The Role of CD1a in Protecting Against Human Tuberculosis

申请人是传染病专家，长期关注结核病和国际卫生。他在基础和临床研究方面的背景是拟议研究的基础。作为霍华德休斯研究学者，他在美国国立卫生研究院研究了基本的T细胞免疫学，并作为哈佛的研究员研究了CD 1分子的脂质抗原呈递。作为一名住院医生，他协助在急诊室进行急性和慢性未确诊艾滋病毒的流行率研究。他还在坦桑尼亚设计、资助、执行并发表了一项结核病体外诊断的现场试验。他的近期目标是研究脂质抗原呈递在结核病疫苗免疫和临床反应中的作用。他将使用一些专门的资源作为培训计划的一部分来实现这一目标。首先，拟议的导师（托马斯霍恩博士）具有研究大型人类群体中常见遗传变异的经验，这些经验将首次应用于CD 1系统。第二，他将与Willem Hanekom博士合作，后者在南非建立了一个由5000名接种疫苗的婴儿组成的前瞻性队列。第三，他将与分支穆迪博士合作进行免疫学研究，穆迪博士已经鉴定并合成了许多CD 1限制性分枝杆菌脂质抗原。申请人的长期目标是在学术中心的传染病部门寻求临床任命，他将投入至少75%的精力管理实验室和/或合作临床研究。 T细胞对M.已经在人群中鉴定和研究了在多态性MHC分子背景下呈递的结核特异性肽。而M.结核病还含有许多独特的脂质，其在CD 1分子的背景下呈递给T细胞。卡介苗（BCG）是目前唯一注册的结核病疫苗，可预防儿童早期严重的结核病。卡介苗接种后是否诱导了CD 1抗原特异性T细胞，并与结核病的保护有关，目前尚不清楚。与已知具有遗传和功能多态性的MHC分子相比，CD 1被认为显示有限的变异性。CD 1基因座中的5个基因（CD 1a、CD 1b、CD 1c、CD 1d和CD 1 e）的遗传变异与结核病易感性之间的关联也尚不清楚。拟议导师的实验室，博士托马斯R。Hawn，已经确定了先天免疫基因中的单核苷酸多态性（SNP），并进行了功能研究以阐明功能表型的丧失。这些方法将用于研究CD 1a在接种卡介苗的南非婴儿中预防结核病的作用。 初步数据表明，一些感染M。结核病不能在单核细胞来源的树突状细胞表面表达CD 1a以响应炎性细胞因子。因此，申请人将首先研究CD 1a基因调控和表达的机制。双脱氧分枝杆菌素（DDM）是一种CD 1a特异性分枝杆菌抗原，由分支穆迪博士鉴定，并在活动性结核病成人患者中进行了研究，如初步数据所报告。申请方将与Moody博士合作，确定卡介苗接种后是否诱导了DDM特异性T细胞，以及这些反应是否与保护相关。最后，申请人已经确定了CD 1a多态性与成人结核病结局之间的关联。他建议研究这些多态性对基因表达和抗原呈递的影响。他还将研究这些多态性与卡介苗接种婴儿的免疫学和临床结果的关系。缺乏预防结核病的免疫相关物阻碍了新药和疫苗的开发。本文提出的工作将直接评估CD 1介导的脂质抗原呈递作为抗结核保护的相关因素的贡献。 这项工作将在西雅图的华盛顿大学医学院进行。申请人和拟议的导师是在过敏和传染病的部门，其中包括73名全职教师，其总赠款支持超过每年1.35亿美元。该司是一个理想的环境，培养医生，科学家，因为超过80%的过去的奖学金学员已获得教师职位，在学术医学。申请人提出的研究利用了他在T细胞免疫学和脂质生物化学方面的强大背景，但需要在分子生物学，先天免疫学和人类遗传学方面进行额外的培训。他有详细的课程，研讨会和会议，以满足这些需求。他还组建了一个科学咨询小组，提供一对一的专业知识。最后，拟议的导师有一个证明这些技术的跟踪记录，并成功地指导其他初级科学家。

The applicant is a specialist in infectious diseases with a long-term interest in tuberculosis and international health. His background in basic and clinical research is the basis for the proposed research. He studied basic T-cell immunology at the NIH as a Howard Hughes Research Scholar and lipid antigen presentation by CD1 molecules as a research fellow at Harvard. As a resident, he assisted in a prevalence study of acute and chronic undiagnosed HIV in emergency rooms. He also designed, funded, executed, and published a field trial of in-vitro diagnostics for tuberculosis in Tanzania. His immediate goals are to study the role of lipid antigen presentation in the immunologic and clinical response to vaccination against tuberculosis. He will accomplish this using a number of specialized resources as part of a training program. First, the proposed mentor (Dr. Thomas Hawn) has experience studying common genetic variation in large human cohorts that will be applied for the first time to the CD1 system. Second, he will collaborate with Dr. Willem Hanekom who has established a prospective cohort of 5000 vaccinated infants in South Africa. Third, he will perform immunologic studies in collaboration with Dr. Branch Moody who has identified and synthesized a number of CD1-restricted mycobacterial lipid antigens. The applicant's long term goals are to seek a clinical appointment in a Division of Infectious Diseases at an academic center where he will devote at least 75% effort to managing a lab and/or collaborative clinical study. T-cell responses to M. tuberculosis specific peptides presented in the context of polymorphic MHC molecules have been identified and studied in human populations. However, the cell wall of M. tuberculosis also