下三个前提。 (I)树突细胞 有效的抗原呈递细胞，而肿瘤细胞不是。 (ii)基因 转移可用于抗原的最佳选择和呈递。 (iii)基因转移可以在体内产生持续的抗原表达。 在 为了测试该模型，我们将使用定义的肿瘤分化 黑色素瘤模型中的酪氨酸家族抗原和突变型p53 癌蛋白在肉瘤模型中的作用。 首先，在小鼠中进行基因转移， 人类树突状细胞“已经在初步实验中实现” 将通过测试不同类型的结构进行优化， 转导、稳定表达和抗原呈递的条件 体外和体内。 树突状细胞表达的免疫应答 然后将在体外和体内研究肿瘤抗原。 策略 需要打破对肿瘤分化抗原的耐受性。 我们有 发现打破耐受性的一种方法是免疫接种， 同源分化抗原，以诱导对自身抗原的免疫 由肿瘤表达。 将使用小鼠模型来测量 在何种程度上同源肿瘤抗原， 通过同基因小鼠树突状细胞，可以打破免疫耐受， 诱导肿瘤排斥。 这些研究将开发临床前原理 以及使用遗传修饰的树突状细胞 针对确定的癌抗原的免疫。

A central problem in cancer immunology is to devise how tumor antigens could be made to stimulate and activate immune responses. Most tumor antigens are self-antigens, and likely induce immune tolerance unless they are appropriately presented to the immune system. In almost every system tested, dendritic cells are the most potent antigen-presenting cells they can stimulate and activate helper and cytotoxic T cells even when precursor T cells are quiescent and present at low frequencies, a situation that applies to tumor-reactive lymphocytes. The goal of this project is to exploit the power of dendritic cells as antigen presenters by engineering them to present tumor antigens. Thus, the rationale for this work is based on the three following premises. (I) Dendritic cells are potent antigen-presenting cells, while tumor cells are not. (ii) Gene transfer can be used for optimal selection and presentations of antigens. (iii) Gene transfer can produce sustained antigen expression in vivo. In order to test this model, we will use a defined tumor differentiation antigen of the tyrosine family in a melanoma model and a mutant p53 oncoprotein in a sarcoma model. First, gene transfer in mouse and human dendritic cells "already achieved in preliminary experiments" will be optimized by testing different types of constructs with respect to conditions of transduction, stable expression, and antigen presentation in vitro and in vivo. The immune response to dendritic cells expressing tumor antigens will then be studied in vitro and in vivo. Strategies are needed to break tolerance to tumor differentiation antigens. We have found that one approach to breaking tolerance is immunization with homologous differentiation antigen to induce immunity to the self antigen expressed by tumors. Mouse models will be used in order to measure to what extent a homologous tumor antigen, expressed in and presented by syngeneic mouse dendritic cells, can break immune tolerance and induce tumor rejection. These studies will develop preclinical rationale and strategies for using genetically modified dendritic cells for immunization to defined cancer antigens.