LOCAL MODULATION OF DENDRITIC CELLS FOR MECHANISTIC INSIGHT

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目及 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者的研究机构。 我们已经开发了一种简单的抗原特异性抗肿瘤免疫疗法，在严格的大鼠乳腺癌模型中靶向非突变的“自身”肿瘤相关抗原（TAA）neu，该模型使用了一种新型甲病毒衍生的复制子颗粒（VRP）载体，该载体具有对树突状细胞（DC）的向性，树突状细胞是最有效的免疫刺激性抗原呈递细胞。这种免疫疗法激发了显着的抗肿瘤免疫反应，包括治愈一部分（？20-40%）;在靶向单一、真正的“自身”TAA的可比较的抗肿瘤疫苗策略中很少报道（仅4次报道）的活性水平。尽管我们的治愈率不是100%，但是消除肿瘤的动物没有复发，并且显著地，在抗原特异性治疗的背景下生长的肿瘤具有TAA表达的下调。这种活性水平虽然有希望，但不是最佳的，这表明导致鉴定增强活性的方法的机制见解将加速这种有希望的抗肿瘤免疫疗法向临床竞技场的转化，并对癌症患者产生更大的影响。本研究的中心假设是：DC嗜性对于基于VRP的抗肿瘤免疫疗法的有效活性至关重要，并且受到增强免疫疗法活性的方法的影响。 以下具体目标将是检验这一假设的第一步： 具体目的：确定DC向性在基于VRP的抗肿瘤免疫治疗活性中的作用。 这一目标将解决的问题，是重要的了解这种VRP载体系统elevenly有效的抗肿瘤免疫反应的机制。我们将特别采用策略来增加用于VRP转导的DC的局部可用性，预测这将导致增强的抗肿瘤免疫。我们还将在VRP施用之前耗尽局部DC，预测免疫治疗活性将被废除。 1. 通过用GM-CSF或单核细胞/DC特异性趋化因子CXCL 14将未成熟DC募集到外周部位并用咪喹莫特耗尽未成熟DC来调节局部外周DC群体。 2. 检查局部DC调节对体内VRP转导效率和DC活化的影响。 3. 评估局部DC群体调节对基于VRP的免疫疗法的疗效的影响。 这些研究将提供初步数据，以支持扩展的特定目标和研究计划，以1）改善VRP免疫治疗，2）进一步探索VRP机制问题，3）提供数据以加快临床转化和临床研究。

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. We have developed a straightforward antigen-specific anti-tumor immunotherapy, targeting the non-mutated "self" tumor associated antigen (TAA), neu, in a stringent rat breast cancer model that uses a novel alphavirus-derived replicon particle (VRP) vector with tropism for dendritic cells (DCs), the most potent immunostimulatory antigen-presenting cell. This immunotherapy elicits significant anti-tumor immune responses including the ability to cure a proportion (?20-40%) of animals with pre-existing tumor; a level of activity rarely reported (only four reports) in comparable anti-tumor vaccine strategies targeting single, true "self" TAAs. Although our cure rate is not 100%, no animals eliminating their tumors relapsed and significantly, tumors that grew in the setting of antigen-specific therapy had down-regulation of TAA expression. This level of activity, although promising, is less than optimal suggesting that mechanistic insights leading to identification of methods to enhance activity would accelerate the translation of this promising anti-tumor immunotherapy into the clinical arena and result in greater impact for cancer patients. The Central Hypothesis of this study is: DC tropism is critical for the potent activity of VRP-based anti-tumor immunotherapies and is subject to methods to enhance immunotherapy activity. The following Specific Aim will be the initial step in testing this hypothesis: Specific Aim: Define the role of DC tropism in the activity of VRP-based anti-tumor immunotherapy. This aim will address questions that are important for understanding the mechanisms by which this VRP vector system elicits potent anti-tumor immune responses. We will specifically employ maneuvers to increase the local availability of DCs for VRP transduction with the prediction that this will result in enhanced anti-tumor immunity. We will also deplete local DCs prior to VRP administration with the prediction that immunotherapy activity will be abrogated. 1. Modulate local peripheral DC populations by recruiting immature DCs to peripheral sites with GM-CSF or the monocyte/DC-specific chemokine CXCL14 and depleting immature DCs with Imiquimod. 2. Examine the effect of local DC modulation on in vivo VRP transduction efficiency and DC activation. 3. Evaluate the effect of local DC population modulation on the efficacy of VRP-based immunotherapy. These studies will provide the preliminary data to support an expanded specific aim and research plan to 1) improve the VRP immunotherapy, 2) further explore VRP mechanistic questions, and 3) provide data to expedite clinical translation and clinical study.