NK Cell Cytotoxicity Against Cryptococcus neoformans in Persons with Advanced HIV and Cryptococcal Meningitis

项目总结/摘要 新型隐球菌是一种机会性真菌病原体， 在免疫功能低下的个体中，例如在HIV感染者中，隐球菌病。一种生活- 隐球菌病的威胁性表现是隐球菌性脑膜炎（CM）;一种中枢神经系统感染 急性脑膜炎是HIV感染者脑膜炎的最常见原因。次 撒哈拉非洲承担着全球CM疾病负担和死亡率的大部分。因为免疫的宿主 反应是至关重要的清除感染和解决症状，一个坚实的了解主机 隐球菌感染状态下的免疫应答对于降低发病率和死亡率至关重要。 自然杀伤（NK）细胞是一种先天性淋巴免疫细胞，在CM中研究不足。NK细胞 具有抗原非依赖性细胞毒性能力，使其成为靶向细胞内和细胞外的理想选择。 细胞外病原体NK细胞的这一关键特征可能使其成为免疫系统中的一个重要方面。 回应C。neoformans，这是一种细胞内和细胞外的病原体。标准抗真菌药 治疗靶向病原体，但死亡率仍然发生，包括在具有无菌CSF培养物的人中。我 初步数据显示，低浓度的CSF中的NK细胞细胞毒性相关的可溶性分子 与CM患者急性14天死亡率的风险增加相关。因此，提高NK 细胞毒活性可能是降低隐球菌死亡率的创新治疗途径。 此外，鉴定与NK细胞功能受损有关的基因和途径， 调节以改善细胞毒性可能是未来治疗的目标。 我的中心假设是NK细胞有助于真菌清除C。新形式，但这是一个 NK细胞耗竭、细胞因子产生受损、抑制性受体增加和 由于潜在的HIV感染导致的活化受体表达的降低破坏了它们的细胞毒性能力。 为了检验中心假设，我提出以下目的：目的1旨在比较NK细胞天然 HIV感染CM死亡者的细胞毒性和抗体依赖性细胞介导的细胞毒性 在诊断后14天内和生存>14天的患者。目标2旨在确定患有CM的人是否 死亡14天内有高水平的差异表达基因参与耗尽和抑制 细胞毒性途径相比，谁生存CM的人。总的来说，这些发现将提供 首次定量NK细胞对C.临床分离株的细胞毒性。新生儿和鉴定 与急性CM死亡率相关的差异表达基因。这些信息将为我们提供具体的 参与耗竭、细胞因子产生和细胞毒性的基因，这些基因可以在细胞中调节。 宿主靶向免疫治疗的未来

PROJECT SUMMARY / ABSTRACT Cryptococcus neoformans is an opportunistic fungal pathogen that causes localized and disseminated disease, cryptococcosis, in immunocompromised individuals, such as in people living with HIV. A life- threatening manifestation of cryptococcosis is cryptococcal meningitis (CM); a central nervous system infection with acute inflammation of the meninges and the most common cause of meningitis in those with HIV. Sub- Saharan Africa carries the majority of the global CM disease burden and mortality. Because the host immune response is crucial to clearance of the infection and resolution of symptoms, a solid understanding of the host immune response in the state of cryptococcal infection is essential in order to reduce morbidity and mortality. Natural killer (NK) cells are an innate lymphoid immune cell that has been understudied in CM. NK cells have antigen independent cytotoxic ability that render them ideal for targeting both intracellular and extracellular pathogens. This key feature of NK cells could make them an important aspect in the immune response to C. neoformans, which is both an intracellular and extracellular pathogen. Standard antifungal therapy targets the pathogen, yet mortality still occurs, including among persons with sterile CSF cultures. My preliminary data has shown that low CSF concentrations of NK cell cytotoxicity associated soluble molecules are associated with increased risk of acute 14-day mortality in persons with CM. Therefore, improving NK cytotoxic activity may be an innovative therapeutic pathway toward reducing cryptococcal mortality. Additionally, the identification of genes and pathways implicated in impaired NK cell function that could be modulated to improve cytotoxicity could be targets for future therapeutics. My central hypothesis is that NK cells contribute to fungal clearance of C. neoformans, but that a combination of NK cell exhaustion, impaired cytokine production, increased inhibitory receptors, and decreased activating receptor expression due to the underlying HIV infection disrupts their cytotoxic abilities. To test the central hypothesis, I am proposing the following Aims: Aim 1 seeks to compare NK cell natural cytotoxicity and antibody-dependent cell mediated cytotoxicity between HIV-infected persons with CM who die within 14-days of diagnosis and those who survive >14 day. Aim 2 seeks to determine if persons with CM who die within 14-days have high levels of differentially expressed genes involved in exhaustion and inhibition of cytotoxicity pathways when compared to persons who survive CM. Collectively, these findings will provide the first quantification of NK cell cytotoxicity against clinical isolates of C. neoformans and the identification of differentially expressed genes associated with acute CM mortality. This information will provide us with specific genes that are involved in exhaustion, cytokine production, and cytotoxicity that could be modulated in the future with host targeted immunotherapy.