MICA VACCINE FAPESP MICA: Pulmonary Delivery of a Targeted Mucosal Nanocarrier Vaccine for Pneumonia

肺炎链球菌是一种细菌，它利用肺部作为进入人体的途径，引起社区获得性肺炎（CAP）。它是全世界儿童、老年人和免疫功能低下者健康不良和死亡的主要原因。此外，在成年人中，它是CAP的主要原因，随着预期寿命的增加和对抗生素的耐药性的增加，CAP可能会上升。此外，如果S.肺炎如果不治疗，它会进入血液，导致危及生命的败血症和脑膜炎。与肺炎球菌感染相关的卫生服务费用为10亿英镑（英国），55亿美元（美国），100亿欧元（欧洲）和2.4亿美元（巴西）。世界卫生组织将疫苗接种视为对抗传染病的重要公共卫生策略。疫苗应安全、有效、实用和负担得起。目前的疫苗只能提供对13种最常见的沙门氏菌的保护。肺炎，并且对CAP的有效性有限。为了有效，需要多种候选疫苗提供针对许多不同菌株的交叉保护。然而，这是不切实际的，因为成本高，生产时间长。此外，它是通过注射给药，导致肺内的免疫保护差。因此，需要一种更有效的候选疫苗，其可以安全地和实际上直接给予肺部，从而提供更好的抗链球菌保护。通过肺接种疫苗是一种有吸引力的途径，因为它模拟了肺炎链球菌的天然感染途径。肺炎，并可通过其他连接部位（如鼻和肠）对全身产生免疫保护。吸入的优点是消除了注射器和针头，消除了安全处置的危险，降低了血液传播感染的风险。被称为抗原的细菌的各个部分可以刺激免疫反应。巴西布坦坦研究所的研究人员提出了所有菌株都共有的蛋白质：PspA，来自S。pneumoniae，遗传脱毒肺炎球菌溶血素（PdT）和PspA-PdT融合蛋白。这三种蛋白质将分别掺入小颗粒（纳米颗粒，NP）中，并在活性，免疫反应和雾化效率方面相互比较。NP是安全的，并且具有有助于激活免疫应答的佐剂性质，因此可以使用较低的蛋白质浓度产生更强的免疫应答。此外，由于纳米颗粒的尺寸（~ 200 nm），它们可以穿过肺中的屏障，并促进抗原呈递细胞对蛋白质的摄取，抗原呈递细胞可以有效地启动肺中的免疫应答。为了增加纳米颗粒向肺中的递送，将它们包埋在使用药学惰性氨基酸或糖制备的较大微粒载体中，从而得到适合于在肺内沉积的粒度（1- 5微米）的干粉纳米复合微粒载体（NCMP）。此外，我们亦会以雾化方式测试非吸烟颗粒剂，这对使用传统干粉吸入器有困难的儿童及长者有帮助。本项目将评估NPs/NCMP作为PspA或PdT或PspA-PdT载体的疫苗递送，通过吸入增强小鼠的免疫应答，与作为对照的游离抗原的针接种相比，用于预防肺炎球菌疾病。我们将研究通过该途径单次和加强注射后的免疫应答，并评估对S。肺炎在肺部的挑战。如果成功，我们的疫苗纳米载体技术平台不仅可以应用于人类健康，还可以用于兽医用途。

Streptococcus pneumoniae is a bacterium that uses the lungs as a route of entry into the body causing community acquired-pneumonia (CAP). It is a leading cause of ill-health and death in children, elderly and immunocompromised worldwide. Moreover, amongst adults, it is the leading cause of CAP which is likely to rise with increasing life expectancy and escalating resistance towards antibiotics. Furthermore, if S. pneumoniae is not treated it can gain entry into the blood resulting in life-threatening septicaemia and meningitis. The health service costs associated with pneumococcal infection is £1 billion (UK), $5.5 billion (USA), 10 billion Euros (Europe) and $240 million (Brazil). The World Health Organization regards vaccination as an important public health strategy to combat infectious diseases. Vaccines should be safe, effective, practical and affordable. The current vaccine only offers protection against 13 most common strains of S. pneumoniae and has limited effectiveness against CAP. To be effective multiple vaccine candidates are required offering cross-protection against the many different strains. However, this is not practical due to high costs and lengthy timescale for production. Furthermore, it is administered via injection resulting in poor immune protection within the lungs. Therefore, there is a need for a more effective vaccine candidate that can be given safely and practically directly to the lungs providing better protection against S. pneumoniae.Vaccination via the lungs is an attractive avenue as it mimics the natural infection route of S. pneumoniae and can lead to immune protection over the whole body via other connected sites, such as nose and intestines. Inhalation offers the advantage of eliminating syringes and needles, removing the hazard of safe disposal and lowering the risk of blood-borne infections. Various parts of bacteria known as antigens can stimulate an immune response. Researchers in Institute Butantan, Brazil are proposing proteins common to all strains: PspA, from the surface of S. pneumoniae, genetically detoxified pneumolysin (PdT) and PspA-PdT fusion protein. The three proteins will be separately incorporated into small particles (nanoparticles, NPs) and compared to each other with regards to activity, immune response and aerosolisation efficiency into the lungs. The NPs are safe and have adjuvant properties which help activate an immune response, hence can result in a stronger immune response using lower protein concentrations. Moreover, due to the NPs size (~200nm) they can cross barriers in the lungs and promote the uptake of proteins by antigen presenting cells that can effectively initiate an immune response in the lungs.In order to increase delivery of NPs into the lungs, they are embedded within larger microparticle carriers prepared using pharmaceutically inert amino-acids or sugars, resulting in dry powder nanocomposite microparticle carriers (NCMPs) of suitable particle size (1-5micron) for deposition within the lung. In addition, we will also test the NCMPs via nebulisation, which is of benefit to children and elderly who have difficulty with using conventional dry powder inhalers. Furthermore, the formation of dry powder NCMPs will increase the stability of NPs and antigen, and eliminate cold temperature transport and storage.This project will evaluate vaccine delivery of NPs/NCMPs as carriers of PspA or PdT or PspA-PdT, for the prevention of pneumococcal diseases via inhalation enhancing immune response in mice compared to needle-based vaccination of free antigen as control. We will investigate the immune responses after single and booster injections through this route, and evaluate the protection against S. pneumoniae challenge in the lungs. If successful, our vaccine nanocarrier technology platform can be applied to a range of different infectious agents not only in human health but also for veterinary use.