Epitope optimization for heterologous prime-boost HIV vaccines

 描述（由申请人提供）：由于RV 144试验和许多最近的研究，异源初免-加强HIV疫苗策略已成为引发免疫应答的主要方法，可以保护免受HIV感染。然而，异源方法相对于同源方法的分子基础还没有很好地理解。特别是，对载体或DNA引发免疫的免疫应答，然后通过蛋白质加强免疫扩增，是复杂和模糊的。在这个建议中，我们将进行实验，可能会澄清未知的，基本方面的免疫反应的总理，是由蛋白质加强放大。为了测试这一点，我们将在异源初免-加强实验中控制许多因素，仅改变初免和加强之间的构象B细胞表位。我们的创新假设是，在启动时B细胞表位的构象影响了在加强时那些自身相同的表位。将用构建成表达或排除特异性免疫原性HIV可变环表位的DNA引物阵列对兔进行免疫，然后用专门携带这些表位的免疫聚焦蛋白免疫原进行加强。我们期望观察初免中构象表位的表达是否放大或延迟中和素抗体从蛋白加强上提供的自身相同表位的引发。这些结果将清楚地为选择或设计用于引发免疫的HIV env基因提供第一个一致的基本原理。因此，这个探索性的R21项目将为一个独特的长期研究计划奠定基础，该计划将研究异源初免-加强策略中初免和加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HIV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.