Identification of protective Lyme disease antigens using live attenuated vaccines

伯氏疏螺旋体、加里氏疏螺旋体和弗氏疏螺旋体都是不同地理位置的莱姆病病原。如果 如果不进行治疗，莱姆病可能会导致显著的长期发病率，这种情况可能会在 已经实施了适当的抗生素治疗，不再检测到活细菌。有一个 1998年至2002年，莱姆病疫苗可供人类使用，但该疫苗已不再可用。这个 疫苗针对的是由细菌产生的丰富的伯氏杆菌表面脂蛋白OspA 主要是当它们寄生在扁虱和实验室培养物中时。这种疫苗在以下情况下可防止感染 血流抗OspA效价足够高，但只有一种OspA变体。最终， 该疫苗在大型第三阶段试验和随后的上市后提供了约80%的有效保护 监测，可能至少部分是由于后来由基因组揭示的OspA序列的多样性 OspA等位基因测序。一些群体还对这种疫苗的安全性表示担忧， AS对OspA的反应性与莱姆关节炎，特别是治疗难治性关节炎有关，尽管 与对照组相比，接种疫苗的人类关节炎没有增加。这个 然而，莱姆病发病率的增加和地理传播重新引起了人们对接种莱姆病疫苗的兴趣。 高危人群，最近对几个数据集的分析表明莱姆病 美国的病例数量实际上可能比美国政府报告的病例数量高出十倍。 疾控中心。我们采取了一种新的方法，用两个有针对性的伯氏杆菌突变株接种小鼠 在小鼠身上是无毒的。接种两种毒株的小鼠都能抵抗亲本毒株的攻击。 以及一株异源伯氏杆菌菌株，通过针头接种或扁虱叮咬。接种疫苗小鼠的血清 也是保护性的(被授予“被动免疫”)。在扁虱中，同源菌株被消除，但 异源菌株不是，这表明疫苗对 由这种细菌在哺乳动物感染早期和扁虱体内产生。部分保护也是 被授予对抗加里尼氏杆菌感染的权利。我们的假设是，减毒活疫苗株提供了 识别新的保护性抗原的独特工具。为了进一步描述引起的保护性反应 针对减毒活疫苗，我们建议1)识别能被猪瘟病毒血清识别的抗原。 免疫小鼠；2)生产和测试这些抗原的重组版本作为亚单位疫苗；以及3) 分析免疫小鼠的免疫反应，并评估与关节炎易感性的关系 对传染性伯氏杆菌的挑战。这些实验将检验这一新的假设，即活的衰减B。 伯氏杆菌菌株可以为细菌产生的保护性抗原的鉴定提供信息。 并被体内的小鼠免疫系统识别。我们将采取的方法将照亮新的 对莱姆病疫苗的未来开发是有效和安全的候选抗原。

Borrelia burgdorferi, B. garinii and B. afzelii are all agents of Lyme disease in different geographic locations. If left untreated, Lyme disease can cause significant and long-term morbidity, which may continue after appropriate antibiotic therapy has been administered and live bacteria are no longer detectable. There was a Lyme disease vaccine available for human use from 1998 to 2002, but that vaccine is no longer available. The vaccine targeted an abundant B. burgdorferi surface lipoprotein, OspA, which is produced by the bacteria primarily while they reside in the tick and in laboratory culture. This vaccine protected against infection when bloodstream anti-OspA titer was sufficiently high, but was comprised of only a single OspA variant. Ultimately, this vaccine afforded ~80% effective protection in the large phase three trial and in subsequent post-market monitoring, likely at least in part due to the diversity of OspA sequences that was later revealed by genome and ospA allele sequencing. There was also concern regarding the safety of this vaccine among some groups, as reactivity to OspA was associated with Lyme arthritis, particularly the treatment-refractory arthritis, although no increase in arthritis was seen in humans who received the vaccine compared to control groups. The increasing incidence and geographic spread of Lyme disease, however, is renewing interest in vaccination of at-risk populations, and is fueled by recent analyses of several data sets that indicate that the Lyme disease case numbers in the USA may actually be up to ten times higher than the number of cases reported to the CDC. We took the novel approach of vaccinating mice with two targeted mutant strains of B. burgdorferi that are avirulent in mice. Mice vaccinated with both strains were protected against challenge by the parental strain and a heterologous B. burgdorferi strain by either needle inoculation or tick bite. Sera from vaccinated mice were also protective (conferred “passive immunity”). In ticks, the homologous strain was eliminated but the heterologous strain was not, suggesting that the vaccines generated a response against antigens that are produced by the bacteria both early in mammalian infection and in the tick. Partial protection was also conferred against B. garinii infection. Our hypothesis is that the live attenuated vaccine strains provide unique tools to identify novel protective antigens. To further characterize the protective response raised against the live attenuated vaccines, we propose to 1) Identify antigens that are recognized by the sera of vaccinated mice; 2) Produce and test recombinant versions of these antigens as subunit vaccines; and 3) Analyze the immune response in immunized mice and evaluate association with susceptibility to arthritis upon challenge with infectious B. burgdorferi. These experiments will test the novel hypothesis that live attenuated B. burgdorferi strains can be informative regarding identification of protective antigens produced by the bacteria and recognized by the mouse immune system in vivo. The approaches we will take will illuminate new candidate antigens that are effective and safe for future development of Lyme disease vaccines.