Immune Response to Cryptococcal Infections

对隐球菌感染的免疫反应

• 批准号: 9264958
• 负责人: Stuart Michael Levitz
• 金额: $ 49.25万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-05-01 至 2020-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9264958
• 关键词: Acquired Immunodeficiency Syndrome; Address; Adjuvant; Adoptive Transfer; Antibodies; Antibody Response; Antigens; Attenuated; Attenuated Vaccines; Biological Assay; CD4 Positive T Lymphocytes; CD8-Positive T-Lymphocytes; CD8B1 gene; Carbohydrates; Carrier Proteins; Cell Wall; Cell physiology; Cells; Combined Vaccines; Conjugate Vaccines; Cryptococcal Meningitis; Cryptococcus; Cryptococcus gattii; Cryptococcus neoformans; Cryptococcus neoformans infection; Development; Diphtheria Toxoid; Disease; Encapsulated; Endemic Diseases; Escherichia coli; Formulation; Funding; Glucans; Goals; Graft Rejection; HIV; Health Priorities; Hematologic Neoplasms; Immune; Immune response; Immune system; Immunocompetent; Immunocompromised Host; Incidence; Individual; Infection; Left; Link; Mass Spectrum Analysis; Mediating; Modeling; Mus; Neurologic; Pacific Northwest; Patients; Peripheral Blood Mononuclear Cell; Persons; Pharmaceutical Preparations; Phenotype; Polysaccharides; Populations at Risk; Preclinical Testing; Proteins; Proteome; Recombinants; Risk Factors; Role; Site; Survivors; T cell response; T-Lymphocyte; TNFRSF10A gene; Testing; Transgenic Mice; United States National Institutes of Health; Vaccinated; Vaccination; Vaccine Antigen; Vaccines; Yeasts; alkalinity; arm; beta-Glucans; design; disability; fungus; global health; immunoreactivity; immunosuppressed; killings; mortality; novel vaccines; particle; polyglucosan; preclinical development; prevent; public health relevance; response; vaccine candidate; vaccine development; vaccine evaluation; vaccine response; vaccine-induced immunity

 DESCRIPTION (provided by applicant): Cryptococcal meningitis, due to the encapsulated yeast C. neoformans (Cn), is estimated to kill over 600,000 people annually. Most victims have compromised CD4+ T cell function. A closely related species, C. gattii (Cg), causes endemic disease in persons who generally have mild or no immunocompromise. Development of a vaccine to protect against cryptococcosis is a global health priority. The goal of this project is the preclinical development of candidate vaccines to protect at risk populations from cryptococcosis. We hypothesize such a vaccine will have a subunit formulation and consist of cryptococcal antigens (Ags) delivered with adjuvant(s) that stimulate strong and durable T cell and antibody (Ab) responses. Aim 1 is to synthesize candidate cryptococcal vaccine Ags and test the Ags for immunoreactivity. In preliminary studies, we have obtained 100% protection against lethal cryptococcosis by vaccinating mice with glucan particles (GPs) containing alkaline extracts derived from Cn. The proteome of the protective extract has been defined; however, it is not known which Ags are responsible for protection. In Aim 1A, Ags in the extracts will be recombinantly expressed and tested for their capacity to stimulate ex vivo CD4-biased T cell responses using cells from vaccinated mice and cryptococcosis patients. It is recognized that vaccine-mediated protection can involve arm(s) of the immune system that do not have a predominant role in natural infection. In Aim 1B, GXM, the major capsular component of Cn, will be conjugated to diphtheria toxoid. This is predicted to convert the glycan into a potent immunogen capable of eliciting protective Ab responses. Aim 2 is to formulate candidate cryptococcal vaccines and perform preclinical testing. By the end of Aim 1, we anticipate we will have identified ~10 Cn Ags that stimulate T cell responses and we will have made conjugate vaccines that stimulate Ab responses against GXM. In Aim 2A, we will determine which of these candidate Ags stimulate protective responses in models of cryptococcosis. In Aim 2B, we will optimize Ag combinations and vaccine formulations, including testing GPs and CpG alone and in combination. The durability of protection will be explored. In Aim 2C, we will explore the immune mechanisms of vaccine-induced protection. In Aim 2D, recognizing that AIDS is the major risk factor for cryptococcosis, the effect of CD4-depletion on CD8+ and Ab vaccine responses will be defined. Finally, in Aim 2E, we will test whether vaccine-mediated protection can be achieved against Cg infections. We anticipate that at the end of the funding period, we will have created candidate vaccines capable of eliciting robust and durable Ag-specific Ab and Th1-biased responses that protect mice against challenge with Cn and Cg. The studies address an NIH-identified need for development of cryptococcal vaccines and should establish proofs of principle applicable to other vaccine-preventable diseases, particularly those for which T cell defenses are paramount.

 描述（由申请人提供）：隐球菌性脑膜炎是由新型隐球菌 (Cn) 引起的，估计每年导致超过 600,000 人死亡。大多数受害者的 CD4+ T 细胞功能受损。一种密切相关的物种，格特隐球菌（Cg），会在通常患有轻度或无免疫功能低下的人中引起地方性疾病。开发预防隐球菌病的疫苗是全球健康的首要任务。该项目的目标是候选疫苗的临床前开发，以保护高危人群免受隐球菌病的侵害。我们假设这种疫苗将采用亚单位配方，由隐球菌抗原 (Ag) 和佐剂组成，可刺激强烈且持久的 T 细胞和抗体 (Ab) 反应。目标 1 是合成候选隐球菌疫苗 Ags 并测试 Ags 的免疫反应性。在初步研究中，我们通过给小鼠接种含有 Cn 碱性提取物的葡聚糖颗粒 (GP) 疫苗，获得了 100% 的针对致命性隐球菌病的保护。保护性提取物的蛋白质组已被定义；然而，尚不清楚哪些Ag负责保护。在目标 1A 中，提取物中的 Ag 将被重组表达，并使用来自接种疫苗的小鼠和隐球菌病患者的细胞来测试其刺激离体 CD4 偏向 T 细胞反应的能力。人们认识到，疫苗介导的保护可能涉及在自然感染中不起主导作用的免疫系统臂。在目标 1B 中，GXM（Cn 的主要荚膜成分）将与白喉类毒素结合。预计这会将聚糖转化为能够引发保护性抗体反应的有效免疫原。目标 2 是制定候选隐球菌疫苗并进行临床前测试。到目标 1 结束时，我们预计将鉴定出约 10 个能刺激 T 细胞反应的 Cn Ag，并且我们将制造出能刺激针对 GXM 的 Ab 反应的结合疫苗。在目标 2A 中，我们将确定这些候选抗原中哪些会刺激隐球菌病模型中的保护性反应。在目标 2B 中，我们将优化 Ag 组合和疫苗配方，包括单独和组合测试 GP 和 CpG。将探讨保护的持久性。在目标 2C 中，我们将探讨疫苗诱导保护的免疫机制。在 Aim 2D 中，认识到艾滋病是隐球菌病的主要危险因素，将定义 CD4 耗竭对 CD8+ 和 Ab 疫苗反应的影响。最后，在目标 2E 中，我们将测试是否可以实现针对 Cg 感染的疫苗介导的保护。我们预计，在资助期结束时，我们将创造出能够引发强大而持久的 Ag 特异性 Ab 和 Th1 偏向反应的候选疫苗，从而保护小鼠免受 Cn 和 Cg 的攻击。这些研究解决了 NIH 确定的开发隐球菌疫苗的需求，并应建立适用于其他疫苗可预防疾病的原理证明，特别是那些 T 细胞防御至关重要的疾病。