Mtb uptake and antigen presentation in human lung epithelial cells

描述（由申请人提供）： 结核病仍然是全世界传染病发病率和死亡率的一个重要原因，也是武装部队人员特别关注的一个问题。引起结核病的微生物，结核分枝杆菌（Mtb），是一种细胞内病原体。对免疫系统识别细胞内感染的那些机制的改进的定义提供了对改进的疫苗和诊断的直接应用。在这项提案中，我们将定义人肺上皮细胞吸收Mtb的机制，以及Mtb抗原在MHC I类分子MR1的背景下被加工和呈递给肺驻留CD8+ T细胞（称为MAIT细胞）的途径。虽然肺上皮是抵抗结核分枝杆菌感染的第一道防线，但对上皮细胞向先天性T细胞的摄取和抗原呈递机制知之甚少。提高我们对这种相互作用的理解对于合理设计更好的疫苗以服务于VA患者使命至关重要。为了确定人肺上皮细胞被摄取的机制，我们将对体外人上皮细胞中的Mtb区室进行详细分析，涉及已知与摄取、囊泡运输和抗原加工和呈递相关的蛋白质。为了表征上皮细胞Mtb隔室在MR 1抗原呈递中所起的作用，我们将对MR 1的细胞定位、与Mtb隔室的关联以及抗原加工和呈递途径进行详细分析。我们的假设是，结核分枝杆菌是由上皮细胞进入隔室，是不同的专业抗原呈递细胞的吞噬体，和运输和MR 1上的抗原呈递是必要的步骤，在启动和维持结核分枝杆菌特异性粘膜免疫。

DESCRIPTION (provided by applicant): Tuberculosis remains an important cause of infectious disease morbidity and mortality worldwide, and is a problem of particular concern to those in the armed forces. The organism that causes tuberculosis, Mycobacterium tuberculosis (Mtb), is an intracellular pathogen. Improved definition of those mechanisms by which the immune system recognizes intracellular infection provides direct application to improved vaccines and diagnostics. In this proposal, we will define the mechanisms by which human lung epithelial cells take up Mtb and the pathways by which Mtb antigens are processed and presented in the context of the MHC Class I molecule, MR1, to lung resident CD8+ T cells known as MAIT cells (mucosal-associated invariant T cells). Although the lung epithelium is the first line of defense against infection with Mtb, very little is known about the mechanisms of uptake and antigen presentation by epithelial cells to innate T cells. Improving our understanding of this interaction will be critical to rational design of better vaccines to serve the VA patient mission. To define the mechanisms by which human lung epithelial cells are taken up, we will perform a detailed analysis of the Mtb compartment in human epithelial cells in vitro, with regard to proteins known to be associated with uptake, vesicular trafficking, and antigen processing and presentation. To characterize the role that the epithelial cell Mtb compartment plays in MR1 antigen presentation, we will perform a detailed analysis of MR1 with regard to its cellular localization, association with the Mtb compartment, and antigen processing and presentation pathways. Our hypothesis is that Mtb is taken up by epithelial cells into compartments that are distinct from phagosomes of professional antigen presenting cells, and that trafficking of and presentation of antigen on MR1 are requisite steps in initiation and maintenance of Mtb-specific mucosal immunity.