A Novel HIV-1 Vaccine Targeting the 12 protease Cleavage Sites

描述（由申请人提供）：研制一种有效的预防艾滋病毒-1的疫苗已被证明是一项巨大的挑战。到目前为止，传统的疫苗方法在处理病毒感染免疫系统的关键组成部分，表现出巨大的抗原多样性和迅速突变方面已经失败或产生适度的效果。开发艾滋病毒-1的预防性疫苗需要新的方法和想法。爱德华·詹纳根据在挤奶女工身上观察到的自然免疫力，成功研制出了天花疫苗。因此，在高度暴露的未感染个体中记录的对HIV-1自然免疫的相关关系可能为开发HIV-1预防性疫苗提供重要线索。从一组高度暴露的HIV抗性内罗毕女性性工作者中HIV-1感染保护的免疫学相关性中，我们提出一种有效的HIV-1预防性疫苗应该针对HIV-1的关键位点，一种针对HIV-1的12个蛋白酶切割位点的疫苗可以预防HIV-1的获得。HIV蛋白酶是一种小的99个氨基酸的天冬氨酸酶，介导Gag、Gag- pol和Nef前体多蛋白的裂解。这一过程是高度特异性的，受暂时调控的，对感染性病毒颗粒的产生至关重要。产生感染性病毒粒子总共需要12个蛋白水解反应。因此，对HIV-1的12个蛋白酶切割位点产生免疫应答的疫苗将具有几个主要优势。首先，宿主的免疫反应可以在病毒在宿主体内永久存在之前将其摧毁。其次，疫苗可以迫使病毒积累突变，消除HIV蛋白酶的正常功能，从而消除传染性病毒粒子。第三，将免疫反应限制在这些位点可以避免分散的免疫反应，这些免疫反应通常会产生不必要的炎症反应，过度的免疫激活，并吸引更多的HIV- 1感染，建立和传播目标。为了验证这一假设，我们将毛里求斯食蟹猴和致病性SIVmac251作为实验模型，并将SIVmac239的12个蛋白酶裂解位点重叠的肽作为免疫原，与全Gag和全Env作为免疫原进行比较。我们将通过a)改良的水疱性口炎病毒（VSV）载体系统递送这些免疫原，该载体系统能够靶向树突状细胞并产生强大的免疫反应；B)纳米结构粘膜递送系统。对感染的保护将通过猕猴抵抗反复低剂量阴道内致病性SIVmac251攻击的能力来检验。次要结果如病毒载量设定点和CD4+ T细胞下降也将进行比较。病毒适应度分析将验证集中的免疫反应可以驱动有害的病毒突变，产生适应度和传播力减弱的病毒。确认这一假设和疫苗方法将改变艾滋病毒疫苗开发的范式，并开发出有效的预防性艾滋病毒疫苗。

DESCRIPTION (provided by applicant): Developing an effective preventative vaccine for HIV-1 has proved to be an enormous challenge. The classical vaccine approach has failed thus far or produced modest efficacy in dealing with a virus infects a key component of immune system and exhibits great antigenic diversity and mutates rapidly. Novel approaches and ideas are needed to develop a preventative vaccine to HIV-1. Edward Jenner developed the successful smallpox vaccine based on the natural immunity observed in milkmaids. Thus, the correlates of natural immunity to HIV-1 documented in highly exposed uninfected individuals may provide a vital clue for the development of a preventative vaccine to HIV-1. Learning from immunologic correlates of protection from HIV-1 infection in a group of highly exposed HIV resistant Nairobi female sex workers, we propose that an effective preventative vaccine to HIV-1 should target key sites of HIV-1 and a vaccine targeting the 12 protease cleavage sites of HIV-1 can prevent HIV-1 acquisition. HIV protease is a small 99-amino acid aspartic enzyme that mediates the cleavage of Gag, Gag-Pol and Nef precursor polyproteins. The process is highly specific, temporally regulated and essential for the production of infectious viral particles. A total of twelve proteolytic reactions are required to generate an infectious virion. Therefore, a vaccine generating immune responses to the 12 protease cleavage sites of HIV-1 would have several major advantages. First, the host immune response could destroy the virus before its permanent establishment in the host. Second, the vaccine could force the virus to accumulate mutations eliminating the normal function of the HIV protease thus eliminating infectious virions. Third, restricting the immune responses to these sites can avoid distracting immune responses that often generate unwanted inflammatory responses, excess immune activation, and attract more targets for HIV- 1 infection, establishment and spread. To test this hypothesis we will use Mauritian Cynomolgus macaques and pathogenic SIVmac251 as an experimental model and peptides overlapping the 12 protease cleavage sites of SIVmac239 as immunogens to compare with full Gag and full Env as immunogens. We will deliver these immunogens with a) a modified vesicular stomatitis virus (VSV) vector system capable of targeting dendritic cells and generating robust immune responses; b) a nanostructure mucosal delivery system. The protection from infection will be examined by the ability of the macaques to resist repeated low dose intravaginal pathogenic SIVmac251 challenges. Secondary outcome such as viral load set point and CD4+ T cell decline will also be compared. Viral fitness analysis will be conducted to validate that the focused immune responses can drive deleterious viral mutation and produce virus of attenuated fitness and transmissibility. Confirmation of this hypothesis and vaccine approach will shift the paradigm of HIV vaccine development and develop an effective preventative HIV vaccine.