Investigating the Protective Efficacy of SIV/HIV T and B cell Immunity Induced by RNA Replicons

摘要 艾滋病毒预防性疫苗的开发将得益于免疫原和疫苗的产生。 可诱导针对突变的高功能CD8+T细胞反应组合的传递方式 受限制的表位和对HIV包膜三聚体的广泛中和抗体反应。因此，在这方面 提议，我们计划利用三个组成部分来实现这一目标：一种称为基于结构的方法 用于识别CD8+T细胞优先靶向的一组保护性表位的网络分析 自发性HIV控制者的反应，2)能够引发异源的包膜三聚体 中和抗体反应和3)和创新的自扩增RNA疫苗递送平台 复制子，可诱导强大的CD8+T细胞和体液免疫。应用了基于结构的网络 对SIV蛋白结构的分析，我们已经确定了一组受限制的突变(高度网络化) SIV表位受一组MAMU I类等位基因的限制。此外，我们还提供了令人信服的数据 证明RNA复制子能够诱导CD8+T细胞对高度联网的SIV表位的反应 恒河猴体内强烈的三聚体特异性抗体反应。有待确定的是， 功能性CD8+T细胞对高度联网的SIV表位的反应具有保护作用 异源挑战，要么单独进行，要么与抗体联合进行。因此，在本提案的目标1中，我们将 评估由高度联网的SIV表位组成的RNA复制子疫苗免疫原的保护效果 在一组20只恒河猴中。这些免疫的猕猴将平均分配给那些接种疫苗的人 模拟免疫或高度联网的SIV表位免疫(每组10只)。在免疫后， 将评估疫苗诱导的针对高度联网的SIV表位的CD8+T细胞反应，并 然后，接种疫苗的动物将受到重复的低剂量SHIV.BG505攻击。这些Shiv 挑战猕猴将每两周进行一次病毒载量、CD4计数和CD8+T细胞表型评估 在挑战期内以及挑战期之后的20周内。通过/不通过的标准涉及 T细胞免疫原性和疫苗接种对SHV病毒载量的影响将在 在目标2中，我们将评估基于RNA复制子的组合的免疫原性和有效性 用高度联网的SIV表位免疫原和HIV环境三聚体免疫原进行疫苗接种。这些被免疫的 猕猴将被平均分配给那些接受模拟免疫、HIV环境三聚体+模拟免疫的人 免疫和HIV Env三聚体和高度联网的SIV表位免疫原的组合(10% 组)。这些研究将有助于确定疫苗诱导的CD8+T细胞反应是否指向 高度网络化的表位可以单独或与抗体结合提供保护性好处- 基础疫苗接种。此外，这项工作将为自我放大的rna复制子疫苗提供关键支持。 提供平台，以开发有效的预防性艾滋病毒疫苗。

ABSTRACT The development of a prophylactic vaccine for HIV would benefit from the generation of immunogens and vaccine delivery modalities that can induce a combination of highly functional CD8+ T cell responses towards mutation constrained epitopes and broadly neutralizing antibody responses to the HIV envelope trimer. Thus, in this proposal, we plan to leverage three components towards this goal: an approach known as structure-based network analysis that was used to identify a set of protective epitopes preferentially targeted by CD8+ T cell responses in spontaneous HIV controllers, 2) an envelope trimer that is capable of eliciting heterologous neutralizing antibody responses and 3) and an innovative vaccine delivery platform of self-amplifying RNA replicons that can elicit both robust CD8+ T cell and humoral immunity. Having applied structure-based network analysis to SIV protein structures, we have already identified a set of mutation constrained (‘highly networked’) SIV epitopes restricted by an array of Mamu class I alleles. In addition, we have also produced compelling data demonstrating the ability of RNA replicons to induce CD8+ T cell responses to highly networked SIV epitopes and strong trimer-specific antibody responses in rhesus macaques. What remains to be determined is whether functional CD8+ T cell responses towards highly networked SIV epitopes have a protective benefit against heterologous challenge, either individually or in tandem with antibodies. Thus, in Aim 1 of this proposal we will assess the protective efficacy of a RNA replicon vaccine immunogen comprised of highly networked SIV epitopes in a group of 20 rhesus macaques. These immunized macaques will be divided equally between those receiving mock immunization or highly networked SIV epitope immunization (10 per group). Following immunization, vaccine-induced CD8+ T cell responses directed against highly networked SIV epitopes will be assessed and vaccinated animals would then be subjected to repeated low dose SHIV.BG505 challenge. These SHIV challenged macaques will have viral load, CD4 count and CD8+ T cell phenotype assessments every 2 weeks during the challenge period and for 20 weeks following the challenge period as well. Go/No-Go criteria regarding T cell immunogenicity and the effects of vaccination on SHIV viral loads will be established and evaluated at the end of year 2. In Aim 2, we will assess the immunogenicity and efficacy of a combined RNA replicon-based vaccination with a highly networked SIV epitope immunogen and HIV Env trimer immunogen. These immunized macaques will be divided equally between those receiving mock immunization, HIV Env trimer + mock immunization and a combination of both HIV Env Trimer and highly networked SIV epitope immunogens (10 per group). These studies will help determine whether vaccine-induced CD8+ T cell responses directed towards highly networked epitopes can provide a protective benefit either individually or in combination with antibody- based vaccination. Additionally, this work will provide critical support of the self-amplifying RNA replicon vaccine delivery platforms towards the development of an effective, prophylactic HIV vaccine.