Identification of protective Lyme disease antigens using live attenuated vaccines

伯氏疏螺旋体、伯氏疏螺旋体B. garinii和B. afzelii是莱姆病在不同地理位置的所有代理人。如果 如果不治疗，莱姆病可导致严重和长期的发病率， 已给予适当的抗生素治疗，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。的 疫苗针对大量的B。伯氏表面脂蛋白，OspA，其由细菌产生 主要是当它们驻留在蜱虫和实验室培养物中时。这种疫苗可以防止感染， 血液抗OspA滴度足够高，但仅由单一OspA变体组成。最后， 该疫苗在大型三期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OspA序列的多样性，后来通过基因组 和ospA等位基因测序。在一些群体中也有人担心这种疫苗的安全性， 因为对OspA的反应性与莱姆关节炎有关，特别是治疗难治性关节炎，尽管 与对照组相比，接受疫苗的人关节炎没有增加。的 然而，莱姆病的发病率和地理传播的增加正在重新引起人们对接种莱姆病疫苗的兴趣。 风险人群，并通过最近对几个数据集的分析表明，莱姆病 美国的病例数实际上可能比报告给卫生部的病例数高出10倍。 CDC.我们采用了新的方法，用两种靶向的B突变株接种小鼠。布格多费里， 在小鼠中是无毒的。用两种菌株接种的小鼠可保护其免受亲本菌株的攻击 和异源B。通过针接种或蜱叮咬感染伯氏菌株。接种小鼠血清 也有保护性（被赋予“被动免疫”）。在蜱中，同源菌株被消除，但 异源菌株没有，这表明疫苗产生了针对抗原的应答， 在哺乳动物感染和蜱虫感染的早期由细菌产生。部分保护也是 对B不利。伽氏体感染。我们的假设是，减毒活疫苗株提供 识别新型保护性抗原的独特工具。为了进一步描述所产生的保护性反应， 针对减毒活疫苗，我们建议：1）鉴定被人血清识别的抗原， 2）生产和测试这些抗原的重组形式作为亚单位疫苗;和3） 分析免疫小鼠中的免疫应答，并评估与关节炎易感性的相关性， 用传染性B激发。burgdorferi。这些实验将检验新的假设，即减毒活B。 Burgdorferi菌株可以提供关于鉴定由细菌产生的保护性抗原的信息 并在体内被小鼠免疫系统识别。我们将采取的方法将阐明新的 这些候选抗原对于将来开发莱姆病疫苗是有效和安全的。

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.