Conserved Elements Therapeutic DNA Vaccine for HIV

描述(由申请人提供)： 我们之前的研究表明，尽管使用了次优的ART方案，治疗性DNA疫苗诱导的粘膜反应与SIV感染猕猴肠道内病毒的显著减少相关。这种疫苗刺激T细胞反应，将病毒抑制到低/不可检测的水平，并在停止ART后在约50%的动物中提供了持久的“功能治愈”。我们建议通过以下方式使治疗性疫苗更有效：1)使用更有效的药物组合(CART)来最大化疫苗的效果；2)使用粘膜佐剂(LT)来靶向针对肠道相关淋巴组织中残留病毒的免疫反应；以及3)使用新型SIV保守元件(CE)DNA疫苗来使T细胞反应集中在高度保守的病毒序列上，如果这些序列发生突变，将产生更大的适应成本。我们的总体假设是，疫苗诱导的功能性治愈是由强大的粘膜CD8反应介导的，将这些反应集中在最大限度抑制感染的肠道和针对更保守的表位，这些表位抑制了更广泛的可能的病毒变异，并选择了更适合成本更高的逃逸突变，这将最大限度地阻止残留病毒在停止CART后从潜伏库中涌出的能力。在操作上，使用优化的CART和粘膜靶向，我们将比较传统的全抗原和CE DNA疫苗针对保守的病毒序列增加粘膜和系统CD8反应的频率和强度的能力，以及它们对病毒进化和适合性的影响，并确定这些因素在功能性治愈中的作用。我们的具体目标是：1)确定表达全抗原的LT佐剂传统SIV DNA疫苗与更有效的CART一起使用时的治疗效果。2)确定SIV CE免疫原是否会提高治疗效果。3)确定功能性治疗的免疫和病毒学机制。通过拟议的研究，我们将确定疫苗诱导功能性治愈的病毒学和免疫学特征，并确定新型CE DNA疫苗诱导SIV感染功能性治愈的可行性。

DESCRIPTION (provided by applicant): Our previous studies have shown that therapeutic DNA vaccine induction of mucosal responses correlated with significant reduction of virus in the gut of SIV-infected macaques despite the use of a suboptimal ART regimen. This vaccine stimulated T cell responses that suppressed virus to low/undetectable levels and afforded a durable "functional cure" in ~50% of the animals after stopping ART. We propose here to make therapeutic vaccination even more effective by 1) using a more potent combination of drugs (cART) to maximize the effects of the vaccine, 2) using a mucosal adjuvant (LT) to target immune responses to residual virus in gut associated lymphoid tissue, and 3) use of a novel SIV conserved elements (CE) DNA vaccine to focus T cell responses against highly conserved viral sequences that if mutated will impose greater fitness cost. Our overarching hypothesis is that vaccine-induced functional cure is mediated by strong mucosal CD8 responses, and that focusing these responses to the gut in maximally suppressed infections and against more conserved epitopes, which suppress a wider range of possible viral variants and select for more fitness-costing escape mutations, will maximally disable the ability of residual viruses to emerge from the latent reservoir after stopping cART. Operationally, using optimized cART and mucosal targeting we will compare a traditional whole antigen and a CE DNA vaccine for the ability to increase the frequency and strength of mucosal and systemic CD8 responses against conserved viral sequences, and for their impact on viral evolution and fitness, and determine the role of these factors in a functional cure. Our specific aims are to: 1) Determine therapeutic efficacy of an LT-adjuvanted traditional SIV DNA vaccine expressing whole antigens when used with more potent cART. 2) Determine if an SIV CE immunogen will improve therapeutic efficacy. 3) Define immune and virological mechanisms underlying functional cures. Through the proposed studies we will define the virological and immune profile of a vaccine-induced functional cure and determine the feasibility of a novel CE DNA vaccine to induce a functional cure of SIV infection.