Immune defenses against Neisseria gonorrhoeae

针对淋病奈瑟菌的免疫防御

• 批准号: 8963568
• 负责人: SANJAY RAM
• 金额: $ 62.99万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-05-05 至 2020-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8963568
• 关键词: Address; Affect; Antibiotics; Antibodies; Binding; Ceftriaxone; Centers for Disease Control and Prevention (U.S.); Chemotactic Factors; Clinical; Complement; Complement 3a; Complement 5a; Complement Activation; Complement Factor H; Complement Inactivators; Complement Membrane Attack Complex; Complement Receptor; Contracts; Data; Dependence; Development; Disease; Ectopic Pregnancy; Epitopes; Genital system; Genotype; Glycosyltransferase Gene; Gonorrhea; Human; Human Factor H; Immune; Immune response; Inbred BALB C Mice; Individual; Infection; Infection prevention; Infertility; Knowledge; Light; Location; Measures; Membrane Proteins; Modeling; Molecular; Movement; Mucous Membrane; Mus; Neisseria gonorrhoeae; Opsonin; Pathogenesis; Pelvic Inflammatory Disease; Peptides; Phase; Phenotype; Play; Polysaccharides; Preparation; Proteins; Public Health; Reproductive Health; Resistance; Role; Sexually Transmitted Diseases; Site; Specificity; Structure; Superbug; Surface; Transgenic Mice; Vaccines; Vagina; Variant; Virulence; Woman; Work; arm; bactericide; base; chronic pelvic pain; complement 4b-binding protein; design; fitness; high risk; in vivo; inhibitor/antagonist; killings; lipooligosaccharide; macrophage; mouse model; mutant; neutrophil; novel; novel therapeutics; novel vaccines; pathogen; prevent; public health relevance; receptor; resistant strain; vaccine candidate; vaccine development; vaccine efficacy

 DESCRIPTION (provided by applicant): Neisseria gonorrhoeae (Ng) is the causative agent of the sexually transmitted infection, gonorrhea. Gonorrhea causes over 100 million new cases worldwide annually and adversely affects the reproductive health of women. Ng has become resistant to almost every antibiotic that has been used and has now achieved "superbug" status. Vaccines against Ng are urgently needed. Complement (C) is a critical arm of innate immune defenses against Ng. Gonorrhea is characterized by an influx of polymorphonuclear leukocytes (PMNs) into the genital tract, which in concert with Ab and C may facilitate clearance of infection. Vaccine development against Ng has been hindered by lack of knowledge of the correlates of protection. Our vaccine candidate is a peptide mimic (mimitope) of a Ng lipooligosaccharide (LOS) epitope that elicits bactericidal and opsonophagocytic Ab in mice. In Specific Aim 1, we will elucidate the roles of PMNs, C and C receptors in vaccine Ab efficacy to define the correlates of protection in vivo. Vaccine Ab will be evaluated in mice that lack either PMNs, C3 (opsonin) or C5a (chemotaxin) receptor. Ng binds the C inhibitors, factor H (fH) and C4b- binding protein (C4BP) in a human-specific manner. Binding of human C inhibitors blunts the bactericidal activity of vaccine Ab. We have developed transgenic mice that express both human fH and C4BP, which will be used to evaluate the efficacy of vaccine Ab in vivo and simulate conditions in humans where Ab must surmount human C inhibitors. Ng LOS plays a central role in the pathogenesis of gonorrhea. The ability of Ng to alter its LOS glycan extensions through phase variation contributes to its versatility in immune evasion. We have constructed eight Ng mutants where LOS glycan expression has been 'genotypically fixed'. In Specific Aim 2a the ability of each of these mutants to infect mice will be examined, which will elucidate how defined LOS structures driven by fixed genotypes contribute to bacterial fitness in vivo. In light of our data which show that altering LOS glycans modulates the bactericidal activity of vaccine anti-LOS Ab, we will study the efficacy of the vaccine Ab against each 'fit' LOS genotype in Specific Aim 2b. Studies in Aim 2 will correlate LOS geno/phenotypes with fitness and enable us to identify LOS structures that could supplement our current vaccine candidate. Individuals who possess Ab directed against an Ng conserved and ubiquitous outer membrane protein called reduction modifiable protein (Rmp) show impaired bactericidal activity against Ng and are at a higher risk of contracting gonorrhea. In Specific Aim 3 we will determine the molecular basis whereby Abs directed against Rmp block C-dependent Ab killing of Ng and negatively impact the efficacy of vaccine Ab. Interestingly, anti-Rmp Ab does not block killing of N. meningitidis (Nm). Allelic replacement of rmp across the two species will be performed to define whether subtle sequence differences between Ng and Nm Rmp contribute to differences in blocking across the two pathogens. Corresponding Ng and Nm PorB molecules will also be exchanged across the two species to assess co-dependence of species specific PorB on the blocking effect. Completion of the proposed studies will represent an important step forward in the development of novel vaccines against gonorrhea.

