Optimization of rAAV Vector Strategies for HIV

项目1的总体目标是增强rAAV/HIV疫苗的免疫原性和有效性。 我们已经表明，单剂量的基于rAAV血清型2（rAAV 2）载体的第一代SIV疫苗在恒河猴中具有高度免疫原性。这些相同的疫苗在用致病性SIV攻击后显著降低了猕猴中的病毒负荷。最近，我们已经表明，另一种血清型（rAAV 1）是1 - 2个数量级更好的基因传递到肌肉比rAAV 2。这些意见表明：（i）目前的第一代疫苗可能是次优的;（ii）替代血清型载体可能允许显著增加转导（和免疫原性）;和（iii）替代血清型载体提供了“初免-加强”方案的可能性，其中避免了载体交叉中和抗体的诱导。在特定目标1中，我们将通过使用替代血清型（rAAV 1和rAAV 5）测试初免-加强方案来扩展这些观察结果，这些血清型在基因转移方面比rAAV 2更有效，并且在衣壳基因中具有遗传差异（无交叉反应抗体）。我们还将检查预先存在的对AAV的免疫对猕猴中rAAWSIV（和HIV）疫苗的免疫原性的影响。除了载体增强之外，我们已经测试了“非传统”分子佐剂以增强由rAAV疫苗产生的免疫应答，并且已经鉴定了有希望的候选物。在具体目标2中，我们将推进这些候选药物在猕猴中进行免疫原性试验。 基于该项目的数据，我们将在猕猴的免疫原性和攻毒实验中设计和测试第二代疫苗。最终攻毒试验将与项目4中提出的试验组合，其中第二代rAAV疫苗将与指导中和HIV- 1原代分离株的抗体基因表达的rAAV载体组合。

The overall objective for Project 1 is to enhance the immunogenicity and efficacy ofrAAV/HIV vaccines. We have shown that a single dose of a first generation SIV vaccine based on rAAV serotype 2 (rAAV2) vectors is highly immunogenic in rhesus macaques. These same vaccines significantly reduced viral burden in macaques after challenge with pathogenic SIV. More recently, we have shown that another serotype (rAAV1) is 1 - 2 orders of magnitude better at gene delivery to muscle than rAAV2. These observations suggest that: (i) the current first generation vaccine is probably sub-optimal; (ii) alternate serotype vectors might allow for dramatic increases in transduction (and immunogenicity); and, (iii) alternate serotype vectors offer the possibility of "prime-boost" regimens where the induction of vector cross-neutralizing antibodies is avoided. In Specific Aim 1, we will extend these observations by testing prime-boost regimens using alternate serotypes (rAAV1 and rAAV5) that are more efficient than rAAV2 at gene transfer and are genetically distinct in the capsid gene (no cross-reacting antibodies). We will also examine the effects of pre-existing immunity to AAV on the immunogenicity of rAAWSIV (and HIV) vaccines in macaques, in addition to vector enhancements, we have tested "non-traditional" molecular adjuvants to augment immune responses engendered by rAAV vaccines and have identified promising candidates. In Specific Aim 2, we will advance these candidates into immunogenicity trials in macaques. Building on the data from this Project, we will design and test a second generation vaccine in immunogenicity and challenge experiments in macaques. A final challenge trial will be combined with a trial proposed in Project 4 wherein the second generation rAAV vaccine will be combined with an rAAV vector that directs the expression of antibody genes that neutralize primary isolates of HIV- 1.