Protective Immune Responses to Blastomyces Dermatitidis

对皮炎芽生菌的保护性免疫反应

• 批准号: 6510718
• 负责人: BRUCE Steven KLEIN
• 金额: $ 36.38万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-05-01 至 2006-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6510718
• 关键词: Blastomyces dermatitidis; CD28 molecule; CD95 molecule; active immunization; attenuated microorganism; blastomycosis; cellular immunity; cytolysis; cytotoxic T lymphocyte; expression cloning; fungal antigens; helper T lymphocyte; hybridomas; immunoregulation; interferon gamma; interleukin 12; laboratory mouse; microorganism immunology; pore forming protein; transforming growth factors; tumor necrosis factor alpha

Blastomycosis, one of the principal systemic mycoses, often produces a progressive pulmonary disease, but the factors that account for immune failure and resistance during infection with Blastomyces dermatitidis infection are ill defined. We created a WI-1 knockout of B. dermatitidis that is attenuated and controlled in a murine model of primary pulmonary infection. Its administration to mice vaccinates them against re-infection and evokes sterilizing immunity. We propose here to use the isogenic attenuated and wild-type strains and mouse models developed in the last funding period to define the cellular and molecular bases of immune failure and resistance in experimental pulmonary blastomycosis. We hypothesize: that B. dermatitidis subverts generation of immune T-cells in a nonimmune host, leading to progressive infection. In a vaccinated host, T-cells mediate resistance, and show plasticity in the requirements of T-cell subsets for generation and maintenance of vaccine immunity and memory. Our specific aims are to: (1) Decipher the role of the immunosuppressive cytokine transforming growth factor-beta (TGF- beta) in failure of T-cell immunity during progressive primary infection, and the participation of CTLA-4, a negative regulator of T-cell activation, during TGF-beta-induced cellular immune suppression. (2) Delineate differential mechanisms - cytokines (IFN-gamma, TNF-alpha), cytolysis, and direct antimicrobial activity - by which CD4+ and CD8+ T-cells mediate vaccine immunity to B. dermatitidis, and requirements for CD28 co- stimulation and IL-12 signaling in generating and maintaining these recall immune responses. (3) Identify and clone antigens that protective T-cells recognize in vitro from expressed products of a B. dermatitidis cDNA library, and in T-cell immunoblots of a crude, protective cell-wall membrane antigen, and demonstrate that the cloned recombinant antigens confer protective immunity in vivo to B. dermatitidis. Understanding mechanisms of immune failure and resistance to fungi will assist in planning vaccine and treatment strategies in healthy people, and in patients with impairments of host defense such as AIDS.

芽生菌病是主要的系统性真菌病之一，通常会产生进行性肺部疾病，但在皮炎芽生菌感染期间导致免疫失败和耐药性的因素尚不明确。 我们创建了皮炎芽孢杆菌的 WI-1 敲除模型，该模型在原发性肺部感染的小鼠模型中得到减弱和控制。 将其注射到小鼠身上可以使它们接种疫苗以防止再次感染并激发消毒免疫力。 我们在此建议使用上一个资助期开发的同基因减毒和野生型菌株以及小鼠模型来定义实验性肺芽生菌病免疫失败和耐药性的细胞和分子基础。我们假设：皮炎芽孢杆菌会破坏非免疫宿主体内免疫 T 细胞的生成，从而导致进行性感染。 在接种疫苗的宿主中，T 细胞介导抵抗力，并在 T 细胞亚群产生和维持疫苗免疫力和记忆的需求方面表现出可塑性。我们的具体目标是：（1）破译免疫抑制性细胞因子转化生长因子-β（TGF-β）在进行性原发性感染期间 T 细胞免疫失败中的作用，以及 T 细胞活化的负调节因子 CTLA-4 在 TGF-β 诱导的细胞免疫抑制过程中的参与。 (2) 描述不同的机制 - 细胞因子（IFN-γ、TNF-α）、细胞溶解和直接抗菌活性 - CD4+ 和 CD8+ T 细胞通过这些机制介导对皮炎芽孢杆菌的疫苗免疫，以及 CD28 共刺激和 IL-12 信号传导在产生和维持这些记忆免疫反应中的要求。 (3) 从皮炎芽孢杆菌 cDNA 文库的表达产物以及粗制保护性细胞壁膜抗原的 T 细胞免疫印迹中鉴定并克隆保护性 T 细胞在体外识别的抗原，并证明克隆的重组抗原在体内赋予皮炎芽孢杆菌保护性免疫。了解免疫失败和真菌抗性的机制将有助于为健康人群以及艾滋病等宿主防御受损的患者规划疫苗和治疗策略。