MOMP-based recombinant antigens for a Chlamydia vaccine

该项目的总体目标是开发一种针对衣原体的疫苗。沙眼衣原体(Ct)是一种 专性胞内革兰氏阴性菌和细菌性传播的最常见原因 全世界的性传播感染(STI)。女性CT感染会导致长期的后遗症，即盆腔炎 (PID)、宫外孕和不孕症，并经常与其他性传播感染(艾滋病毒、人乳头瘤病毒、淋病和 梅毒)。抗生素并不能防止感染复发。CT疫苗的研制在很大程度上还没有完成 需要。以前的基于全生物的疫苗对CT眼部感染的保护有限， 一些接种疫苗的个体出现短暂的血清/亚群特异性免疫和超敏反应。 衣原体主要外膜蛋白MOMP是亚单位疫苗的主要候选抗原。 MOMP是一种具有8个表面暴露环的三聚体孔蛋白，包含序列可变性区域(可变结构域， 环2、3、5和6内的VDS)和侧翼的恒定氨基酸序列(恒定域，CDS)区域 视频监控系统。VDS和CDS包含B细胞和T细胞表位，可诱导中和抗体和CD4+T细胞 负责保护性细胞免疫的反应。MOMP VDS对于每个血清型都是唯一的，如果 结合在一种疫苗中，可能会导致对所有分离株的广泛覆盖。一种基于MOMP的管理信息系统开发 然而，疫苗对人类的生产和使用构成了障碍。为了填补目前的空白，在我们之前的 R03 AI123885，我们设计了新型的重组嵌合抗原，插入了整个环2，3，5和6 将鼠疫杆菌MOMP转变为结构类似于MOMP的载体蛋白，即人类的PorB孔蛋白 共生内氏奈瑟菌。重组PorB/VD抗原适合于重组生产 折叠构象，具有免疫原性，诱导对重组MOMP、天然MOMP的交叉反应抗体 和整个Cm，对Cm呼吸道感染的小鼠有保护作用。我们的方法解决了 在不阻碍诱导功能性、保护性宿主免疫反应的情况下产生MOMP的缺点 敬衣原体。该假设是，等效的基于CT MOMP的结构，经过适当的调整，将诱导出 针对CT感染和疾病的保护性免疫反应，可以在小鼠模型中进行测试 经宫颈CT挑战。目的：1)设计、表达和纯化Ct MOMP血清型F型PorB/Vd1- 3、PorB/Vd1-4和PorB/Vd1-2-4，并检测重组载体的结构性质；2)确定 小鼠对PorB/VD载体的体液和细胞免疫应答 用于无反应性反应的人类和3)在小鼠中评估对Ct血清型F的保护 CT宫外孕模型的建立。我们的研究结果将填补一个严重的未满足的需求，以改善公众 并为研制具有广泛保护性的人体衣原体疫苗奠定基础。我们还将 定义由我们的疫苗诱导的与预防感染和疾病相关的免疫模式。

The overall goal of this project is to develop a vaccine against Chlamydia. Chlamydia trachomatis (Ct) is an obligate intracellular gram-negative organism and the most common cause of bacterial sexually transmitted infections (STIs) worldwide. Ct infections in women cause long-term sequelae i.e. pelvic inflammatory disease (PID), ectopic pregnancy and infertility, and are often associated with other STIs (HIV, HPV, gonorrhea and syphilis). Antibiotics do not prevent recurring infections. Development of a vaccine against Ct is a largely unmet need. Previous whole organisms-based vaccines only conferred limited protection from Ct ocular infections, with short-lived, serovar/subgroup-specific immunity and hypersensitivity reactions in some vaccinated individuals. The Chlamydia major outer membrane protein, MOMP, is a prime antigen candidate for a subunit vaccine. MOMP, a trimeric porin with 8 surface exposed loops, contains regions of sequence variability (variable domains, VDs) within loops 2, 3, 5 and 6 and regions of constant amino acid sequences (constant domains, CDs) flanking the VDs. The VDs and CDs contain B-cell and T-cell epitopes that elicit neutralizing antibodies and CD4+ T cell responses responsible for protective cellular immunity. The MOMP VDs are unique for each serovar and, if combined in a single vaccine, could induce broad coverage against all isolates. Development of a MOMP-based vaccine, however, presents barriers for production and use in humans. To fill the current gaps, in our previous R03 AI123885, we engineered novel recombinant chimeric antigens inserting the whole loops 2, 3, 5 and 6 of the C. muridarum (Cm) MOMP into a carrier protein structurally similar to MOMP, the PorB porin fromthe human commensal Neisseria lactamica. The recombinant PorB/VD antigens are suitable for recombinant production in a folded conformation, are immunogenic, induce cross-reactive antibodies to recombinant MOMP, native MOMP and whole Cm and are protective in a mouse model of Cm respiratory infection. Our approach addresses the shortcomings of MOMP production without hindering induction of functional, protective host immune responses to Chlamydia. The hypothesis is that equivalent Ct MOMP-based constructs, appropriately adjuvanted, will elicit protective immune responses against Ct infection and disease, which can be tested in a mouse model of transcervical Ct challenge. The Aims are 1) To design, express and purify Ct MOMP serovar F-based PorB/VD1- 3, PorB/VD1-4 and PorB/VD1-2-4 and examine structure properties of the recombinant constructs; 2) To define humoral and cellular immune responses to the PorB/VD constructs in mice using adjuvants that are suitable for use in humans without reactogenic responses and 3) To evaluate protection against Ct serovar F in the mouse model of Ct transcervical challenge. The results of our studies will fill a critical unmet need for improving public health worldwide and provide the groundwork for a broadly protective human Chlamydia vaccine. We will also define immune profiles induced by our vaccine that are associated with protection from infection and disease.