Enhancing DNA vaccines using modified Bacterial Toxin A1 Subunits as adjuvants

使用改良细菌毒素 A1 亚基作为佐剂增强 DNA 疫苗

• 批准号: 7844676
• 负责人: Timothy R Fouts
• 金额: $ 50.99万
• 依托单位: PROFECTUS BIOSCIENCES, INC.
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-06-01 至 2013-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7844676
• 关键词: Acute; Adjuvant; Adjuvanticity; Animals; Antigens; Bacterial Toxins; CD4 Positive T Lymphocytes; Cell Count; Cells; Cholera Toxin; Chronic Phase; Clinical; Clinical Trials; DNA; DNA Vaccines; Devices; Disadvantaged; Dose; Electroporation; Enterotoxins; Evaluation; Exhibits; Frequencies; Genetic; Goals; Gold; Government; HIV; Heating; Human; Immune response; Infection; Infection Control; Infectious Agent; Interleukin-12; Lead; Macaca; Modeling; Mus; Pain; Persons; Phase; Point Mutation; SIV; SIV Vaccines; Small Business Innovation Research Grant; T cell response; Techniques; Testing; Therapeutic; Toxin; Vaccination; Vaccine Adjuvant; Vaccine Antigen; Viral Load result; Viremia; base; immunogenicity; improved; in vitro activity; in vivo; mouse model; mutant; plasmid DNA; prototype; public health relevance; response; success

DESCRIPTION (provided by applicant): Cholera toxin (CT) and the related heat-labile enterotoxin (LT) are AB toxins with cell targeting B domains and enzymatically active A domains. The enzymatically active A1 domains of both CT (CTA1) and LT (LTA1) have demonstrated particular promise as genetic adjuvants that can enhance the immunogenicity of DNA vaccines in small and large animals and may provide necessary boosting and dose sparing effects in humans. In our Phase I efforts, we identified mutants of CTA1 and LTA1 with enhanced enzymatic activity in vitro and enhanced adjuvanticity in vivo. We identified a mutant of LTA1 that induced anti-HIV and anti-SIV cellular responses in mice nearly 2-fold higher than those induced by the "gold-standard" adjuvant IL-12 plasmid DNA (pDNA) or in vivo electroporation. In this Phase II application, we propose screen additional mutants and select a lead A1 subunit adjuvant to compare its adjuvanticity to that of IL-12 pDNA and electroporation. Using a prototype SIV DNA vaccine, we will compare the magnitude and polyfunctionality of the T cell response in both mice and macaques. We will follow the macaque studies with a homologous SIV challenge to determine whether any of the quantitative and qualitative differences observed in the immune response are relevant to protection. We propose to achieve these goals through the following specific aims: Aim 1: Identify a lead A1 subunit adjuvant that induces comparable or superior immune responses to SIV vaccine antigens as compared to electroporation and IL-12 pDNA; Aim 2: Characterize the anti-SIV immune responses adjuvanted by the lead A1 subunit adjuvant vs. IL-12 pDNA and electroporation in a macaque model Aim 3: Determine if administration of a SIV pDNA vaccine adjuvanted by the lead A1 subunit provide protection from homologous SIVmac251 challenge that is superior to that provided by IL-12 pDNA and electroporation. If the lead A1 subunit genetic adjuvant proves to be superior to IL-12 pDNA in the homologous challenge model, this adjuvant will be further evaluated in a heterologous challenge model. 2 PUBLIC HEALTH RELEVANCE: The objective of this project is to develop an advanced DNA vaccine adjuvant based on a modified A1 subunit of cholera toxin or heat-labile enterotoxin with enhanced enzymatic activity and adjuvanticity. Such an adjuvant is needed to enhance the clinical utility of HIV DNA vaccination in humans.

描述（由申请人提供）：霍乱毒素（CT）和相关的热能型肠毒素（LT）是具有细胞靶向B结构域的AB毒素，并且具有酶活性的A域。 CT（CTA1）和LT（LTA1）的酶活性A1结构域已显示出特殊的希望，作为遗传佐剂，可以增强大小动物中DNA疫苗的免疫原性，并且可能会在人类中提供必要的提升和剂量的释放效应。在我们的第一阶段努力中，我们在体外酶活性增强了CTA1和LTA1的突变体，并增强了体内辅助性。我们确定了一个LTA1突变体，该突变体在小鼠中诱导抗HIV和抗SIV细胞反应，比“金标准”辅助IL-12质粒DNA（PDNA）或体内电穿孔高近2倍。在此II阶段应用中，我们提出了屏幕其他突变体，并选择铅A1亚基佐剂，以将其辅助性与IL-12 pDNA和电穿孔的辅助性进行比较。使用原型SIV DNA疫苗，我们将比较小鼠和猕猴中T细胞反应的大小和多功能性。我们将遵循与同源SIV挑战的猕猴研究，以确定免疫反应中观察到的任何定量和定性差异是否与保护有关。我们建议通过以下特定目的实现这些目标：目标1：确定铅A1亚基辅助剂，与电穿孔和IL-12 pDNA相比，诱导对​​SIV疫苗抗原的可比或优势免疫反应；目标2：表征由铅A1亚基辅助与IL-12 pDNA辅助的抗SIV免疫反应以及在猕猴模型中的电穿孔目标3：确定是否由铅A1亚基辅助的施用siv pDNA疫苗辅助，从而提供了SIVMAC251挑战的保护，从而提供了sivmac251挑战的保护。如果铅A1亚基遗传佐剂在同源挑战模型中被证明优于IL-12 pDNA，则将在异源挑战模型中进一步评估该辅助物。 2 公共卫生相关性：该项目的目的是基于改良的霍乱毒素A1亚基或热比利肠肠毒素的改良A1亚基，具有增强的酶活性和辅助性。需要这样的辅助物来增强人类HIV DNA疫苗接种的临床实用性。