A parainfluenza virus 5 (PIV5)-based bivalent vaccine for respiratory syncytial virus (RSV) and human metapneumovirus (HMPV)

摘要 在R21的应用中，我们建议开发一种基于鼻腔副流感病毒5(PIV5)的通用病毒 呼吸道合胞病毒(RSV)和人偏肺病毒(HMPV)双价疫苗。RSV和HMPV是 儿童急性呼吸道感染(ARI)的两个主要原因是免疫功能低下的人， 还有老年人。疾病范围从无症状感染到严重的毛细支气管炎和肺炎，90%-100% 2岁前感染呼吸道合胞病毒，5-10岁感染HMPV。无许可证 RSV或HMPV疫苗已可用，开发安全有效的疫苗的医学需求尚未得到满足 对这两种疾病都有效。最近的一项原理验证研究表明，创造嵌合的F蛋白是可能的 (RHMS-1)通过结合RSV F和HMPV F的免疫优势表位，保持两者的抗原性 纯化的蛋白具有免疫原性，对RSV和HMPV的攻击具有免疫保护作用。然而， 这种纯化的蛋白质需要佐剂和多剂量的方法，细胞介导的免疫反应是 没有研究，抗体应答的持续时间还没有确定，存在潜在的安全性 由于疫苗具有免疫原性所需的高剂量蛋白质，儿童受到了关注。PIV5是一个保险箱 鼻腔免疫的递送载体。一种PIV5载体RSV候选疫苗(BLB-201)已经被 被FDA批准进行今年的I期临床试验(NCT05281263)。由于RSV和RSV之间的相似性 HMPV F蛋白、疾病表现和目标人群，需要双价疫苗来预防 由两种病毒引起的ARI疾病。在这里，我们建议将RHMS-1新序列引入PIV5- 矢量化疫苗平台。我们还将对RHMS-1序列进行修改，以改进F蛋白 目的基因的表达及其免疫原性。待评估的构建物包括：1)RHMS-1融合前；和2) RHMS-1的三聚结构域被跨膜区和细胞质取代的预融合形式 尾巴来自PIV5 F蛋白。将对候选疫苗病毒的复制和抗原进行比较 呼吸道合胞病毒和人乳头状瘤病毒攻击感染的体外表达、免疫原性和保护性研究 活着。R21申请中提出的疫苗的新颖性涉及：1)使用嵌合RSV+HMPV 针对两种病原体的F蛋白(双价疫苗)；2)一种安全、高度安全的无针鼻内给药方法 免疫原性病毒载体；3)易于给药；4)诱导细胞和抗体反应的能力 包括黏膜免疫，这是抵御呼吸道病原体所必需的。这个项目是非常 有希望制造出一种有效的双价疫苗，可以提供对两种主要原因的保护 儿童和老年人的急性下呼吸道感染。

ABSTRACT In this R21 application, we propose to develop a universal, intranasal, parainfluenza virus 5 (PIV5)-based respiratory syncytial virus (RSV) and human metapneumovirus (HMPV) bivalent vaccine. RSV and HMPV are two of the leading causes of acute respiratory infections (ARIs) in children, immunocompromised individuals, and the elderly. Illness ranges from asymptomatic infection to severe bronchiolitis and pneumonia, with 90-100% of children infected with RSV by 2 years of age, and HMPV between the ages of 5-10 years old. No licensed RSV or HMPV vaccine is available and there is an unmet medical need to develop safe and effective vaccines for both diseases. A recent proof-of-principle study has shown that it is possible to create a chimeric F protein (RHMS-1) by combining immunodominant epitopes from RSV F and HMPV F that retains antigenicity for both viruses, the purified protein is immunogenic and protective against RSV and HMPV challenge in mice. However, this purified protein requires an adjuvant and a multi-dose approach, the cell-mediated immune response was not studied, the duration of the antibody response has not been determined, and there is a potential safety concern for children due to the high dose of protein required for the vaccine to be immunogenic. PIV5 is a safe delivery vector for intranasal immunization. A PIV5-vectored RSV candidate vaccine (BLB-201) has already been cleared by the FDA for a phase I clinical trial this year (NCT05281263). Due to the similarities between RSV and HMPV F proteins, disease manifestation, and target populations, a bivalent vaccine is desirable to protect against ARI diseases caused by both viruses. Here, we propose to introduce the RHMS-1 novel sequence into the PIV5- vectored vaccine platform. We will also make a modification to the RHMS-1 sequence to improve F protein expression and its immunogenicity. The constructs to be evaluated include: 1) RHMS-1 pre-fusion; and 2) RHMS-1 pre-fusion form with the trimerization domain replaced with the transmembrane domain and cytoplasmic tail from the PIV5 F protein. The candidate vaccine viruses will be compared for their replication and antigen expression in vitro, and immunogenicity and protective efficacy against RSV and HMPV challenge infection in vivo. The novelty of the vaccine proposed in this R21 application relates to: 1) the use of a chimeric RSV+HMPV F protein against two pathogens (bivalent vaccine); 2) a needle-free intranasal delivery method in a safe, highly immunogenic viral vector; 3) ease of administration; and 4) the ability to induce cellular and antibody responses including mucosal immunity, which is necessary for protecting against respiratory pathogens. The project is very promising in generating an effective bivalent vaccine that could provide protection against the two leading causes of acute lower respiratory tract infections in children and older adults.