One Health Vaccine Development for Bovine and Human Schistosomiasis

这项One Health申请的总体目标是加速副肌球蛋白（rSj97）和一种新发现的抗原（rSj68）作为人类和牛血吸虫病疫苗的开发。血吸虫病由三种主要的雌雄异株吸虫（扁虫）引起，目前感染人数超过2.5亿人，每年损失153万残疾调整生命年1，并造成流行地区健康状况不佳和经济停滞2。尽管吡喹酮（PZQ）可以有效治疗血吸虫病，但快速再感染和反弹发病率阻碍了仅基于化疗的有效控制，这证明了目前开发这些寄生虫疫苗的努力是合理的。最重要的是，日本血吸虫是一种人畜共患病，驯养的水牛（水稻种植的主要劳动力）患有该疾病，并且构成继续传播给人类的关键水库。在我们最近的工作中，我们发现居住在菲律宾Leyte的水牛的感染率为97%-强调了这些物种传播给人类的重要性。副肌球蛋白最初被确定为在接种曼氏血吸虫或成虫提取物3的小鼠中产生的抗体的寄生虫靶点。本课题组对日本血吸虫4号株的副肌球蛋白及其保护作用进行了关键性研究。在四个独立的实验中，用生化纯化的副肌球蛋白（Sj97）接种小鼠后，子宫颈攻击后蠕虫负荷减少62%-86%（均P < 0.001）。我们在616名日本血吸虫感染者治疗-再感染队列中对Sj97进行了广泛的免疫流行病学研究5。我们发现，在Sj97刺激的PBMCs中测量的Th2/Th1细胞因子比率较高的个体，吡喹酮治疗后，再感染强度降低了30%至41%（均P < 0.05）。在同一队列中，我们最近证明，即使在调整潜在混杂因素（p=0.016）后，对rSj97有IgE而非IgG4反应的个体在12个月时的再感染强度比有IgG4而非IgE反应的个体低77%。我们使用一种新的鉴别筛选方法鉴定了rSj68，这种方法可以识别由耐药而非易感儿童表达的抗体识别的寄生虫抗原7。通过免疫荧光和免疫金电镜观察，发现rSj68定位于成虫的被皮和胃真皮层。在菲律宾的一个全流行地区，与没有这些抗体的个体相比，具有高滴度IgE抗rsj68的个体在12个月的随访中再感染强度降低了58% （n=616, P < 0.001）。在目前的申请中，我们建议通过在水牛中进行安全性和有效性试验，加快副肌球蛋白和rSj68作为人血吸虫病和牛血吸虫病疫苗的开发。我们将把研究重点放在已经在人类和动物身上测试并发现安全的佐剂上，从而加快我们在人类和牛身上进行I期疫苗接种研究和II期研究的开发工作。该项目的交付成果将是一种佐剂优化的二价血吸虫疫苗，该疫苗已准备好进行人体I期和牛II期试验，其安全性数据将支持FDA IND申请。这种疫苗将对“同一个健康”的目标产生巨大影响，包括：1)改善动物健康，2)提高动物生产力，3)提高农场产量，4)减少血吸虫病向人类的传播，以及5)由于直接（人类疫苗接种）和间接（水牛疫苗接种）的影响而改善人类健康。

The overall aim of this One Health application is to accelerate the development of paramyosin (rSj97) and a newly discovered antigen (rSj68) as vaccines against human and bovine schistosomiasis japonica. Schistosomiasis, caused by three principle species of dioecious trematodes (flatworms), currently infects over 250 million individuals, results in 1.53 million DALYs lost per annum 1, and contributes to poor health and economic stagnation in endemic areas 2. Although schistosomiasis is effectively treated with praziquantel (PZQ), rapid reinfection with rebound morbidity precludes effective control based on chemotherapy alone and justifies current efforts to develop vaccines for these parasites. Most importantly, Schistosoma japonicum is a zoonosis with domesticated water buffalo (the key labor force for rice farming) suffering from the disease, as well as constituting a critical reservoir for continuing transmission to humans. In our recent work, we show that buffalo residing in our field site in Leyte, the Philippines have a prevalence of infection of 97%- underscoring the importance of these species for transmission to humans. Paramyosin was originally identified as the parasite target of antibodies generated in mice protectively vaccinated with S. mansoni schistosomula or adult worm extract 3. Our group conducted the pivotal study linking paramyosin and protection in S. japonicum 4. In four independent experiments, vaccination of mice with biochemically purified paramyosin (Sj97) resulted in 62%-86% (all P < 0.001) reduction in worm burden following cercarial challenge. We have conducted extensive immuno-epidemiology studies of Sj97 in a treatment-reinfection cohort of 616 S. japonicum infected individuals 5. We demonstrate a 30 to 41% lower intensity of reinfection (all P < 0.05) after praziquantel treatment in individuals with high Th2/Th1 cytokine ratios measured in PBMCs stimulated with Sj97. In this same cohort, we recently demonstrated that individuals with IgE but not IgG4 responses to rSj97 had a 77% lower intensity of reinfection at 12 months compared to individuals with IgG4 but not IgE responses, even after adjusting for potential confounders (p=0.016) 6. We identified rSj68 using a novel differential screening approach to identify parasite antigens recognized by antibodies expressed by resistant, but not susceptible children 7. By immunofluorescence and immunogold electron microscopy, rSj68 localizes to the tegument and gastro-dermis of adult male and female worms. In a holoendemic site in the Philippines, individuals with high titer IgE anti-rSj68 had a 58% lower intensity of reinfection over 12 months of follow-up compared to individuals without these antibodies (n=616, P < 0.001). In the current application, we propose to accelerate the development of paramyosin and rSj68 as vaccines for human and bovine schistosomiasis by conducting safety and efficacy trials in water buffaloes. We will focus our studies on adjuvants that have already been tested and found safe in humans and animals, thus accelerating our development efforts toward a Phase I vaccination study in humans and Phase II studies in bovines. The deliverables of this program will be an adjuvant optimized, bivalent schistosome vaccine that is ready for human Phase I and bovine Phase II trials with safety data to support an FDA IND application. This vaccine would have a tremendous impact on One Health objectives, including: 1) improved animal health, 2) improved animal productivity, 3) improved farm output, 4) decreased transmission of schistsosomaisis to humans, and 5) improved human health due to both direct (human vaccination) and indirect (buffalo vaccination) effects.