Natural killer cell and T-cell crosstalk in CMV infection

摘要 人巨细胞病毒(HCMV)是引起先天性病毒感染的最常见原因。 实体器官和造血细胞致病致死的重要原因 移植。了解免疫系统对巨细胞病毒的反应对这项工作至关重要。 以实现高效根除感染。这项提议旨在确定新的关系 在巨细胞病毒感染过程中NK细胞和T细胞之间的关系，中心假设是一个强大的T细胞 细胞对巨细胞病毒感染的反应可以消除NK记忆表型的出现； 反过来，巨细胞病毒激活的NK细胞可以调节T细胞反应的大小。 利用独特的完全自体的体外人巨细胞病毒感染系统，调节关系 可以对NK细胞和T细胞之间的相互作用进行研究和鉴定。初步研究表明 新发现NK细胞与感染巨细胞病毒的树突状细胞直接相互作用 诱导NK细胞表面表达PD-L1，直接抑制抗体介导的T细胞 扩散。检测PDL1 NK细胞对人巨细胞病毒抗原特异性T细胞、T细胞的影响 利用人工抗原提呈细胞刺激对人巨细胞病毒感染的反应 用CMVpp65多肽冲击。巨细胞病毒激活的PDL1 NK细胞与巨细胞病毒载体共孵育 致敏的T细胞将允许阐明一种淋巴细胞对另一种淋巴细胞的调节作用。 此外，来自活体小鼠模型的初步数据概括了 人体研究表明，PDL1 NK细胞的数量在 巨细胞病毒感染C57BL/6小鼠的实验研究使用新的基因小鼠系统，在体内的影响 PDL1 NK细胞对MCMV特异性T细胞的应答和病毒清除效率将 下定决心。这些小鼠模型将允许NK细胞反应强度的相关性 与CMV特异性T细胞反应的关系，也将提供对这种关系是如何 控制住了。自然杀伤细胞与T细胞关系的体外和体外研究进展 活体研究将应用于适应性NKG2C NK的扩增和维持的研究 健康人捐献者和干细胞后巨细胞病毒再激活患者的细胞 移植。一组造血细胞移植队列的血液样本的可用性 巨细胞病毒再激活为患者提供了检测NK和T细胞的独特机会 巨细胞病毒感染背景曲目。这些研究将描述新的机制，将 扩展现有的关于适应性免疫系统和先天免疫系统平衡的知识 病毒感染，并将提供进一步的洞察力，可以有针对性地预防 重新激活和慢性病毒感染。

ABSTRACT Human cytomegalovirus (HCMV) is the most common cause of congenital viral infection and an important cause of morbidity and mortality following solid organ and hematopoietic cell transplantation. Understanding how the immune system responds to HCMV is vital to the efforts to achieve efficient eradication of infection. This proposal aims to identify novel relationships between NK cells and T cells during HCMV infection, with the central hypothesis that a strong T cell response to HCMV infection can abrogate the emergence of an NK memory phenotype; reciprocally, a HCMV-activated NK cell can regulate the magnitude of the T-cell response. Using a unique fully autologous in vitro HCMV infection system, regulatory relationships between NK cells and T cells can be investigated and identified. Preliminary studies have generated the novel finding that direct interaction of NK cells with HCMV-infected dendritic cells induces PD-L1 surface expression on NK cells, which directly inhibits antibody-mediated T cell proliferation. To determine the impact of PDL1+ NK cell on HCMV antigen specific T cells, T cell responses to HCMV infection will be stimulated by the use of an artificial antigen-presenting cell pulsed with CMVpp65 peptides. Co-incubation of CMV-activated PDL1+ NK cells and CMV- sensitized T cells will permit elucidation of regulatory effects of one lymphocyte on the other. Additionally, preliminary data from an in vivo murine model has recapitulated findings in the human studies, showing a significant increase in the number of PDL1+ NK cells following MCMV infection of C57BL/6 mice. Using genetically novel murine systems, the in vivo impact of PDL1+ NK cells on MCMV-specific T cell responses and the efficiency of viral clearance will be determined. These murine models will allow for correlation of strength of the NK cell response with CMV-specific T cell responses and will also provide insight to how this relationship is controlled. The understanding of NK and T cell relationships developed in the in vitro and in vivo studies will be applied to the study of expansion and maintenance of adaptive NKG2C+ NK cells in healthy human donors as well as in patients with CMV reactivation following stem cell transplantation. The availability of blood samples from a cohort of hematopoietic cell transplant patients with CMV reactivation provides the unique opportunity to examine the NK and T cell repertoire in the setting of CMV infection. These studies will describe novel mechanisms that will expand existing knowledge on the balance of the adaptive and innate immune systems during viral infection and will provide further insight to mechanisms that can be targeted to prevent reactivation and chronic viral infection.