Regulation of Mucosal Immunity by Pro- and Anti-inflammatory Salivary Defensins

描述(由申请人提供)：该项目的长期目标是确定唾液的特性，使口腔对艾滋病毒具有独特的抵抗力和免疫反应性。以往的研究表明，防御素是一种参与先天免疫的宿主防御肽，能够直接抑制易感靶细胞的HIV感染。此外，防御素还能激活天然免疫和获得性免疫元件(T细胞、单核细胞、巨噬细胞、树突状细胞)，从而为获得针对各种微生物病原体的体液免疫和/或细胞免疫提供必要的信号。 防御素产生于人类和非人类灵长类动物的唾液中。该项目旨在表征唾液防御素在调节恒河猴口腔免疫反应中的作用。恒河猴是一种灵长类动物，对SIV感染的临床反应与在人类HIV感染中观察到的非常相似。PI实验室最近的研究表明，除了防御素亚类的直接抗HIV活性外，这些多肽还具有深刻的免疫调节活性。我们假设，唾液防御素的免疫调节在口腔粘膜中建立了一个独特的免疫环境，决定了宿主对HIV暴露的早期反应。了解防御素和口腔粘膜细胞成分之间的相互作用将有助于深入了解决定口腔中SIV免疫反应的相互作用网络。为了实现这些目标，我们提出了以下具体目标：1)定量健康和慢性SIV感染猕猴全唾液中α、β和β-防御素的含量；2)在存在或不存在防御性全唾液的情况下，测定单个和组合多肽的生理浓度的抗SIV活性；3)确定单独和联合唾液防御素对PBMC、单核细胞、单核细胞来源的巨噬细胞、单核细胞来源的树突状细胞和CD4+淋巴细胞的激活模式的影响；4)评价唾液防御素对口腔上皮细胞感染HIV的影响，口腔上皮对细菌抗原的反应，以及HIV从口腔上皮细胞向允许的CD4+靶细胞的转运。综上所述，这些研究将为恒河猴口腔免疫的独特特征提供新的见解，从而指导SIV和HIV疫苗开发的临床前方法。 公共卫生相关性：口腔暴露于艾滋病毒很少会导致成人感染。此外，接触过艾滋病毒但仍未感染的患者唾液中存在的抗体似乎具有保护性。该项目试图了解唾液中产生的小蛋白(防御素)如何影响口腔对艾滋病毒感染的抵抗力，以及它们如何在抗艾滋病毒疫苗的设计中有用。

DESCRIPTION (provided by applicant): The long term objective of this project is to determine the properties of saliva that endow the oral cavity with unique resistance and immunologic responsiveness to HIV. Previous studies have demonstrated that defensins, host defense peptides involved in innate immunity, are capable of directly inhibiting HIV infection of susceptible target cells. In addition, defensins are known to activate elements of innate and adaptive immunity (T-cells, monocytes, macrophages, dendritic cells), thus providing signals essential for the acquisition of humoral and/or cell-mediated immunity against a variety of microbial pathogens. Defensins are produced in saliva of humans and non-human primates. This project seeks to characterize the role of salivary defensins in regulating immune responses in the oral cavity of rhesus macaques, a primate with a clinical response to SIV infection that is quite similar to that observed in human HIV infection. Recent studies in the PI's laboratory have demonstrated that, in addition to direct anti-HIV activity of defensin subclasses, these peptides also have profound immunomodulatory activities. We hypothesize that immunoregulation by salivary defensins establishes a unique immunologic milieu in oral mucosa that determines the early response of the host to HIV exposure. An understanding of the interactions between defensins and cellular elements of the oral mucosa will provide insights into the network of interactions that determine the immune responses to SIV in the oral cavity. To achieve these objectives, we propose the following Specific Aims: 1) Quantify the a, ¿, and ?-defensin content in whole saliva of healthy and chronically SIV-infected macaques; 2) determine the anti-SIV activity of physiologic concentrations of individual and combined peptides in the presence or absence of defensindepleted whole saliva; 3) determine the effect of individual and combined salivary defensins on the activation profile of PBMCs, monocytes, monocyte-derived macrophages, monocyte-derived dendritic cells, and CD4+ lymphocytes; and 4) Evaluate the effect of salivary defensins on the infectivity of HIV of oral epithelial cells, the response of oral epithelium to bacterial antigens, and the transport of HIV from the epithelial cells to permissive CD4+ target cells. Taken together, these studies will provide new insights into the unique features of immunity in the oral cavity of rhesus monkeys, thereby guiding preclinical approaches to SIV and HIV vaccine development. PUBLIC HEALTH RELEVANCE: Oral exposure to HIV rarely results in infection in adults. Moreover, antibodies present in the saliva of patients who have been exposed to HIV but who remain uninfected, appear to be protective. This project seeks to understand how small proteins (defensins) produced in saliva influence the resistance of the oral cavity to HIV infection, and how they may be useful in the design of anti-HIV vaccines.