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: 8244560
• 负责人: Timothy R Fouts
• 金额: $ 95.29万
• 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 2013-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8244560
• 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; enterotoxin LT; 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）和相关的不耐热肠毒素（LT）是AB毒素，具有细胞靶向B结构域和酶活性A结构域。 CT (CTA1) 和 LT (LTA1) 的酶活性 A1 结构域已被证明作为遗传佐剂具有特殊的前景，可以增强小型和大型动物中 DNA 疫苗的免疫原性，并可能在人类中提供必要的加强和剂量节省效应。在我们的第一阶段工作中，我们鉴定了 CTA1 和 LTA1 的突变体，其体外酶活性增强，体内佐剂性增强。我们鉴定了 LTA1 的突变体，它在小鼠体内诱导的抗 HIV 和抗 SIV 细胞反应比“金标准”佐剂 IL-12 质粒 DNA (pDNA) 或体内电穿孔诱导的反应高出近 2 倍。在此 II 期应用中，我们建议筛选其他突变体并选择先导 A1 亚基佐剂，以将其佐剂性与 IL-12 pDNA 和电穿孔的佐剂性进行比较。使用 SIV DNA 疫苗原型，我们将比较小鼠和猕猴 T 细胞反应的强度和多功能性。我们将通过同源 SIV 攻击来跟踪猕猴研究，以确定在免疫反应中观察到的任何定量和定性差异是否与保护相关。我们建议通过以下具体目标来实现这些目标： 目标 1：确定一种领先的 A1 亚基佐剂，与电穿孔和 IL-12 pDNA 相比，该佐剂可诱导对 SIV 疫苗抗原相当或更好的免疫反应；目标 2：在猕猴模型中表征先导 A1 亚基佐剂与 IL-12 pDNA 和电穿孔佐剂的抗 SIV 免疫反应 目标 3：确定施用先导 A1 亚基佐剂的 SIV pDNA 疫苗是否能提供优于 IL-12 pDNA 和电穿孔所提供的针对同源 SIVmac251 攻击的保护。如果在同源攻击模型中证明先导 A1 亚基遗传佐剂优于 IL-12 pDNA，则将在异源攻击模型中进一步评估该佐剂。 2 公共健康相关性：该项目的目标是开发一种基于霍乱毒素或不耐热肠毒素的改良 A1 亚基的先进 DNA 疫苗佐剂，具有增强的酶活性和佐剂作用。需要这样的佐剂来增强人类HIV DNA疫苗接种的临床效用。