Optimization of Salmonelle-HIV-1 DNA Vaccine Vectors

描述（由申请方提供）：本提案中研究的目标是确定沙门氏菌HIV-1 DNA疫苗载体配置，该配置可在粘膜和全身免疫区室中诱导持久、高滴度的HIV-1中和抗体应答。 沙门氏菌载体递送DNA疫苗并在粘膜和全身隔室中诱导免疫应答的能力支持了将该载体用于递送表达构象受限的HIV-1 Env免疫原的DNA疫苗的想法。 此外，在用沙门氏菌gp 120 DNA疫苗载体致敏的小鼠中，在用gp 120蛋白进行两次胃肠外加强接种后，对gp 120产生了强烈的体液应答;相反，在用对照沙门氏菌构建体致敏并用gp 120蛋白进行两次加强接种的小鼠中，未发生此类应答（第3.3节）。 确定一种有效的疫苗接种方案，用于在粘膜初免后诱导对模型HIV-1抗原的高滴度抗体应答，这一点的重要性不容忽视。 然而，主要研究者（PI）提出，完全利用这种廉价的口服疫苗载体需要在没有异源疫苗形式加强的情况下产生这种应答。 在这方面，由第一代沙门氏菌Env/gp 120 DNA疫苗载体诱导的对HIV-1的应答主要是细胞介导的（（1）;附录1）。 尽管如此，上述体液引发属性表明发生了低剂量免疫原表达，这诱导了记忆性T辅助细胞和B细胞反应（12-16）。 通过扩展，该提议的中心假设是，用沙门氏菌HIV-1 DNA疫苗载体接种后对HIV-1的抗体应答的幅度与DNA疫苗递送效率和宿主细胞中的免疫原表达直接相关。 为了检验这一假设，将在用沙门氏菌载体接种的小鼠中测量粘膜和全身抗体应答的效力和持续时间，所述沙门氏菌载体携带设计用于优化DNA疫苗递送和免疫原表达的修饰。 预计这种方法将为开发廉价的口服HIV-1疫苗提供基本信息。

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.