NOVEL HIV VECTORS MIMIC NATURAL ANTIHIV RESPONSES

描述(改编自申请者的摘要)：对 一种有效的人类免疫缺陷病毒疫苗的研制 是疫苗产生多样和持久的抗艾滋病毒的能力 免疫反应。已有研究表明，减毒活病毒变异株可产生 这样的应对措施，因此为发展 一种艾滋病疫苗。活体关注的病毒变体的有效性可能 归因于它们模仿抗原处理途径的能力 会发生在感染野生型艾滋病毒期间。然而，一个主要的担忧是 随着减毒活疫苗的应用，疫苗的安全性也越来越高。 某些减毒猴免疫缺陷病毒(SIV)被激发 SIV攻击后猕猴的保护性免疫，但随后 在幼猴身上被证明是致病的。因此，迫切需要 开发一种能引起有效的抗艾滋病毒免疫反应的疫苗，但 缺乏致病潜能。申请者建议开发和测试在 借助辅助表达进行复制的体外HIV载体 利用核酶构建不产生重组腺病毒的安全载体 机制。这种有条件地复制人类免疫缺陷病毒 (CrHIV)载体将表达HIV蛋白，结果是在 在体内处理它们的抗原。长期目标是 确定是否可以开发crHIV载体来诱导多样化和 持久的抗艾滋病毒免疫反应，没有致病后果。至 实现这一目标，申请者计划全面严格评估 通过实现以下目标，这种方法在体外是可行的： (1)构建crHIV载体和辅助载体，并确定 在体外，crHIV载体可以借助辅助构建物进行繁殖； (2)评估包含在crhv载体中的核酶是否可以预防 在帮手介导的繁殖过程中出现传染性wt-HIV CRHIV；(3)确定抗原序列偏离程度 在crHIV载体的体外繁殖过程中发生；以及(4)确定 含crHIV的细胞是否可以感染wt-HIV以及crHIV是否 基因组与wt-HIV重组。申请者相信这些研究将 提供必要的初步数据，以便进行体内试验 非人灵长类动物模型中的媒介系统。

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.