Human Coronaviruses as Multigene Mucosal Vaccine Vectors for HIV

描述(申请人提供)：一种有效的HIV-1疫苗方法不仅需要在全身和粘膜部位诱导广泛反应的中和抗体和细胞免疫反应，而且疫苗还必须具有可行性，才能分发到世界上最需要它的地区，包括安全性、制造成本、接种次数和管理简易性。人类普通感冒冠状病毒(HCoV)OC43作为人类免疫缺陷病毒(HIV)的疫苗载体很有吸引力，最近冠状病毒反向遗传学的突破使其作为疫苗载体的开发成为可能。冠状病毒基因组是自然界中最大的RNA基因组(~30kb)，包含多个对病毒复制不必要的基因，理论上允许将多个异源基因插入到单个病毒中，其包装容量比大多数其他载体系统大得多。由于HCoV OC43只会引起轻微的上呼吸道感染，因此作为疫苗载体预计是相对安全的，允许复制能力强的病毒将异种抗原呈现在粘膜表面进行多轮载体复制，就像减毒活疫苗一样。还可以对冠状病毒基因组进行改造，使其与自然传播的毒株重组产生死亡病毒。我们最近完成了HCoV OC43反向遗传学系统的开发，这使得开发基于HCoV OC43的疫苗载体在技术上是可行的。在这个阶段性创新R21/R33项目中，我们建议将HCoV OC43基因组设计为SIV的多个异源基因表达载体，我们将使用SIVsmE660/Macaque模型进行评估。在R21概念验证阶段，我们将：(I)工程HCoV OC43表达来自载体基因组不同区域的SIVsmH4基质/衣壳(MA/CA)基因，以及(Ii)评估表达MA/CA的HCoV OC43载体的系统、粘膜和细胞免疫原性。在R33阶段，我们将：(I)鉴定HCoV OC43在猕猴中的感染性，(Ii)设计并验证抗重组HCoV OC43构建体，以表达多达四种SIVsmH4蛋白-Gag、Env、Nef和Vif，以及(Iii)用多基因HCoV OC43载体接种猕猴，并通过SIVsm E660粘膜攻击来评估疫苗效果。该项目将首次对普通感冒人类冠状病毒作为艾滋病毒活粘膜疫苗载体的潜在用途进行关键评估。公共卫生相关性：在拟议的研究中，我们将开发人类冠状病毒作为疫苗载体来传递艾滋病毒抗原。人类冠状病毒是导致大约三分之一的常见感冒的原因。冠状病毒载体作为HIV疫苗有几个潜在的吸引人的特点，如安全性、制造简单、在HIV传播点诱导免疫反应的能力以及通过有限数量的接种诱导免疫反应的能力。我们将使用SIV/猕猴模型评估冠状病毒作为HIV疫苗载体的潜在用途。

DESCRIPTION (provided by applicant): An effective HIV-1 vaccine approach not only will need to induce broadly reactive neutralizing antibody and cellular immune responses at systemic and mucosal sites, but the vaccine also will have to be feasible for distribution to parts of the world that need it most in terms of safety, manufacturing cost, number of inoculations, and ease of administration. The common cold human coronavirus (HCoV) OC43 is attractive as a vaccine vector for HIV, and recent breakthroughs in coronavirus reverse genetics have now made it feasible for their exploitation as vaccine vectors. Coronavirus genomes are the largest RNA genomes in nature (~30kb), and contain multiple genes that are not essential for viral replication, theoretically allowing the insertion of multiple heterologous genes into a single virus with a packaging capacity much larger than most other vector systems. Because HCoV OC43 causes only a mild upper respiratory tract infection, it is anticipated to be relatively safe as a vaccine vector, allowing for replication competent viruses to be used to present heterologous antigen at mucosal surfaces for multiple rounds of vector replication, much like a live attenuated vaccine. Coronavirus genomes also can be engineered such that recombination with naturally circulating strains yields a dead virus. We recently completed the development of a reverse genetics system for HCoV OC43, which now makes it technically feasible to develop a HCoV OC43-based vaccine vector. In this phased innovation R21/R33 project we propose to engineer the HCoV OC43 genome as a multiple heterologous gene expression vector for SIV, which we will assess using the SIVsmE660/macaque model. In the R21 proof-of-concept phase we will: (i) engineer HCoV OC43 to express the SIVsmH4 matrix/capsid (MA/CA) gene from different regions of the vector genome, and (ii) evaluate the systemic, mucosal, and cellular immunogenicity of MA/CA-expressing HCoV OC43 vectors in mice. In the R33 phase we will: (i) characterize infectivity of HCoV OC43 in macaques, (ii) engineer and validate a recombination-resistant HCoV OC43 construct to express up to four SIVsmH4 proteins-Gag, Env, Nef and Vif, and (iii) vaccinate macaques with the multigene HCoV OC43 vector and assess vaccine efficacy by mucosal challenge with SIVsm E660. This project will provide the first critical evaluation of the potential use of common cold human coronaviruses as live mucosal vaccine vectors for HIV. PUBLIC HEALTH RELEVANCE: In the proposed study we will develop human coronaviruses, which cause about one- third of all common colds, as vaccine vectors to deliver HIV antigens. There are several potential attractive features of coronavirus vectors as vaccines for HIV, such as safety, simplicity in manufacturing, the ability to induce immune responses in sites of HIV transmission, and the ability to induce immune responses with a limited number of inoculations. We will evaluate the potential use of coronaviruses as HIV vaccine vectors using the SIV/macaque model.