Membrane-cloaked nanoparticles as mucosal vaccines against giardiasis

项目摘要 蓝氏贾第鞭毛虫是疾控中心B类原生动物的优先病原体，是引起腹泻疾病的重要原因 全球每年都有数以亿计的病例。在美国，兰布里亚革兰氏菌是两种最常见的 寄生虫病暴发的常见原因，患病率为1-7%。有症状的贾第鞭毛虫病是 以腹泻、上腹痛、恶心、呕吐、吸收不良和营养不良为特征，尤其是在 孩子们。长期的后遗症很常见，尽管治疗明显成功，但仍可能持续存在。 重要的是，感染可以通过摄入少于10个包囊而引发，这表明兰氏革兰氏菌是 高度传染性，对公共供水安全和健康构成可信的威胁。滋养体， 寄生虫的致病形式，寄生在小肠的管腔上并附着在上皮上。 感染通常是自我限制的，这表明存在有效的免疫防御。尽管临床上 由于蓝氏菌的重要性，目前尚无预防医学策略可用。先前的临床前研究表明 用个别表面抗原免疫可部分保护人体免受蓝氏菌感染。 老鼠和沙土鼠，但保护效果不如之前感染寄生虫，这表明单一的 抗原可能不足以诱导最佳保护。可以用活的进行多抗原免疫 病原体疫苗，但对革兰氏原虫尚未达到必要的减毒作用，可能也不会 可能是由于可预见的肠道定植能力受损所致。作为替代方案，我们提出一种 基于纳米颗粒的疫苗，由革兰氏杆菌菌株的膜构建，能够有效地 多抗原黏膜免疫，无需担心因活体微生物暴露而产生的不良反应。 由此产生的纳米颗粒疫苗提供了几个明显的优点：i)输送多种抗原性材料 存在于病原体表面，II)在体内有效转运的稳定性和均匀的大小和 有效地摄取抗原提呈细胞，以及iii)通过将核心加载到 适用于控制释放的佐剂。因此，我们的总体目标是开发蓝藻薄膜- 包被纳米颗粒作为预防贾第鞭毛虫病的一种新的粘膜疫苗策略。我们将系统地 用天然病原体膜制作不同的纳米疫苗配方并测试它们的 贾第鞭毛虫病相关动物模型的免疫原性和保护能力。这个项目带来了新的想法 以及从纳米技术领域到预防贾第鞭毛虫病的方法，这种高度传染性和 临床上重要但在很大程度上被忽视的腹泻病。重要的是，我们的创新战略克服了 识别单一保护性抗原或使用非天然、化学修饰的挑战 目标病原体的形式，从而极大地提高了对多个本地人的适应性免疫诱导 在活体寄生虫表面发现的蛋白质。这一新策略对疫苗设计具有广泛的影响 其他粘膜病原体，不仅包括原生动物，还包括细菌和病毒。

Project Summary Giardia lamblia, a protozoan CDC category B priority pathogen, is an important cause of diarrheal disease with hundreds of millions of annual cases worldwide. In the United States, G. lamblia is one of the two most common causes of outbreaks of parasitic disease, with prevalence rates of 1-7%. Symptomatic giardiasis is characterized by diarrhea, epigastric pain, nausea, vomiting, malabsorption and malnutrition, especially in children. Long-term sequelae are common and can persist despite apparently successful treatment. Importantly, infection can be initiated by ingestion of fewer than ten cysts, demonstrating that G. lamblia is highly contagious and a credible threat to the safety of public water supplies and health. Trophozoites, the disease-causing forms of the parasite, colonize the lumen of the small intestine and attach to the epithelium. Infection is typically self-limiting, indicating that effective immune defenses exist. Despite the clinical importance of G. lamblia, no preventive medical strategies are available. Prior preclinical studies have shown that immunization with individual surface antigens can confer partial protection against G. lamblia infection in mice and gerbils, but protection is not as effective as prior infection with the parasite, suggesting that single antigens may not be sufficient to induce optimal protection. Multi-antigen immunizations can be done with live pathogen vaccines, but the necessary attenuation has not been achieved for G. lamblia and may not be possible due to the predictably compromised ability to colonize the intestine. As an alternative, we propose a nanoparticle-based vaccine, constructed from the membranes of G. lamblia strains, which enables effective multi-antigen mucosal immunization without concerns about adverse effects due to live microbe exposure. The resulting nanoparticle vaccines offer several distinct advantages: i) delivery of multi-antigenic material present on the pathogen surface, ii) stability and homogeneous sizing for effective transport in vivo and efficient uptake into antigen-presenting cells, and iii) tunable immunological biasing by loading the core with suitable adjuvants for controlled release. Therefore, our overall objective is to develop G. lamblia membrane- coated nanoparticles as a novel mucosal vaccination strategy against giardiasis. We will systematically fabricate different nanovaccine formulations with native pathogen membranes and test them for immunogenicity and protective capacity in relevant animal models of giardiasis. This project brings new ideas and approaches from the field of nanotechnology to the prevention of giardiasis, a highly contagious and clinically important but largely neglected diarrheal disease. Importantly, our innovative strategy overcomes the challenges associated with identifying single protective antigens or with using non-native, chemically modified forms of the target pathogen, thereby greatly improving induction of adaptive immunity to multiple native proteins found on the live parasite surface. The new strategy has broad implications for vaccine design for other mucosal pathogens, including not only protozoan, but also bacterial and viral agents.