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）正在开发作为对抗感染和癌症的疫苗载体。此类疫苗可具有针对粘膜病原体以及针对肿瘤的特定效用，因为LM感染诱导了稳健的CD4和CD8 T细胞应答。此外，表达异源蛋白的重组LM通过诱导其他保护机制，如抗体应答，具有作为针对各种全身或粘膜感染的疫苗的潜力。在该提议中要测试的总体假设是，在肠粘膜的适应性免疫应答期间，调节信号和炎症信号之间的复杂相互作用将导致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细胞对感染的应答，特别是使用全身给药的LM，已经了解了很多，但是关于肠粘膜对口腔感染的免疫应答，这是这种和许多其他人类病原体的自然感染途径，知之甚少。已经进行的研究使用野生型（WT）LM（一种人源菌株）感染小鼠。这是一个问题，因为WT内化蛋白A（结合肠上皮细胞E-钙粘蛋白（E-cad）以允许细菌侵入的受体）对人E-cad具有高亲和力，但与小鼠E-cad结合差。该提议利用新开发的重组LM，其表达以高亲和力结合小鼠E-cad的修饰的内化蛋白A蛋白（InlAM rLM），从而允许肠上皮的感染和随后的细菌传播。因此，LM免疫的免疫应答现在可以在自然环境中研究，更接近于人类感染。我们将使用该系统来确定InlAM rLM疫苗接种保护免受同源和异源感染的功效，并在三个特定目标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贡献：目标1：确定LM疫苗接种的功能结果。目的2：确定口服LM疫苗对同种和异种感染的保护作用。目的3：确定粘膜记忆T细胞亚群对对抗攻击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.