T Cell Response to Listeria Monocytogenes Infection

描述（由申请人提供）：单核细胞增生李斯特菌（LM）（2类生物防御病原体）正在被开发作为对抗感染和癌症的疫苗载体。这种疫苗可能对粘膜病原体和肿瘤具有特殊的效用，因为LM感染诱导了强大的CD4和CD8 T细胞反应。此外，表达异源蛋白的重组LM有可能通过诱导其他保护机制（如抗体反应）作为抗多种全身或粘膜感染的疫苗。本研究的主要假设是，调节信号和炎症信号之间的复杂相互作用将导致肠黏膜适应性免疫反应中不同的细胞和体液结果，从而影响其他部位的免疫。尽管近年来关于T细胞对感染的反应已经有了很多了解，特别是使用系统给药的LM，但对于肠道黏膜对口腔感染的免疫反应，以及这种和许多其他人类病原体的自然感染途径知之甚少。所做的研究使用野生型（WT） LM，这是一种人类衍生的菌株，感染小鼠。这是一个问题，因为WT内毒素A，一种与肠上皮细胞e -钙粘蛋白（E-cad）结合以允许细菌入侵的受体，对人类E-cad具有高亲和力，但对小鼠E-cad结合较差。本研究利用了一种新开发的重组LM，表达了一种修饰的内毒素a蛋白（InlAM rLM），该蛋白高亲和力地结合小鼠E-cad，从而允许肠上皮感染和随后的细菌传播。因此，现在可以在与人类感染更接近的自然环境中研究对LM免疫的免疫反应。我们将使用该系统来确定InlAM rLM疫苗接种对同源和异源感染的保护效果，并在三个特定目的中剖析迁移和组织驻留记忆T细胞在肠或肺中介导保护的作用：目的1：确定LM疫苗接种的功能结果。目的2：确定口服LM疫苗预防同源和异源感染的效果。目的3：确定粘膜记忆T细胞亚群对抗侵袭性感染的二级保护的贡献。

DESCRIPTION (provided by applicant): Listeria monocytogenes (LM) (a category 2 Biodefense pathogen) is being developed as a vaccine vehicle for combating infection as well as cancer. Such vaccines may have particular utility against mucosal pathogens as well as against tumors since robust CD4 and CD8 T cell responses are induced by LM infection. In addition, recombinant LM expressing heterologous proteins have potential as vaccines against a variety of systemic or mucosal infections by inducing other protective mechanisms, such as antibody responses. The overarching hypothesis to be tested in this proposal is that a complex interplay between regulatory and inflammatory signals will result in distinct cellular and humoral outcomes during an adaptive immune response in the intestinal mucosa that will affect immunity at other sites. Although much has been learned in recent years with regard to the T cell response to infection, particularly using systemically administered LM, little is known regarding the intestinal mucosal immune response to oral infection, the natural infection route for this and many other human pathogens. What studies have been done used wild-type (WT) LM, which is a human- derived strain, to infect mice. This is an issue since WT internalin A, the receptor that binds to intestinal epithelial cell E-cadherin (E-cad) to allow bacterial invasion, has high affiniy for human E-cad but binds poorly to mouse E-cad. This proposal utilizes a newly developed recombinant LM expressing a modified internalin A protein (InlAM rLM) that binds mouse E-cad with high affinity, thereby allowing infection of the intestinal epithelium and subsequent bacteria dissemination. Thus, the immune response to LM immunization can now be studied in a natural setting more closely paralleling human infection. We will use this system to determine the efficacy of InlAM rLM vaccination to protect against homologous and heterologous infections and to dissect the contribution of migrating and tissue resident memory T cells in mediating protection in the intestine or lung in three specific aims: Aim 1: Determine the functional outcome of LM vaccination. Aim 2: Determine the efficacy of oral LM vaccination in protection against homologous and heterologous infections. Aim 3: To determine the contribution of mucosal memory T cell subsets to secondary protection against challenge infections.