Gonococcal interactions with human polymorphonuclear leukocytes

描述(申请人提供)：由淋球菌(GC)引起的急性淋病感染，以大量多形核白细胞(PMN)募集到泌尿生殖道为特征。然而，在PMN存在的情况下，感染仍然存在，这表明GC已经进化出了阻止PMN杀伤的方法。支持这些观察结果的是，我已经证明了GC可以在PMN存在的情况下存活，而且确实发生的杀伤是非氧化性的。我研究的目的是阐明是什么让一些GC在PMN暴露下存活下来，并确定导致剩余GC死亡的PMN因素。在提案的目标1中，我将通过量化附着在PMN上并被PMN内化的GC的活性，并检测GC与PMN颗粒、溶酶体和中性粒细胞外陷阱的共存，来确定与PMN相关的GC的亚细胞定位如何影响细菌存活。在目标2中，我将通过分析暴露于单个PMN因子和PMN颗粒组分后的GC存活率来鉴定PMN的杀菌成分。在这些研究中，我将比较野生型GC和更容易受到PMN杀伤的两个突变体(ngo1686和recN)，这将为野生型GC如何在PMN下生存以及ngo1686和recN基因产物如何帮助GC生存提供解释。十年来，我一直在研究粘膜病原体与宿主细胞的相互作用，从研究生开始，继续作为H.Steven Seifert博士的博士后研究员。在团契期间，我的研究重点从帮助GC逃避适应性免疫反应的Pilin抗原变异，演变到GC如何避免PMN清除，这是GC发病机制中一个关键但知之甚少的方面。我的直接职业目标，将在指导阶段完成，是完成GC-PMN相互作用的初步研究，这将为获得独立的教员职位奠定基础。这将支持我的长期职业目标，指导一个实验室进行前沿的GC发病机制研究。与公共健康相关：淋病是美国和世界范围内第二大流行的性传播疾病。感染导致男性和女性生殖道结疤和不育，以及婴儿失明，淋病患者更容易感染艾滋病毒。了解在急性淋病感染期间宿主免疫反应是如何被颠覆的，这是寻找治疗这种疾病的新疗法的关键第一步。

DESCRIPTION (provided by applicant): Acute gonorrheal infection, caused by Neisseria gonorrhoeae (Gc), is characterized by the recruitment of massive numbers of polymorphonuclear leukocytes (PMNs) to the urogenital tract. However, infection persists in the presence of PMNs, suggesting Gc have evolved ways to thwart PMN killing. Supporting these observations, I have shown that Gc can survive in the presence of PMNs and that the killing that does occur is non-oxidative. The goals of my research are to elucidate what allows some Gc to survive exposure to PMNs and to identify the PMN factors that kill the remaining Gc. In Aim 1 of the proposal, I will determine how the subcellular localization of Gc associated with PMNs affects bacterial survival, by quantifying the viability of Gc adherent to and internalized by PMNs and examining the colocalization of Gc with PMN granules, lysosomes, and neutrophil extracellular traps. In Aim 2, I will identify the bactericidal components of PMNs that are active against Gc by assaying Gc survival after exposure to individual PMN factors and to PMN granule fractions. In these studies I will compare wild-type Gc to two mutants that are more susceptible to PMN killing (ngo1686 and recN), which will provide explanations for how wild-type Gc survive exposure to PMNs and how the ngo1686 and recN gene products aid in Gc survival. I have been studying the interplay of mucosal pathogens with host cells for ten years, beginning with graduate studies and continuing as a postdoctoral fellow with Dr. H. Steven Seifert. During the fellowship period, my research focus has evolved from pilin antigenic variation, which aids Gc in evading the adaptive immune response, to how Gc avoid PMN clearance, a crucial yet poorly understood aspect of pathogenesis of Gc. My immediate career goal, to be completed in the mentored phase, is to complete initial studies of Gc-PMN interactions that will lay the foundation for obtaining an independent faculty position. This will support my long-term career goal, to direct a laboratory performing cutting-edge Gc pathogenesis research. RELEVANCE TO PUBLIC HEALTH: Gonorrhea is the second-most prevalent sexually transmitted disease in the US and worldwide. Infection causes reproductive tract scarring and sterility in both men and women and blindness in infants, and individuals with gonorrhea are more susceptible to HIV infection. Understanding how the host immune response is subverted during acute gonorrheal infection is a critical first step in finding new therapies for treatment of this disease.