Preclinical studies of a Cryptococcus vaccine for AIDS patients

针对艾滋病患者的隐球菌疫苗的临床前研究

• 批准号: 10259153
• 负责人: Stuart Michael Levitz
• 金额: $ 79.9万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-02-11 至 2026-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10259153
• 关键词: AIDS Vaccines; AIDS-Related Opportunistic Infections; Acquired Immunodeficiency Syndrome; Address; Antifungal Agents; Antigens; CD4 Positive T Lymphocytes; Cell Count; Cells; Cessation of life; Chitin deacetylase; Chitosan; Cryptococcosis; Cryptococcus; Cryptococcus neoformans; Data; Dendritic Cells; Development; Effector Cell; Exhibits; Funding; Future; Generations; Genes; Genetic Engineering; Goals; HIV; Human; Immune response; Immunity; Immunologics; Individual; Infection; Inflammatory Response; Ligands; Lung Inflammation; Mediating; Mus; Nature; Patients; Persons; Phase; Production; Risk; Role; T-Lymphocyte; Testing; Time; Vaccinated; Vaccination; Vaccine Design; Vaccines; Variant; cell type; cytokine; design; falls; global health; macrophage; mucosal vaccine; mutant; pre-clinical; pre-clinical research; preclinical study; recruit; research clinical testing; response; tool; vaccine development

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.

项目概要/摘要 据估计，15% 的艾滋病相关死亡是由隐球菌病引起的。我们通过基因工程改造了一种隐球菌病。 新型隐球菌菌株，命名为 cda1Δ2Δ3Δ，它缺乏编码几丁质的三个基因 值得注意的是，小鼠接受了一次活疫苗或热灭活疫苗的肺内接种。 cda1Δ2Δ3Δ 开发长期保护措施，抵御致命的新型隐球菌挑战，即使 CD4+ T 壳聚糖生产中的其他隐球菌菌株突变体时细胞被耗尽，或 在不同培养基中生长的野生型菌株也具有保护性，尽管有些菌株会引起有害的促炎症反应 这三个具体目标侧重于形成对问题的机械理解。 保护的免疫学和疫苗决定因素。长期目标是开发隐球菌。 目标 1 是确定高危人群（特别是艾滋病毒感染者）的相关性。 cda1Δ2Δ3Δ 疫苗介导的 CD4+ T 细胞充足小鼠的保护作用 cda1Δ2Δ3Δ 导致 Th1 偏向抗原特异性 CD4+ T 细胞的生成和扩增， 通过产生招募和/或激活抗真菌效应细胞的细胞因子来协调疫苗免疫。 将剖析疫苗接种和感染后的细胞和细胞因子反应，探讨 目标 2 是确定巨噬细胞和树突状细胞的分布，并确定保护所需的细胞和细胞因子。 确定当 CD4+ T 细胞受到影响时负责疫苗介导保护的效应机制 我们的初步数据表明，CD4+ T 细胞是小鼠所必需的。 接种 cda1Δ2Δ3Δ 可产生保护性免疫力，但当小鼠接受 新型隐球菌的致命挑战表明，艾滋病毒感染者可以采取一种策略。 当他们的 CD4+ T 细胞升高并且仍然免受隐球菌感染时，他们的 CD4+ T 细胞将成为孤儿 我们将进一步明确对 CD4+ T 细胞的需求并确定效应机制。 目的 3 是确定新型隐球菌的组成部分。 驱动不同的宿主反应，重点关注高度炎症反应与保护性反应。 这一目标是继我们发现全细胞隐球菌疫苗在 我们将描述它们引起的肺部炎症的数量。 反应并确定驱动这些反应的真菌配体。 资助期间，我们将对宿主和负责的真菌因素有一个机制上的了解 通过 cda1Δ2Δ3Δ 疫苗株保护 CD4+ T 细胞充足和缺乏的小鼠 该提案。 满足开发隐球菌疫苗的主要全球健康需求，并可以建立证据 适用于其他与艾滋病有关的机会性感染和粘膜疫苗。