NOVEL HIV VECTORS MIMIC NATURAL ANTIHIV RESPONSES

描述（改编自申请人摘要）： 研制有效的人体免疫机能丧失病毒（艾滋病毒）疫苗 是疫苗能够产生多种持久的抗艾滋病毒抗体， 免疫反应 减毒活病毒变体已显示产生 这种反应，因此，为发展提供了最大的希望， 艾滋病疫苗 减毒活病毒变体的有效性可能 归因于它们模仿抗原加工途径的能力， 会在感染野生型HIV时发生。 然而，一个主要的问题是， 与减毒活HIV作为疫苗的应用相比，它们的安全性。 某些减毒猴免疫缺陷病毒（SIVS）引起 恒河猴SIV攻击后的保护性免疫，但随后 在幼年猴子中被证明是致病的。 因此，迫切需要 开发一种疫苗，激发有效的抗艾滋病毒免疫反应， 缺乏致病潜力。 申请人建议开发和测试 在辅助表达的帮助下复制的体外HIV载体 使用核酶作为安全剂而不产生wt-HIV的构建体 机制 这种有条件复制的人类免疫缺陷病毒 （crHIV）载体将表达HIV蛋白，并且因此，在细胞中模拟wt-HIV。 它们的抗原在体内的加工过程。 长期目标是 确定是否可以开发crHIV载体，以引起多样化和 持续的抗HIV免疫反应，无致病后果。 到 为了实现这一目标，申请人计划严格评估整体 通过实现以下目标，在体外研究这一方法的可行性： (1)构建crHIV载体和辅助构建体，并确定是否 所述crHIV载体可以在辅助构建体的帮助下在体外增殖; (2)为了评估crHIV载体中包含的核酶是否可以预防 感染性wt-HIV在辅助病毒介导的传播过程中的出现 crHIV;（3）确定抗原序列差异的程度， 在crHIV载体的体外增殖期间发生;以及（4）确定 含有crHIV的细胞是否可以被wt-HIV感染以及crHIV是否 基因组与野生型HIV重组。 申请人相信这些研究将 提供必要的初步数据，以进行体内试验， 在非人灵长类动物模型中的载体系统。

DESCRIPTION (adapted from applicant's abstract): A critical challenge for the development of an effective human immunodeficiency virus (HIV) vaccine is the ability of the vaccine to generate a diverse and persistent anti-HIV immune response. Live-attenuated viral variants have been shown to generate such responses, and hence, offer the greatest promise for the development of an HIV vaccine. The effectiveness of live attentuated viral variants could be attributed to their abiltiy to mimic the antigen processing pathways that would occur during infection with wild-type HIV. However, a major concern with the application of live attenuated HiVs as vaccines is their safety. Certain attenuated simian immunodeficiency viruses (SIVS) elicited protective immunity in rhesus macaques after SIV challenge, but subsequently proved to be pathogenic in juvenile monkeys. Thus, there is an urgent need to develop a vaccine which elicits an effective anti-HIV immune response but lacks pathogenic potential. The applicants propose to develop and test in vitro HIV vectors that would replicate with the aid of a helper-expression construct without generating wt-HIV by using ribozymes as a safety mechanism. Such conditionally replicating human immunodeficiency virus (crHIV) vectors would express HIV proteins and, as a result, mimic wt-HIV in the processing of their antigens in vivo. The long-term goal is to determine whether crHIV vectors can be developed to elicit a diverse and persistent anti-HIV immune response without pathogenic consequences. To achieve this goal, the applicants plan to rigorously evaluate the overall feasibility of this approach in vitro by carrying out the following aims: (1) to construct crHIV vector and helper constructs and determine whether the crHIV vector can propagate with the aid of a helper construct in vitro; (2) to assess whether ribozymes contained within crHIV vectors can prevent the emergence of infectious wt-HIV during helper-mediated propagation of crHIV; (3) to determine the degree of antigenic sequence divergence that occurs during propagation of the crHIV vector in vitro; and (4) to determine whether crHIV-containing cells can be infected with wt-HIV and whether crHIV genomes recombine with wt-HIV. The applicants believe these studies will provide the necessary preliminary data to proceed to in vivo testing of this vector system in a non-human primate animal model.