Outer Membrance Protein vaccinogens of Treponema pallium

梅毒是一种由梅毒螺旋体亚种引起的性传播感染。梅毒(TPA)，有 自20世纪90年代末以来，美国经历了戏剧性的复兴。梅毒也是一大威胁。 全球每年估计有560万新病例和350,000例不良妊娠结局 母婴传播。人们越来越感到有必要接种梅毒疫苗作为一种 这是全球遏制战略的基石。我们开发梅毒疫苗的探索始于 认识到TPA的外膜(OM)与原型革兰氏的外膜(OM)有根本的不同 阴性菌，如大肠杆菌。我们假设TPA的非正统OM是其令人印象深刻的基础 免疫逃避能力与TPA稀有OM生成蛋白(OMP)谱鉴定 掌握着疫苗研发的关键。 所有先前测试的抗原最多只能产生有限的保护作用，这表明梅毒 疫苗将需要多种成分，因此需要一条候选疫苗原管道来 确定提供最大广度和程度的本地和系统保护的组合。尽管 基因组序列的可用性，直到最近，梅毒学者还无法对螺旋体进行分类 ‘OMPeome’。突破是通过使用生物信息学、计算和结构算法来挖掘 TPA基因组中的蛋白质被预测形成一个两亲性的b桶，这是OM跨越的结构标志 蛋白质。通过这种方法，我们在TPA中确定了20个候选OMP，它们分为两类：Tprs和a 一组不相关的(‘非Tpr’)b桶形成蛋白。对于几个(TP0326/BAMA和TPRR成员 亚家族I)，b桶的形成和OM在TPA中的定位已经通过严格的实验得到验证， 它们诱导强大的光学活性的能力也得到了证明。我们的建议采用了 不偏不倚的新方向：作为保护性抗原的光学靶标：领先的OMP疫苗原候选 是基于基因组序列、生物信息学、生物物理分析和结构建模来选择的，而不是 而不是它们是否被感染期间产生的免疫血清识别。我们的流水线包括OMPS 来自四个“团体”：巴马、亚科I和亚科II Tprs以及Fadl。在目标1中，我们将完善我们的拓扑和 Tpr亚家族和Fadl组领先候选人的结构模型。在目标2中，我们将评估 抗一个或多个候选OMP的高滴度抗血清促进TPA(体外)的吞噬作用 相关保护)使用兔和小鼠巨噬细胞。在目标3中，我们将在兔子身上进行测试，并在 对小鼠的探索性研究，如果用一个或多个OMP免疫可以提供广泛和强大的 用不同的TPA菌株挑战后的保护。

Syphilis, a sexually transmitted infection caused by the Treponema pallidum subsp. pallidum (TPA), has undergone a dramatic resurgence in the United States since the late 1990s. Syphilis also poses a major threat globally with an estimated 5.6 million new cases annually and 350,000 adverse pregnancy outcomes due to mother-to-child transmission. There is a growing sense of urgency about the need for a syphilis vaccine as a cornerstone of a strategy for global containment. Our quest to develop a syphilis vaccine began with the recognition that the outer membrane (OM) of TPA differs fundamentally from those of prototypical Gram- negative bacteria, such as E. coli. We hypothesized that TPA's `unorthodox' OM is the basis for its impressive capacity for immune evasion and that identification of TPA's repertoire of rare OM-spanning proteins (OMPs) holds the key to vaccine development. The ability of all previously tested antigens to confer at best only limited protection suggests that a syphilis vaccine will require multiple components and, consequently, the need for a pipeline of candidate vaccinogens to identify the combination that provides the greatest breadth and degree of local and systemic protection. Despite the availability of genomic sequences, until recently, syphilologists were unable to catalog the spirochete's `OMPeome'. The breakthrough came by using bioinformatics, computational, and structural algorithms to mine the TPA genome for proteins predicted to form an amphiphilic b-barrel, the structural hallmark of OM-spanning proteins. With this approach, we identified 20 candidate OMPs in TPA, which fall into two `classes': Tprs and a group of unrelated (`non-Tpr') b-barrel-forming proteins. For several (TP0326/BamA and members of Tpr subfamily I), b-barrel formation and OM localization in TPA has been validated by rigorous experimentation, and their ability to elicit potent opsonic activity also has been demonstrated. Our proposal takes the notion of `opsonic target as protective antigen' in an unbiased and novel direction: leading candidate OMP vaccinogens are selected based on genomic sequences, bioinformatics, biophysical analysis, and structural modeling, rather than whether they are recognized by immune sera generated during infection. Our pipeline consists of OMPs from four `groups': BamA, subfamily I and II Tprs, and the FadLs. In Aim 1, we will refine our topological and structural models for leading candidates in the Tpr subfamilies and FadL groups. In Aim 2, we will assess whether high titer antisera against one or more candidate OMPs promote opsonophagocytosis of TPA (an ex vivo correlate of protection) using rabbit and mouse macrophages. In Aim 3, we will determine in rabbits, and in exploratory studies with mice, if immunization with one or more OMPs provides broad as well as strong protection following challenge with diverse strains of TPA.