GENETIC MODIFICATION OF HUMAN DENDRITIC CELLS FOR CANCER IMMUNITY

描述(申请人提供)：我们对人类树突状细胞的了解的进步已经解决了许多关于先天免疫和获得性免疫的开始以及树突状细胞如何控制这些抗癌反应的重要未知数。肿瘤抗原本身就是弱免疫原，因为它们要么是自身抗原，要么是改变的自身抗原。因此，克服对癌症自身抗原的耐受性的门槛虽然是可以达到的，但也是相当高的。树突状细胞可以通过递呈肿瘤抗原和所有其他诱导免疫反应的必需分子来绕过许多这些障碍。然而，涉及吲哚胺2，3-双加氧酶(IDO)并由调节性淋巴细胞介导的反补贴抑制机制也必须解决。基因策略在将肿瘤抗原与树突状细胞偶联方面提供了优势。可以表达多个表位，以适应不同的MHC等位基因。随着时间的推移，抗原呈递是持续的，细胞因子和其他共刺激分子可以被操纵，免疫抑制机制可以被改变。我们将使用人类朗格汉斯型树突状细胞，通过逆转录病毒或质粒载体进行基因修饰，表达黑色素瘤抗原和其他感兴趣的蛋白质，在一系列可测试的假设中解决这些问题。我们将通过郎格汉斯细胞的基因改变引入IL-12p70，以刺激和利用自然杀伤(NK)细胞的佐剂特性。新的方法也将被测试以持续激活朗格汉斯细胞，并通过转导表达激活的Fc-Gamma RLL，CD32a来改善调理的肿瘤抗原的交叉呈递。这将与基于基因的IL-12p70-Fc融合构建物结合进行测试，以评估细胞因子佐剂增加的情况。将研究干扰涉及IDO的抑制机制并由调节性淋巴细胞介导的遗传方法。这些研究的结果应该会导致单一的、经过基因优化的树突状细胞改善、协调地刺激先天免疫和获得性免疫以对抗癌症。(与公共卫生相关/Lay摘要：将以黑色素瘤为模型，测试和改进专门的朗格汉斯类型树突状细胞的基因改变，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病方面得到最大的应用。)

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.)