A New DNA Vaccine Against HIV Disease in Macaques

描述(申请人提供)：目前，使用猕猴来评估艾滋病毒疫苗的效力表明，尽管多种类型的疫苗可以钝化致病挑战病毒的急性感染，但没有任何疫苗可以预测地预防感染和伴随感染而不可避免的病毒潜伏期的建立。因此，疫苗的负担是保持保护性反应，以防止病毒从潜伏感染的细胞反弹。经过多年的保护后，病毒突破的发生率不断增加，这表明可能有必要定期实施暴露后加强治疗，以无限期地防止病毒反弹。考虑到这一点，我们调查了使用一种新型DNA疫苗的可行性，这种疫苗可以预防性使用，并在暴露于致病病毒后继续使用。我们选择SHIVku2 DNA作为慢病毒载体，表达几个HIV基因，其中包括env和Gag，它们可以定制成与任何特定HIV亚型的基因相匹配。疫苗骨架由SIV启动子/增强子序列组成，驱动高复制能力的SHIVku2基因组的表达，其中RT、整合酶、vif和3‘LTR被删除(Delta4)，而rev和Tat被保留。概念验证表明，表达SIV Gag和X4 HIV env的delta4DNA诱导了对异源X4Shiv的保护，而不需要病毒蛋白的加强，并且免疫可以在攻击后继续进行。然而，要证明对不同亚型R5病毒的有效性，需要提供表达这些病毒env/Gag的致病SHIV。在这项建议的目标1中，我们将通过将B和C亚型患者分离株的env/gag基因整合到高致病性SHIVku2的基因组中来开发新的致病SHIV。这些病毒随后将在Aim 3中用作挑战，以测试表达HIV B和C亚型env和Gag的新型delta4 Shiv DNA疫苗的有效性。我们将使用细胞因子GM-CSF和IL-15的DNA作为佐剂，以提高已经成功的DNA疫苗诱导的长期免疫的幅度和持续时间，这取决于在Aim 2中的研究结果，在该研究中，将使用小鼠来评估这些潜在的佐剂效果。然后我们将扩展目标4中的研究参数，在那里我们将确定可能使用细胞因子佐剂加强的DNA疫苗是否可以在抗逆转录病毒治疗的掩护下用于免疫慢性感染的动物，以重新诱导在治疗期间可能会减弱的免疫力。在药物治疗被取消后，疫苗接种将继续进行。这些研究将适用于HAART下的艾滋病毒感染者。

DESCRIPTION (provided by applicant): Currently, use of macaques to evaluate efficacy of HIV vaccines has shown that although numerous types of vaccines can blunt acute infections by pathogenic challenge viruses, no vaccine can predictably prevent infection and the inevitable establishment of viral latency that accompanies the infection. The burden on the vaccine therefore is to maintain protective responses to prevent rebound of the virus from latently infected cells. The increasing incidence of virus breakthroughs after years of protection suggests that it may be necessary to administer post-exposure boosts at regular intervals in order to indefinitely maintain prevention of virus rebound. With this in mind, we investigated the feasibility of using a new type of DNA vaccine that could be used prophylactically and continued after exposure to pathogenic virus. We chose SHIVku2 DNA as a lentiviral vector that expresses several HIV genes, among which are the env and gag that can be tailored to match the genes of any particular subtype of HIV. The vaccine backbone consists of SIV promoter/enhancer sequences driving expression of the high-replication-competent SHIVku2 genome from which the rt, integrase, vif, and 3 'LTR were deleted (delta4), and the rev and tat retained. Proof of concept has shown that the delta4 DNA expressing SIV gag and X4 HIV env induced protection against heterologous X4 SHIV without the benefit of viral protein boosts and that immunization could be continued following challenge. However, proof of efficacy against R5 viruses of different subtypes would require availability of pathogenic SHIVs expressing the env/gag of these viruses. In Aim 1 of this proposal, we will develop new pathogenic SHIVs that express the env/gag of patient isolates of subtypes B and C by incorporating these genes into the genome of highly pathogenic SHIVku2. These viruses will then be used in Aim 3 as challenge to test the efficacy of new delta4 SHIV DNA vaccines expressing env and gag of HIV subtypes B and C. We will use DNAs of cytokines GM-CSF and IL-15 as adjuvants to boost the magnitude and duration of long term immunity induced by the already successful DNA vaccine, depending on results of studies in Aim 2, in which mice will be used to assess these potential adjuvanting effects. We will then extend the study parameters in Aim 4, where we will determine whether the DNA vaccine, possibly strengthened with the cytokine adjuvants, can be used to immunize chronically infected animals under the cover of antiretroviral therapy, to re-induce immunity that would have waned during therapy. Vaccine boosts will continue after drug therapy had been withdrawn. These studies will be applicable to HIV infected persons under HAART.