contains a number of unique lipids that are presented to T-cells in the context of CD1 molecules. Mycobacterium bovis Bacille Calmette-Guerin (BCG) is the only registered TB vaccine currently available and protects against severe forms of TB in early childhood. Whether CD1 antigen specific T-cells are induced after BCG vaccination and correlate with protection from TB is not known. Compared to MHC molecules which are known for their genetic and functional polymorphism, CD1 is considered to display limited variability. The association between genetic variation of the five genes in the CD1 locus (CD1a, CD1b, CD1c, CD1d, and CD1e) and susceptibility to tuberculosis is also not known. The laboratory of the proposed mentor, Dr. Thomas R. Hawn, has identified single nucleotide polymorphisms (SNPs) in innate immune genes and performed functional studies to elucidate loss of function phenotypes. These methods will be used to study the role of CD1a in protection against tuberculosis in South African infants vaccinated with BCG. Preliminary data suggests that some individuals infected with M. tuberculosis fail to express CD1a on the surface of monocyte-derived dendritic cells in response to inflammatory cytokines. Therefore, the applicant will first investigate the mechanism of CD1a gene regulation and expression. Dideoxymycobactin (DDM) is a CD1a-specific mycobacterial antigen identified by Dr. Branch Moody and studied in adults with active tuberculosis, as reported in the preliminary data. In collaboration with Dr. Moody, the applicant will determine if DDM-specific T-cells are induced after BCG vaccination and whether these responses are associated with protection. Finally, the applicant has identified associations between polymorphisms in CD1a and tuberculosis outcome in adults. He proposes to study the effect of these polymorphisms on gene expression and antigen presentation. He will also study the association of these polymorphisms with immunologic and clinical outcome in the BCG vaccinated infants. The lack of immune correlates of protection against tuberculosis has hindered the development of new drugs and vaccines. The work proposed here will directly assess the contribution of CD1-mediated lipid antigen presentation as a correlate of protection against tuberculosis. This work will be performed at the University of Washington School of Medicine in Seattle. The applicant and proposed mentor are in the Division of Allergy and Infectious Diseases which consists of 73 full- time faculty members whose total grant support exceeds $135 million annually. This Division is an ideal environment for training physician-scientists since more than 80% of past fellowship trainees have obtained faculty positions in academic medicine. The applicant proposed research takes advantage of his strong background in T-cell immunology and lipid biochemistry but requires additional training in molecular biology, innate immunology, and human genetics. He has detailed coursework, seminars, and meetings to address these needs. He has also assembled a scientific advisory panel to provide one-on-one expertise. Finally, the proposed mentor has a demonstrated track record with these techniques and has successfully mentored other junior scientists.