Regulatory Immune Cell Networks in Cancer

项目摘要 肿瘤抗原的表达激发了适应性免疫应答，在有利的情况下， 癌症患者的肿瘤排斥反应。然而，恶性生长的几个生物学特征更多 经常导致肿瘤特异性免疫耐受的发展。这种耐受性是诱导的， 通过多种免疫调节因子的复杂相互作用维持。调节性T细胞（Treg）， 骨髓来源的抑制细胞以及肿瘤浸润性巨噬细胞和骨髓树突细胞是 这些调控网络中最重要的细胞成分之一。很明显，当地 肿瘤微环境中Treg和髓样抗原呈递细胞（APC）之间的串扰是至关重要的 因为它们对抗肿瘤效应细胞的免疫抑制功能，最显著的是CD 8+细胞毒性T细胞， 淋巴细胞（CTL）。间接证据表明，Treg和骨髓APC之间的串扰，以及 CTL的抑制通过直接的细胞-细胞接触来实现， 可溶性因子和膜蛋白在抗原依赖性相互作用的背景下。然而，物理 肿瘤环境中T细胞-APC相互作用的性质、动力学和化学计量学尚未研究。在 为这个项目的初步工作，我们已经开发了一种多光子活体显微镜方法来研究 肿瘤相关APC和T细胞受体（TCR）的动态行为和细胞间信号交换 在麻醉小鼠的完整皮下肿瘤中的转基因肿瘤抗原特异性Treg和CTL。这 成像方法以亚细胞分辨率产生相互作用的T细胞和APC的3D延时电影， 将用于实现以下三个具体目标：1.为了描述肿瘤的局部影响- 浸润性骨髓APC和Treg对肿瘤中CTL积累和功能的影响; 2.）为了测试Treg介导的 CTL的抑制本身表现为TCR信号转导的损伤;和3.）探讨 在肿瘤环境中骨髓APC与CTL和Treg的细胞相互作用。拟议的实验 将产生一个全面的，以机制为导向的调查之间的局部相互作用免疫调节 髓系和淋巴系的细胞。这些信息可能会导致改善临床策略， 免疫调节，不仅用于肿瘤治疗，而且用于治疗感染性、炎性和 自身免疫性疾病

Project Summary The expression of tumor antigens elicits adaptive immune responses, which in favorable situations can lead to tumor rejection in cancer patients. However, several biological characteristics of malignant growths more frequently lead to the development of tumor-specific immunological tolerance. This tolerance is induced and maintained by the complex interplay of a multitude of immunoregulatory factors. T regulatory cells (Treg), myeloid-derived suppressor cells, as well as tumor-infiltrating macrophages and myeloid dendritic cells are among the most prominent cellular constituents of these regulatory networks. It is becoming apparent that local crosstalk between Treg and myeloid antigen-presenting cells (APC) in the tumor microenvironment is critical for their immunosuppressive function on anti-tumor effector cells, most prominently CD8+ cytotoxic T lymphocytes (CTL). Indirect evidence suggests that the crosstalk between Treg and myeloid APC, as well as the suppression of CTL is conferred by direct cell-cell contacts that allows for information exchange through soluble factors and membrane proteins in the context of antigen-dependent interactions. However, the physical nature, the kinetics, and stoichiometry of T cell-APC interactions in the tumor environment are unexplored. In preliminary work for this project, we have developed a multiphoton intravital microscopy approach to study the dynamic behavior and intercellular signal exchange of tumor-associated APC and T cell receptor (TCR) transgenic tumor-antigen-specific Treg and CTL in intact subcutaneous tumors of anesthetized mice. This imaging approach produces 3D time-lapse movies of interacting T cells and APC at subcellular resolution and will be used to address the following three specific aims: 1.) To characterize the local impact of tumor- infiltrating myeloid APC and Treg on CTL accumulation and function in tumors; 2.) To test if Treg-mediated suppression of CTL manifests itself in an impairment of TCR signal transduction; and 3.) To investigate the cellular interactions of myeloid APC with CTL and Treg in the tumor environment. The proposed experiments will generate a comprehensive, mechanism-oriented survey of the local interplay between immunoregulatory cells of the myeloid and the lymphoid lineage. This information may lead to improved strategies for clinical immunomodulation, not only for tumor therapy, but also for the treatment of infectious, inflammatory and autoimmune diseases.