Epitope optimization for heterologous prime-boost HIV vaccines

 描述(由申请人提供)：由于RV144试验和许多最近的研究，异种主要增强艾滋病毒疫苗策略已经成为诱导免疫反应的主要方法，可以预防艾滋病毒感染。然而，异源方法相对于同源方法的分子基础还没有被很好地理解。特别是，对载体或DNA启动免疫的免疫反应，然后通过蛋白质增强免疫放大，是复杂和模糊的。在这项提案中，我们将进行实验，以澄清由蛋白质增强放大的对质数的意外、基本的免疫反应。为了测试这一点，我们将在一个异源的质数-增强型实验中控制许多因素，只改变质数和增强型之间的构象B细胞表位。我们的创新假设是，启动时B细胞表位的构象会影响那些自身相同的表位。将用一系列DNA引物免疫兔子，这些DNA引物旨在表达或排除特定的免疫原性HIV可变环表位，然后用免疫聚焦蛋白免疫原加强免疫，该免疫聚焦蛋白免疫原仅携带这些表位。我们希望观察一个构象表位的表达是放大还是抑制从蛋白质Boost上提供的自我相同表位中激发中和蛋白抗体。这一结果将清楚地为选择或设计HIV env基因用于启动免疫提供第一个一致的理论基础。因此，这一探索性的R21项目将为一项独特的长期研究计划奠定基础，该计划将研究异种Prime-Boost策略中启动和增强免疫之间相互作用的分子细节。这些细节可能对设计有效的艾滋病毒疫苗至关重要。

 DESCRIPTION (provided by applicant): As a result of the RV144 trial and numerous recent studies, heterologous prime-boost HIV vaccine strategies have emerged as the leading approach to elicit immune responses that could protect against HIV infection. The molecular basis of the heterologous approach over homologous approaches is not well understood, however. In particular, immune responses to vector or DNA priming immunizations that are then amplified by protein boost immunization are complex and obscure. In this proposal, we will perform experiments that may clarify unsuspected, fundamental aspects of the immune responses to the prime that are amplified by the protein boost. To test this, we will control for many factors in a heterologous prime-boost experiment, varying only the conformational B-cell epitopes between prime and boost. Our innovative hypothesis is that the conformation of B-cell epitopes in the prime influences those self-same epitopes in the boost. Rabbits will be immunized with an array of DNA primes constructed to express or exclude specific immunogenic HIV variable loop epitopes and then boosted with an immunofocused protein immunogen that exclusively bears those epitopes. We expect to observe whether the expression of a conformational epitope in the prime amplifies or retards elicitation of neutralizin antibodies from that self-same epitope provided on the protein boost. The results will clearly provide the first consistent rationale for selecting or designing HIV env genes for use in priming immunizations. This exploratory R21 project will thus form the foundation for a unique long-term research program into the molecular details of the interaction between priming and boosting immunizations in a heterologous prime-boost strategy. These details may be crucial for designing an efficacious HIV vaccine.