Immune reconstitution to Aspergillus

描述（由申请人提供）：同种异体造血干细胞（HCT）受体侵袭性曲霉病（IA）的年发病率为10%至15%，死亡率约为80%；因此，这种感染已成为HCT后感染相关死亡的主要原因。感染现在主要发生在异基因HCT过程的晚期，在中性粒细胞移植后。流行病学与最近的认识一致，即动物模型中有效的免疫需要强大的CD4+ T辅助1型（Th1）应答。然而，尚无大型研究对曲霉特异性免疫重建进行评估。我们已经开发了测量细胞对曲霉抗原反应的方法，并在健康志愿者中证明了可重复的可变反应。我们提出了一项纵向免疫重建研究，以评估CD4+ T细胞重建对同种异体HCT后晚期IA的保护作用，包括供体转移免疫在内的多种因素可能影响免疫重建。具体目标将是：1。确定重建的细胞免疫是否能预测IA的风险和结果。患者将被纳入一项纵向研究，以评估重组细胞数量（DC1、DC2、T细胞亚型、NK细胞和B细胞）和对烟曲霉菌丝抗原的功能反应是否能预测IA的风险和预后。在目标2中，研究将确定在健康供体中不同频率的反应性CD4+ T细胞和细胞因子模式的意义。将对供体反应进行评估，以验证健康人体内产生ifn - γ的CD4+ T细胞的低频率与MHC等位基因相关的假设，可能包括特定的II类单倍型和/或III类区域（tnf - α基因）的多态性。将评价捐助国的反应对受援国重建的影响。Aim 3的研究将鉴定烟曲霉抗原呈递给健康的人类CD4+ T细胞。曲霉特异性CD4+ T细胞克隆将通过连续刺激菌丝抗原从健康受试者中产生。经典的hla限制性CD4+克隆将用于筛选烟曲霉cDNA的汇集文库，顺序筛选单个t细胞抗原。本研究的目的是确定移植后对曲霉的免疫保护机制。这一信息将有助于制定预防和治疗免疫功能低下人群真菌感染的策略。

DESCRIPTION (provided by applicant): The annual incidence of invasive aspergillosis (IA) ranges from 10 to15% in allogeneic hematopoietic stem cell (HCT) recipients, with mortality approximating 80%; as such, this infection has become a prominent cause of infection-related death after HCT. Infection now occurs primarily late in the course of allogeneic HCT, after neutrophil engraftment. Epidemiology is consistent with the recent recognition that effective immunity in animal models requires robust CD4+ T helper type-1 (Th1) responses. However, no large studies have been performed to evaluate Aspergillus-specific immune reconstitution. We have developed the methods to measure cellular responses to Aspergillus antigens, and demonstrated reproducibly variable responses in healthy volunteers. We propose a longitudinal immune-reconstitution study to evaluate the hypothesis that CD4+ T cell reconstitution is important to protect from IA late after allogeneic HCT, with multiple factors, including donor transferred immunity, potentially impacting immune reconstitution. Specific aims will be to: 1. Determine if reconstituted cellular immunity predicts risks for, and outcomes of IA. Patients will be enrolled in a longitudinal study to evaluate whether reconstituted cell numbers (DC1, DC2, T cell subtypes, NK cells and B cells) and functional responses to A. fumigatus hyphal antigen predict risks for, and outcomes of IA. In Aim 2, studies will determine the significance of variable frequencies of reactive CD4+ T cells and cytokine patterns in healthy donors. Donor responses will be evaluated to test the hypothesis that low frequencies of IFN-gamma producing CD4+ T cells in healthy people are associated with MHC alleles, potentially including specific Class II haplotypes and/or polymorphism(s) in the Class III region (TNF-alpha gene). The impact of donor responses on recipient reconstitution will be evaluated. Studies in Aim 3 will identify Aspergillus fumigatus antigens presented to healthy human CD4+ T cells. Aspergillus-specific CD4+ T cell clones will be generated from healthy subjects by sequential stimulation with hyphal antigens. Classical HLA-restricted CD4+ clones will be used to screen pooled libraries of A. fumigatus cDNA, with sequential screens identifying individual T-cell antigens. This study will be performed with the goal of defining the mechanisms of post-transplant immune protection against Aspergillus species. This information will be valuable for development of strategies to prevent and treat fungal infections in immunocompromised people.