GENETIC MODIFICATION OF HUMAN DENDRITIC CELLS FOR CANCER IMMUNITY

描述（由申请人提供）：我们对人类树突状细胞的理解的进展已经解决了许多关于先天性和适应性免疫的发生以及树突状细胞如何控制这些抗癌反应的重要未知因素。肿瘤抗原本身是弱免疫原，因为它们是自身抗原或改变自身的抗原。因此，克服对癌症自身抗原的耐受性的障碍虽然是可以实现的，但却相当高。树突状细胞可以通过呈递肿瘤抗原以及引发免疫反应的所有其他必需分子来绕过许多这些屏障。然而，还必须解决涉及吲哚胺2，3-双加氧酶（IDO）和调节淋巴细胞介导的抵消抑制机制。遗传策略在将肿瘤抗原偶联至树突状细胞方面提供了优势。可以表达多个表位，针对多种MHC等位基因进行定制。抗原呈递随时间持续，细胞因子和其他共刺激分子可以被操纵，并且免疫抑制机制可以被改变。我们将解决这些领域的一系列可测试的假设，使用人类朗格汉斯型树突状细胞，基因修饰的逆转录病毒或质粒载体表达黑色素瘤抗原和其他蛋白质的兴趣。我们将通过遗传改变朗格汉斯细胞来引入IL-12 p70，以刺激和利用自然杀伤（NK）细胞的佐剂特性。还将测试新方法的朗格汉斯细胞的持续活化和通过活化性Fc-γ RII、CD 32a的转导表达改善的调理肿瘤抗原的交叉呈递。这将与基于基因的IL-12 p70-Fc融合构建体组合进行测试，以评估增加的细胞因子佐剂性。遗传学方法，干扰抑制机制，涉及IDO和调节淋巴细胞介导的将进行研究。这些研究的结果应该导致通过单一的遗传优化的树突状细胞来改善、协调刺激针对癌症的先天性和适应性免疫。（与公共卫生的相关性/非专业总结：将使用黑色素瘤作为模型，测试和改进特化朗格汉斯型树突细胞的遗传改变，以提高对癌症的免疫力。这些方法应该在治疗初级治疗后的微小残留疾病中找到最大的应用。

DESCRIPTION (provided by applicant): Advances in our understanding of human dendritic cells have resolved many important unknowns about the onset of innate and adaptive immunity and how dendritic cells could control these responses against cancer. Tumor antigens are poor immunogens by themselves, because they are either self or altered-self antigens. Hence the bar to overcoming tolerance toward cancer-self antigens, while attainable, is quite high. Dendritic cells can circumvent many of these barriers by presenting tumor antigens in association with all the other requisite molecules that elicit immune reactivity. Countervailing suppressor mechanisms involving indoleamine 2,3-dioxygenase (IDO) and mediated by regulatory lymphocytes must also be addressed, however. Genetic strategies offer advantages in coupling tumor antigens to dendritic cells. Multiple epitopes can be expressed, tailored to a variety of MHC alleles. Antigen-presentation is sustained over time, cytokines and other costimulatory molecules can be manipulated, and immune suppressor mechanisms can be altered. We will address these areas in a series of testable hypotheses using human Langerhans-type dendritic cells, genetically modified by retroviral or plasmid vectors to express melanoma antigens and other proteins of interest. We will introduce IL-12p70 by genetic alteration of Langerhans cells to stimulate and harness the adjuvant properties of natural killer (NK) cells. Novel approaches will also be tested for the sustained activation of Langerhans cells and improved cross-presentation of opsonized tumor antigen through transduced expression of the activating Fc-gamma Rll, CD32a. This will be tested in combination with gene-based IL-12p70-Fc fusion constructs to assess increased cytokine adjuvanticity. Genetic methods that interfere with suppressor mechanisms involving IDO and mediated by regulatory lymphocytes will be studied. The results of these studies should lead to improved, coordinate stimulation of innate and adaptive immunity against cancer by a single, genetically optimized dendritic cell. (Relevance to public health/Lay summary: Genetic alterations of specialized Langerhans-type dendritic cells will be tested and improved to increase immunity against cancer, using melanoma as the model. These approaches should find their greatest application in treating minimal residual disease after primary therapy.)