Development of HSV Vectors as AIDS Vaccines

艾滋病毒疫情继续有增无减，特别是在撒哈拉以南非洲和亚洲部分地区。尽管有许多艾滋病疫苗在考虑之中，但只有一种疫苗在第三阶段试验中进行了测试，即gp120包膜蛋白疫苗，它没有显示出保护作用。该项目建议测试和开发新的复制缺陷单纯疱疹病毒疫苗载体，以前的工作已经表明，这种载体可以在免疫猕猴中诱导T细胞和抗体反应，包括针对SIV蛋白的中和抗体。此外，在静脉致病性SIV攻击后，免疫猕猴的病毒载量减少。这些HSV重组载体是仅有的几种免疫方法中的一种，可以通过黏膜SIV攻击或静脉SIV攻击在恒河猴体内对病原性SIVmac239攻击感染产生保护。因此，在这一点上，继续发展这些载体是非常合理的。然而，载体和表达的抗原的转基因表达水平和免疫原性有待优化。本申请中提出的研究测试了应增强该载体系统的各种修改，并进一步开发了这种新型疫苗载体系统。在本方案中，我们的具体目标是：1.通过验证HIV Gag蛋白表达增加d106的假设，在HSV-1 d106株中构建改进的HSV-1重组疫苗载体 通过验证通过突变HIV env的V1/V2环或突变env蛋白上的糖基化位点可以增强对env的抗体应答的假说，通过检验d106载体共表达Toll样受体配体SARS病毒刺突蛋白可以增强免疫的假说，载体将增强小鼠的CD8+T细胞免疫应答。2.验证不同黏膜部位免疫可诱导粘膜免疫的假说。3.验证HSV病毒粒子上的糖蛋白在免疫逃避中的作用，从而证明HSV疫苗载体在HSV免疫小鼠中是有效的。4.通过检测载体DNA的持久性、神经毒力、潜伏感染和免疫缺陷动物的安全性，确定HSV c/106重组载体的生物学特性。

The HIV epidemic continues unabated, in particular in sub-Saharan Africa and parts of Asia. Despite the numerous AIDS vaccines under consideration, only one has been tested in phase III trials, the gp120 envelope protein vaccine, and it showed no protective effect. This project proposes to test and develop novel replication-defective herpes simplex virus vaccine vectors, which have been shown in previous work to induce both T cell and antibody responses, including neutralizing antibodies, against SIV proteins in immunized rhesus macaques. Furthermore, the immunized macaques showed reduced viral loads after intravenous pathogenic SIV challenge. These HSV recombinant vectors are among only a few immunization approaches that have elicited any protection in rhesus macaques against pathogenic SIVmac239 challenge infection either by mucosal SIV challenge or intravenous SIV challenge. Therefore, the continued development of these vectors is highly justified at this point. Nevertheless, the level of transgene expression and immunogenicity of the vector and expressed antigens needs to be optimized. The proposed research in this application tests various modifications that should enhance this vector system and further the development of this novel vaccine vector system. In this proposal our specific aims are 1. To construct improved HSV-1 recombinant vaccine vectors in the HSV-1 d106 strain by testing the hypothesis that increasing expression of HIV gag protein by d106 vectors will increase CD8+ T cell immune responses in mice, by testing the hypothesis that mutating the V1/V2 loops of HIV env or mutating the glycosylation sites on env protein will enhance the antibody responses to env, by testing the hypothesis that co-expression of a Toll-like receptor ligand, the SARS virus spike protein, by the d106 vector will increase immune. 2. To test the hypothesis that mucosal immunity can be induced by immunization at various mucosal sites. 3. Test the hypothesis that glycoproteins on the HSV virion play a role in immune evasion so that HSV vaccine vectors are efficacious in HSV-immune mice. 4. Define the biological properties of the HSV c/106 recombinant vectors by testing persistence of vector DNA, neurovirulence, latent infection, and safety in immunodeficient animals.