T Cell Response to Listeria Monocytogenes Infection

描述(由申请人提供)：单核细胞增生性李斯特菌(Lm)(一种第二类生物防御病原体)正被开发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CD8T细胞反应。此外，表达异源蛋白的重组LM通过诱导抗体反应等其他保护机制，有可能作为疫苗对抗各种全身或粘膜感染。在这项提议中要检验的总体假设是，调控信号和炎症信号之间的复杂相互作用将导致在肠道粘膜的适应性免疫反应期间产生不同的细胞和体液结果，这将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，特别是使用全身给药的LM，已经了解了很多，但对口腔感染的肠道粘膜免疫反应知之甚少，口腔感染是这种疾病和许多其他人类病原体的自然感染途径。已经完成的研究使用了野生型(WT)LM，这是一种来自人类的菌株，用来感染小鼠。这是一个问题，因为WT内分泌素A是一种与肠上皮细胞E-钙粘素(E-cad)结合以允许细菌入侵的受体，与人E-cad有很高的亲和力，但与小鼠E-cad结合较差。这一建议利用新开发的表达修饰的内源性A蛋白(InlAM RLM)的重组LM以高亲和力结合小鼠E-cad，从而允许肠道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疫苗对同种和异种感染的保护效果，并从三个特定目的分析迁移性和组织驻留记忆T细胞在介导肠道或肺保护中的作用：目的1：确定LM疫苗的功能结果。目的2：确定口服LM疫苗对同源和异源感染的保护效果。目的3：探讨粘膜记忆T细胞亚群对攻击感染的二级保护作用。

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.