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

肺炎链球菌是一种利用肺部作为进入人体的途径，导致社区获得性肺炎(CAP)的细菌。它是导致世界各地儿童、老年人和免疫功能受损的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，随着预期寿命的延长和对抗生素耐药性的增加，CAP可能会上升。此外，如果不对肺炎链球菌进行治疗，它可能会进入血液，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分别为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)。世界卫生组织将接种疫苗视为抗击传染病的重要公共卫生战略。疫苗应该是安全、有效、实用和负担得起的。目前的疫苗只对13种最常见的肺炎链球菌提供保护，对CAP的效果有限。为了有效，需要多个候选疫苗提供对许多不同毒株的交叉保护。然而，这是不切实际的，因为生产成本高，生产时间长。此外，它是通过注射给药的，导致肺部免疫保护较差。因此，需要一种更有效的候选疫苗，可以安全和实际地直接接种到肺部，提供更好的预防肺炎链球菌的保护。通过肺部接种疫苗是一种有吸引力的途径，因为它模仿肺炎链球菌的自然感染途径，并可以通过其他相连的部位，如鼻子和肠道，对全身产生免疫保护。吸入的好处是消除了注射器和针头，消除了安全处置的危险，并降低了血液传播感染的风险。被称为抗原的细菌的不同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共有的蛋白质：来自肺炎链球菌表面的PSPA，基因解毒的肺炎溶血素(PDT)和PSPA-PDT融合蛋白。这三种蛋白质将被分别加入到小颗粒(纳米颗粒，NPs)中，并在活性、免疫反应和进入肺部的气雾化效率方面相互比较。这些NPs是安全的，具有佐剂特性，有助于激活免疫反应，因此可以用较低的蛋白质浓度产生更强的免疫反应。此外，由于NPs的大小(~200 nm)可以跨越肺内的屏障，促进抗原提呈细胞摄取蛋白质，从而有效地启动肺部的免疫反应。为了增加NPs进入肺部的输送，它们被嵌入使用药物惰性氨基酸或糖制备的更大的微粒载体中，从而形成适合微粒尺寸(1-5微米)的干粉纳米复合微粒载体(NCMMP)，用于在肺内沉积。此外，我们亦会以雾化方式测试非中药成分，这对使用传统干粉吸入器有困难的儿童和长者是有好处的。此外，干粉NCMMPs的形成将增加NPs和抗原的稳定性，并消除低温运输和储存。本项目将评估NPs/NCMMPs作为PSPA或PDT或PSPA-PDT的载体，通过吸入增强小鼠的免疫反应来预防肺炎球菌疾病的疫苗输送，并与以游离抗原为对照的针头接种进行比较。我们将通过这一途径研究单次注射和加强注射后的免疫反应，并评估对肺炎链球菌在肺部攻击的保护作用。如果成功，我们的疫苗纳米载体技术平台不仅可以应用于一系列不同的感染源，不仅可以用于人类健康，还可以用于兽医。

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.