Optimization of Salmonelle-HIV-1 DNA Vaccine Vectors

描述（由申请人提供）：本提案的研究目标是确定一种沙门氏菌HIV-1 DNA疫苗载体结构，该结构可在粘膜和全身免疫区诱导持久的、高滴度的HIV-1中和抗体反应。沙门氏菌载体递送DNA疫苗和诱导粘膜和系统隔室免疫反应的能力支持了利用该载体递送表达构象受限的HIV-1 Env免疫原的DNA疫苗的想法。此外，用沙门氏菌gp120 DNA疫苗载体进行两次肠外强化接种后，小鼠对gp120产生了强烈的体液应答；相比之下，用对照沙门氏菌构建物启动并用gp120蛋白增强两次的小鼠没有出现这种反应（第3.3节）。确定了一种有效的疫苗接种方案，在粘膜启动后诱导对模型HIV-1抗原的高滴度抗体反应，其意义不容忽视。然而，首席研究员（PI）建议，完全利用这种廉价的口服疫苗载体，需要在没有异种疫苗模式促进的情况下产生这种反应。在这方面，第一代沙门氏菌Env/gp120 DNA疫苗载体诱导的对HIV-1的应答主要是细胞介导的(1)；应用。1)。尽管如此，上述体液启动特性表明低剂量免疫原表达的发生，诱导记忆T辅助和B细胞反应（12-16）。进一步地说，这一提议的中心假设是，接种沙门氏菌HIV-1 DNA疫苗载体后，抗体对HIV-1的反应程度与DNA疫苗的递送效率和宿主细胞中免疫原的表达直接相关。为了验证这一假设，将在接种沙门氏菌载体的小鼠中测量粘膜和全身抗体反应的效力和持续时间，沙门氏菌载体携带旨在优化DNA疫苗递送和免疫原表达的修饰。预计这种方法将提供与研制廉价的口服艾滋病毒-1疫苗密切相关的基本信息。

DESCRIPTION (provided by applicant): The goal of the research in this proposal is to identify a Salmonella HIV-1 DNA vaccine vector configuration that induces durable, high-titer neutralizing antibody responses to HIV-1 in the mucosal and systemic immune compartments. The capacity of Salmonella vectors to deliver DNA vaccines and induce immune responses in the mucosal and systemic compartments supports the idea to deploy this vector to deliver DNA vaccines that express conformationally constrained HIV-1 Env immunogens. Moreover, strong humoral responses to gp120 developed in mice primed with a Salmonella gp120 DNA vaccine vector following two parenteral booster vaccinations with gp120 protein; in contrast, no such responses occurred in mice primed with the control Salmonella construct and boosted twice with gp120 protein (Section 3.3). The significance of having identified an effective vaccination protocol for the induction of high-titer antibody responses to a model HIV-1 antigen following a mucosal prime will not be overlooked. However, the Principal Investigator (PI) proposes that the complete utilization of this inexpensive oral vaccine vector necessitates that such responses arise without a heterologous vaccine modality boosts. In this regard, the responses induced by a first-generation Salmonella Env/gp120 DNA vaccine vectors to HIV-1 were predominantly cell-mediated ((1); App. 1). Nonetheless, the afore mentioned humoral priming attribute suggests the occurrence of low-dose immunogen expression, which induced memory T helper and B cell responses (12-16). By extension, the central hypothesis of this proposal is that the magnitude of the antibody responses to HIV-1 following vaccination with a Salmonella HIV-1 DNA vaccine vector is directly linked to the efficiency DNA vaccine delivery and immunogen expression in host cells. To test this hypothesis the potency and duration of mucosal and systemic antibody responses will be measured in mice vaccinated with Salmonella vectors that carry modifications designed to optimize DNA vaccine delivery and immunogen expression. It is projected that this approach will provide fundamental information germane to the development of an inexpensive oral HIV-1 vaccine.