Preclinical studies of a Cryptococcus vaccine for AIDS patients

项目总结/摘要 据估计，15%的艾滋病相关死亡是由于隐球菌病。我们通过基因工程 新型隐球菌菌株，命名为cda 1 - 2 - 3 - 4，它缺乏三个编码几丁质的基因， 脱乙酰酶（CDA）。值得注意的是，给予单次肺内接种活的或热灭活的小鼠， cda 1 → 2 → 3 → 3 → 4能产生长期的保护作用，抵抗其它致命的C.即使CD 4 + T细胞 在真菌攻击时细胞被耗尽。壳聚糖生产中的其他隐球菌菌株突变体，或 在不同培养基中生长的野生型菌株也具有保护性，尽管有些菌株引起有害的促炎性反应， 应答这三个具体目标的重点是发展一个机械的理解， 免疫和疫苗保护决定因素。长期目标是开发一种隐球菌 疫苗，以保护高危人群，特别是艾滋病毒感染者。目的1是确定 CD 4 + T细胞充足的小鼠中cda 1 β 2 β 3 β疫苗介导的保护作用。我们假设， cda 1 → 2 → 3 → 4导致Th 1偏斜抗原特异性CD 4 + T细胞的产生和扩增， 通过产生募集和/或激活抗真菌效应细胞的细胞因子来协调疫苗免疫。我们 将剖析接种疫苗和感染后的细胞和细胞因子反应，询问 巨噬细胞和树突状细胞偏斜，并定义保护所需的细胞和细胞因子。目标二是 确定当CD 4 + T细胞被激活时，负责疫苗介导保护的效应机制。 在挑战阶段耗尽。我们的初步数据表明，小鼠需要CD 4 + T细胞， 接种cda 1 - 2 - 3疫苗以产生保护性免疫力，但当小鼠接受 C.致命挑战新人类这种可塑性表明了一种策略，艾滋病毒感染者可以通过这种策略 当他们的CD 4 + T细胞升高时接种疫苗，当他们的CD 4 + T细胞升高时仍然可以保护他们免受隐球菌病的侵害。 细胞计数下降。我们将进一步定义对CD 4 + T细胞的需求，并确定效应机制 弥补CD 4 + T细胞的损失。目的3：确定C.新形动物， 驱动完全不同的宿主反应，集中在高度炎症反应与保护性反应。 这一目标是我们发现全细胞隐球菌疫苗可以在免疫球蛋白中表现出显著的变化之后的后续。 导致的肺部炎症我们将描述保护性和炎症性的性质 反应，并确定驱动这些反应的真菌配体。我们预计， 资金期间，我们将有一个主机和真菌因素负责机械的理解 CD 4 + T细胞充足和CD 4 + T细胞缺陷小鼠通过cda 1/2/3/4疫苗株的保护。该提案 解决了隐球菌疫苗开发的一个主要全球卫生需求， 原则上适用于其他艾滋病相关的机会性感染和粘膜疫苗。

Project Summary/Abstract An estimated 15% of AIDS-related deaths are due to cryptococcosis. We have genetically engineered a Cryptococcus neoformans strain, designated cda1∆2∆3∆, that it is deficient in three genes encoding for chitin deacetylases (CDA). Remarkably, mice given a single intrapulmonary vaccination with live or heat-killed cda1∆2∆3∆ develop long-term protection against an otherwise lethal C. neoformans challenge, even if CD4+ T cells are depleted at the time of fungal challenge. Other cryptococcal strains mutant in chitosan production, or wild type strains grown in different media, also are protective, although some elicit deleterious proinflammatory responses. The three specific aims are focused on developing a mechanistic understanding of the immunological and vaccine determinants of protection. The long-term objective is to develop a cryptococcal vaccine to protect at risk individuals, particularly persons living with HIV. Aim 1 is to determine correlates of cda1∆2∆3∆ vaccine-mediated protection in CD4+ T cell-sufficient mice. We hypothesize that vaccination with cda1∆2∆3∆ results in the generation and expansion of Th1-skewed antigen-specific CD4+ T cells which orchestrate vaccine immunity by producing cytokines which recruit and/or activate antifungal effector cells. We will dissect the cellular and cytokine response following vaccination and infection, interrogate the role of macrophage and dendritic cells skewing, and define the cells and cytokines required for protection. Aim 2 is to determine the effector mechanisms responsible for vaccine-mediated protection when CD4+ T cells are depleted during the challenge phase. Our preliminary data demonstrate that CD4+ T cells are required for mice vaccinated with cda1∆2∆3∆ to develop protective immunity, but then become dispensable when mice receive a lethal challenge of C. neoformans. This plasticity suggests a strategy whereby persons with HIV can be vaccinated when their CD4+ T cells are elevated and still be protected from cryptococcosis when their CD4+ T cells counts fall. We will further define the requirement for CD4+ T cells and identify the effector mechanisms that compensate for the loss of CD4+ T cells. Aim 3 is to determine the components of C. neoformans which drive disparate host responses, focusing on the highly inflammatory response versus the protective response. This aim follows up our discovery that whole cell cryptococcal vaccines can exhibit marked variations in the amount of lung inflammation they induce. We will characterize the nature of the protective and inflammatory response and determine the fungal ligands that drive these responses. We anticipate that at the end of the funding period, we will have a mechanistic understanding of the host and fungal factors responsible for protection of CD4+ T cell-sufficient and -deficient mice by the cda1∆2∆3∆ vaccine strain. The proposal addresses a major global health need for the development of cryptococcal vaccines and could establish proofs of principle applicable to other AIDS-related opportunistic infections and mucosal vaccines.