Immune Response to Cryptococcal Infections

对隐球菌感染的免疫反应

• 批准号: 8963535
• 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/8963535
• 关键词: Acquired Immunodeficiency Syndrome; Address; Adjuvant; Adoptive Transfer; Antibodies; Antibody Response; Antigens; Attenuated; Attenuated Vaccines; Biological Assay; CD4 Positive T Lymphocytes; CD8B1 gene; Carbohydrates; Carrier Proteins; Cell Wall; Cell physiology; Cells; Combined Vaccines; Conjugate Vaccines; Cryptococcal Meningitis; Cryptococcus; Cryptococcus gattii; Cryptococcus neoformans infection; Development; Diphtheria Toxoid; Disease; Drug Formulations; Encapsulated; Endemic Diseases; Escherichia coli; Funding; Glucans; Goals; Graft Rejection; HIV; Health Priorities; Hematologic Neoplasms; Immune; Immune response; Immune system; Immunocompetent; Immunocompromised Host; Incidence; 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; arm; design; disability; fungus; global health; immunoreactivity; immunosuppressed; killings; mortality; novel vaccines; particle; polyglucosan; pre-clinical; 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(申请人提供)：隐球菌性脑膜炎，由于被包裹的酵母新生芽孢杆菌(CN)，估计每年导致超过60万人死亡。大多数患者的CD4+T细胞功能受损。一种密切相关的物种，C.gattii(CG)，会在通常有轻微或没有免疫损害的人中引起地方性疾病。开发预防隐球菌病的疫苗是全球卫生优先事项。该项目的目标是在临床前开发候选疫苗，以保护高危人群免受隐球菌病的侵袭。我们假设这样的疫苗将有一个亚单位配方，并由隐球菌抗原(AG)和佐剂(S)组成，这些佐剂能刺激强大而持久的T细胞和抗体(Ab)反应。目的1合成候选隐球菌疫苗AGS并检测其免疫反应性。在初步研究中，我们已经通过给小鼠接种含有从CN提取的碱性提取物的葡聚糖颗粒(GP)来获得100%对致命性隐球菌病的保护。保护性提取物的蛋白质组已经被定义；然而，还不知道哪些AGS负责保护。在目标1A中，将重组表达提取物中的AGS，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它们刺激体外以CD4为基础的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要作用的免疫系统的手臂(S)。在AIM 1B中，CN的主要囊膜成分GXM将与白喉类毒素结合。据预测，这将把多糖转化为一种有效的免疫原，能够引起保护性抗体反应。目标2是研制候选的隐球菌疫苗并进行临床前测试。到目标1结束时，我们预计我们将鉴定出约10个刺激T细胞反应的CN抗原，我们将研制出刺激抗GXM抗体反应的结合疫苗。在目标2A中，我们将确定这些候选AGs中的哪一个在隐球菌病模型中刺激保护性反应。在目标2B中，我们将优化Ag组合和疫苗配方，包括单独和联合测试GPs和CpG。将探索保护的持久性。在目标2C中，我们将探索疫苗诱导保护的免疫机制。在目标2D中，认识到艾滋病是隐球菌病的主要危险因素，将定义CD4耗尽对CD8+和抗体疫苗应答的影响。最后，在目标2e中，我们将测试疫苗介导的保护措施是否可以实现对CG感染的保护。我们预计，在资助期结束时，我们将创造出能够激发强大而持久的Ag特异性抗体和Th1偏向反应的候选疫苗，以保护小鼠免受CN和CG的挑战。这些研究解决了美国国立卫生研究院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据，特别是那些T细胞防御至关重要的疾病。