POLLEN GRAINS AS TROJAN HORSES FOR ORAL VACCINATION

描述（由申请人提供） 翻译后摘要：我们建议将花粉粒转化为一个强大的和广泛适用的口服疫苗接种平台。口服疫苗递送一直是疫苗接种领域的长期目标，因为它是无针的，可以自我施用，并且可以产生全身和粘膜免疫应答。粘膜免疫是粘膜表面的一种强大的宿主调节防御，可以在病原体仍在人体外时中和它们，然后才能引起感染。胃肠道粘膜像其他粘膜表面一样遭受微生物的持续侵袭，并形成病原体进入的主要门户。因此，能够刺激胃肠道粘膜的粘膜免疫将为人类提供巨大的免疫优势，以帮助抵御微生物入侵。继续阻碍成功口服疫苗接种的主要障碍是疫苗在胃中的降解及其在肠上皮细胞衬里中的吸收不良。花粉 谷物是一种天然的工程奇迹，具有解决这些障碍的潜力。花粉粒具有非常坚韧的外壳，可以承受胃的酸性和酶环境，并且它们可以作为完整的颗粒穿过胃肠道粘膜的紧密上皮细胞进入体内。我们建议利用这些奇妙的天然颗粒，并将它们转化为特洛伊木马，以安全地将疫苗抗原穿过胃的恶劣环境，穿过紧密的上皮屏障，进入体内。我们已经通过给小鼠喂食充满卵清蛋白的花粉粒作为模型抗原来测试我们看似奇特的想法的可行性。接种后小鼠血清中产生抗卵清蛋白免疫球蛋白G（IgG）抗体。重要的是，发现花粉粒诱导的抗卵清蛋白IgG水平比使用霍乱毒素（CT）作为阳性对照诱导的抗卵清蛋白IgG水平高10倍以上。这一结果是非常重要的，因为CT作为粘膜佐剂是目前口服疫苗接种的金标准，我们的数据表明花粉粒上级CT。我们对这一发现感到非常兴奋，我们建议通过多学科方法，将生物工程、药物输送和疫苗学的基础知识联系起来，进一步开发这种有前途的口服疫苗接种策略。我们的两个互补的目标，将移动这种方法更接近人体试验是：（i）表征花粉粒，并制定一个机械的理解，他们的特洛伊木马 能力，和（ii）了解粘膜和全身免疫反应产生的花粉粒为基础的口服疫苗接种，并探讨免疫调节的协同使用佐剂的潜力。总的来说，这种基于花粉粒的口服疫苗递送平台预计是高度通用的，因此具有开发针对许多传染病的粘膜疫苗的潜力。 公共卫生相关性：该项目旨在开发一种新的口服疫苗接种方法，该方法无痛，对儿童友好，更安全，功能上级现有的使用皮下注射针的肌肉注射疫苗接种途径。这种运送方法将具有广泛的适用性，能够运送多种疫苗。

DESCRIPTION (Provided by the applicant) Abstract: We propose to transform pollen grains into a powerful and broadly applicable oral vaccination platform. Oral vaccine delivery has been a longstanding goal in the field of vaccination because it is needle-free, can be selfadministered and can produce both systemic and mucosal immune responses. Mucosal immunity is a powerful host-regulated defense at the mucosal surfaces that can neutralize pathogens while they are still outside the human body, before they can cause infection. The gastrointestinal mucosa like other mucosal surfaces suffers from constant onslaughts of microbes and forms a major portal of pathogen entry. Therefore, being able to stimulate mucosal immunity at the gastrointestinal mucosa will offer a tremendous immunological advantage to humans to help fight-off microbial invasions. The major roadblocks that continue to obstruct successful oral vaccination are the degradation of vaccines in the stomach and their poor uptake across the intestinal epithelial cell lining. Pollen grains are a natural engineering marvel with potential to address these roadblocks. Pollen grains have very tough exterior shells, which can withstand the acidic and enzymatic environment of the stomach and they can pass in to the body as intact particles across the tight epithelial cells of the gastrointestinal mucosa. We propose to exploit these fantastic natural particles and transform them into ¿Trojan horses¿ to safely ferry vaccine antigens across the harsh environment of the stomach and across the tight epithelial barrier, into the body. We have tested the feasibility of our seemingly peculiar idea by feeding mice with pollen grains filled with ovalbumin as a model antigen. Anti-ovalbumin immunoglobulin G (IgG) antibodies were produced in mouse serum after the vaccination. Importantly, the anti-ovalbumin IgG levels induced by pollen grains were found to be more than ten-fold higher than the anti-ovalbumin IgG levels induced by the use of cholera toxin (CT) as a positive control. This result is very significant because CT as a mucosal adjuvant is the current gold standard for oral vaccination and our data suggests that pollen grains are superior to CT. We are very excited by this discovery and we propose to further develop this promising strategy for oral vaccination through a multidisciplinary approach bridging the fundamentals of bioengineering, drug delivery and vaccinology. Our two complementary goals that will move this approach closer to human trials are: (i) characterize pollen grains and develop a mechanistic understanding of their Trojan ability, and (ii) understand mucosal and systemic immune responses generated by pollen grain-based oral vaccination and explore the potential of immunomodulation by the synergistic use of adjuvants. Overall, this pollen grain-based oral vaccine delivery platform is expected to be highly versatile and thus has potential to be harnessed for development of mucosal vaccines against a host of infectious diseases. Public Health Relevance: This project seeks to develop a novel methodology for oral vaccination, which is painless, child-friendly, safer and functionally superior to the exiting intramuscular route of vaccination using hypodermic needles. The delivery methodology will have broad applicability and will be able to deliver a broad range of vaccines.