Activation of pDCs in Murine Tumor Models

强大的获得性免疫依赖于病原体来源的强大先天免疫反应 分子，如Toll样受体(TLR)配体。目前的癌症疫苗通常会诱导肿瘤特异性 T细胞，但无肿瘤消退。这可能是因为肿瘤缺乏TLR配体，先天减少 肿瘤中的免疫激活，从而限制了启动、积聚、原位激活和抗肿瘤 肿瘤特异性T细胞的效应功能。浆细胞样树突状细胞(PDC)是一种天然细胞。 关键是协调先天免疫反应和获得性免疫反应的免疫系统。PDDC一直是 发现于人类肿瘤内，因此是TLR7治疗干预的潜在理想靶点 和TLR9激动剂，激活pDC。然而，目前尚不清楚肿瘤内的pDC是激活的还是 它们在体内是否对TLR激动剂刺激有反应，以及这种刺激的下游效应是什么 激活是为了先天和获得性抗肿瘤免疫。此外，人们对这种机制知之甚少。 PDC可通过其在体内激发先天和获得性抗肿瘤免疫。自免疫以来 反应是复杂的，只有通过活体研究才能完全理解。我们已经开发出一种 小鼠模型，使我们能够在体内研究pDC在肿瘤中的存在和功能。我们发现 在小鼠黑色素瘤中存在非激活的pDC。TLR激动剂激活的pDC可以激活 传统的MDCs，增强它们在体内启动肿瘤特异性T细胞的能力。此外，激活 PDCs在体内有效地激活NK细胞以诱导肿瘤破坏和额外肿瘤特异性的从头启动 CD8T细胞。在我们建立的gplOO特异性TCR转基因PMEL-1小鼠模型基础上 先前，我们还发现，在体内，用TLR激动剂激活pDC可以增强肿瘤 由疫苗诱导的gplOO特异性CD8 T细胞介导的退化。基于这些数据，我们假设 体内TLR激动剂对肿瘤内pDC的激活将导致MDCS和NK细胞的激活。 肿瘤导致诱导强大的先天和适应性抗肿瘤免疫反应。为了测试这一点 假设我们将在体内用TLR激动剂激活肿瘤内的pDC，并测试它们的激活能力 MDCS和NK细胞，并诱导肿瘤特异性T细胞的积聚和肿瘤的破坏，通过 以下是具体目标： 具体目的1.研究肿瘤内pDC与MDCs相互作用的能力。 具体目的2.评价肿瘤内pDC与NK细胞的相互作用。 具体目标3.确定TLR激动剂对肿瘤内PDC的激活是否增强T细胞介导的 抗肿瘤作用。 我们的目标是确定可以推广到改善癌症免疫治疗的原则。 病人。

Strong adaptive immunity depends on a strong innate immune response triggered by pathogen-derived molecules, such as Toll-Like Receptor (TLR) ligands. Current cancer vaccines typically induce tumor-specific T cells but no tumor regression. This may be because tumors are deficient in TLR ligands, reducing innate immune activation in tumors and thereby limiting the priming, accumulation, in situ activation and anti-tumor effector function of tumor-specific T cells. Plasmacytoid Dendritic Cells (pDCs) are cells of the innate immune system that critically orchestrate both innate and adaptive immune responses. pDCs have been found inside human tumors and are therefore potentially ideal targets for therapeutic intervention with TLR7 and TLR9 agonists which activate pDCs. However, it is unknown whether intratumoral pDCs are activated or whether they can respond to TLR agonist stimulation in vivo, and what the downstream effects of such activation are for innate and adaptive anti-tumor immunity. In addition, little is known about the mechanism through which pDCs could stimulate innate and adaptive anti-tumor immunity in vivo. Since immune responses are complex, they can only be fully understood through in vivo studies. We have developed a mouse model that allows us to study the presence and function of pDCs in tumors in vivo. We found that non-activated pDCs were present in murine melanoma. TLR agonist-activated pDCs could activate conventional mDCs, enhancing their capacity to prime tumor-specific T cells in vivo. Furthermore, activated pDCs potently activated NK cells in vivo to induce tumor destruction and de novo priming of additional tumorspecific CD8+ T cells. Building on the gplOO-specific TCR transgenic pmel-1 mouse model we have previously developed, we also found that in vivo activation of pDCs with TLR agonists enhanced tumor regression mediated by vaccine-induced, gplOO-specific CD8+ T cells. Based on these data we hypothesize that activation of intratumoral pDCs by TLR agonists in vivo will result in activation of mDCs and NK cells in the tumor leading to the induction of potent innate and adaptive anti-tumor immune responses. To test this hypothesis we will activate intratumoral pDCs in vivo with TLR agonists and test their ability to activate mDCs and NK cells and to induce the accumulation of tumor-specific T cells and tumor destruction, through the following Specific Aims: ¿ Specific Aim 1. Characterize the ability of intratumoral pDCs to interact with mDCs. ¿ Specific Aim 2. Evaluate the interactions between intratumoral pDCs and NK cells. ¿ Specific Aim 3. Determine whether intratumoral pDC activation by TLR agonists enhances T cellmediated anti-tumor function. Our goal is to identify principles which may be generalized towards improving immunotherapy of cancer patients.