 描述(申请人提供)：淋病奈瑟氏菌(Ng)是性传播感染淋病的病原体。淋病每年在全世界造成1亿以上的新病例，并对妇女的生殖健康造成不利影响。NG已经对几乎所有使用过的抗生素都产生了抗药性，现在已经达到了“超级细菌”的状态。目前迫切需要针对Ng的疫苗。补体(C)是针对Ng的先天免疫防御的关键武器。淋病的特征是多形核白细胞(PMN)涌入生殖道，与抗体和C一起可能有助于感染的清除。由于缺乏对保护相关因素的了解，针对Ng的疫苗开发一直受到阻碍。我们的候选疫苗是一种Ng脂低聚糖(LOS)表位的多肽模拟(模拟表位)，它能在小鼠身上产生杀菌和吞噬细胞抗体。在特定的目标1中，我们将阐明PMN、C和C受体在疫苗抗体效力中的作用，以确定体内保护的相关因素。疫苗抗体将在缺乏PMN、C3(调色素)或C5a(趋化素)受体的小鼠身上进行评估。NG以人类特有的方式与C抑制剂、H因子(Fh)和C4b结合蛋白(C4BP)结合。人C抑制剂的结合可钝化疫苗的杀菌活性。我们已经开发出同时表达人FH和C4BP的转基因小鼠，这将用于评估抗体疫苗在体内的效果，并在人类中模拟抗体必须超过人C抑制剂的条件。NGLOS在淋病的发病机制中起核心作用。Ng通过时相变化改变其葡聚糖延伸的能力有助于其在免疫逃避中的多功能性。我们已经构建了八个Ng突变体，其中LOS多糖的表达已经在基因上得到了固定。在特定的目标2a中，将检查这些突变体中的每一个感染小鼠的能力，这将阐明由固定基因型驱动的明确的LOS结构如何有助于细菌在体内的适合性。根据我们的数据显示，改变低聚糖调节杀菌活性 在抗LOS抗体的疫苗中，我们将针对特定的目标2b来研究疫苗抗体对每一种“适合”的LOS基因的效力。AIM 2的研究将使LOS基因/表型与适合性相关，并使我们能够识别可以补充我们当前候选疫苗的LOS结构。拥有针对Ng保守且普遍存在的外膜蛋白(RMP)的抗体的人对Ng的杀菌活性减弱，感染淋病的风险更高。在具体目标3中，我们将确定针对RMP的抗体阻断C依赖的抗体对Ng的杀伤并对疫苗抗体的效力产生负面影响的分子基础。有趣的是，抗RMP抗体并不能阻止对脑膜炎奈瑟菌(Nm)的杀灭。将进行两个物种中RMP的等位基因替换，以确定Ng和Nm RMP之间的细微序列差异是否有助于跨两个病原体的阻断差异。相应的Ng和Nm PorB分子也将在两个物种之间交换，以评估物种特异性PorB对阻断效应的相互依赖。拟议研究的完成将代表着在开发新型淋病疫苗方面向前迈出的重要一步。