Prevention of AIDS

预防艾滋病

• 批准号: 8763086
• 负责人: BARBARA K FELBER
• 金额: $ 216.86万
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8763086
• 关键词: AIDS Vaccines; AIDS prevention; Address; Adjuvant; Affect; Amino Acid Sequence; Animals; Antigens; CD8B1 gene; Clinical Trials; Code; Codon Nucleotides; Cytokine Gene; DNA; DNA Vaccines; DNA delivery; Development; Disease; Electroporation; Elements; Epidemic; Epitopes; Equilibrium; Escape Mutant; Frequencies; Gagging; Gene Expression; Goals; HIV; HIV Infections; HIV Vaccine Trials Network; HIV vaccine; HIV-1; Highly Active Antiretroviral Therapy; Humoral Immunities; Immune response; Immunization; Immunotherapeutic agent; Individual; Injection of therapeutic agent; Interleukin-12; Intramuscular Injections; Longevity; Macaca; Macaca mulatta; Memory; Methodology; Methods; Modality; Modeling; Molecular; Mucosal Immune Responses; Mus; Muscle; Nuclear; Nucleotides; Post-Translational Protein Processing; Prevention; Preventive; Production; Proteins; Proteome; RNA; Regimen; Relative (related person); Reporting; SIV; Subgroup; T-Lymphocyte; Testing; Time; Transcript; Translations; Vaccinated; Vaccination; Vaccines; Variant; Viremia; Virus; Work; base; cytokine; cytotoxic; efficacy testing; experience; expression vector; immunogenic; immunogenicity; improved; in vivo; mRNA Expression; novel; novel vaccines; plasmid DNA; prototype; response; therapeutic vaccine; trafficking; vaccination strategy; vaccine development; vaccine efficacy; vaccine-induced immunity; vector; vector vaccine

Our work focuses on the use of DNA-based vaccine strategies both as preventive and immunotherapeutic approaches. We have generated efficient SIV and HIV DNA expression vectors. This work is based on our previous recognition that RNA elements (called INS) present within the gag/pol and env coding regions of HIV are responsible for nuclear retention and instability of the transcripts in the absence of Rev, and that these elements can be eliminated by changing the nucleotide composition of the transcripts (RNA optimization; also referred to as codon optimization) without affecting the amino acid sequence. The immunogencity of the antigens was further improved by modifying the trafficking of the antigens. The introduced modifications of the proteins led to more efficient secretion of the SIV antigens resulting in increased cellular and humoral immune responses in the vaccinated mice or rhesus macaques. The immunogenicity of such molecules has been tested in mice and macaques. Studies in mice allowed us to test different DNA vectors and revealed that a combination of DNAs producing different forms of the same antigen generated more balanced immune responses, a desirable feature for an optimal AIDS vaccine. Different delivery methods of the HIV/SIV antigens are being tested. Another important aspect of HIV vaccine development is the selection of the antigens, which has to take into consideration the diversity of the different HIV clades and the identification of the critical epitopes able to induce relevant immune responses. We are working on optimizing antigens using approaches that use either a conserved epitope approach or mosaic molecules. Using DNA-only vaccination, we found that our optimized DNA vaccine vectors are able to induce potent immune responses able to protect from high viremia in the rhesus macaque/SIV challenge model. A limitation in using DNA as a vaccine is its relative inefficient delivery upon intramuscular injection. Recent developments to improve DNA delivery include in vivo electroporation. We reported that electroporation dramatically increased the efficiency of DNA delivery in both SIV experienced and ART-treated naive rhesus macaques, leading to greatly augmented antigen expression. We found that this vaccination method results in enhanced immune responses with a high frequency of circulating SIV-specific T cells, the presence of multifunctional T cells, and induction of both effector memory and central memory CD4 and CD8 SIV-specific T cells. We reported that the inclusion of IL-12 DNA as adjuvant led to improved quality of the responses. In addition to systemic immune responses, the use of this improved DNA vaccination methodology also induced mucosal responses, albeit only to a subgroup of animals. Although DNA electroporation provides a strong humoral immune response including neutralizing Ab development in macaques, we recently showed that a protein boost can induce higher levels of Ab. Importantly, we showed that injection of DNA and protein either unadjuvanted or adjuvanted in the same muscle at the same time increased Ab production and mucosal dissemination. DNA&Protein co-immunization is superior to vaccination with either of the two individual components in eliciting humoral immune responses. Perhaps more importantly, the vaccine regimen also induced potent long-lasting humoral immunity, detectable for 4 years after the last vaccination. Challenge of animals which received such optimized vaccination regimens showed a significant delay in virus acquisition and improvement in virological control of the highly pathogenic SIV challenge. Thus, efficient DNA delivery methods in combination with improved DNA vaccine cocktails and the inclusion of protein in the vaccine regimen resulted in greatly augmented and more balanced immune responses in vaccinated rhesus macaques. We reported a correlation of systemic and mucosal immune responses and virus acquisition as well as a correlation of cytotoxic cellular immune responses with virus control. An ideal HIV vaccine should provide protection against all HIV-1 variants. HIV sequence diversity and the presence of potential immunodominant "decoy" epitopes are hurdles in the development of an effective AIDS vaccine. To address these problems, we are exploring approaches to maximize immunological strength and breadth focusing on highly conserved regions of HIV to induce immune responses to nearly invariable proteome segments, essential for the function of the virus, while excluding responses to variable and potentially immunodominant "decoy" epitopes. We developed a prototype vaccine targeting regions within the p24gag (p24gagCE DNA vaccine). In proof-of-concept studies in mice and macaques, we demonstrated that immunization with this DNA elicits robust cellular and humoral immune responses against CE, which cannot be achieved by p55gag DNA vaccination. Importantly, we demonstrated that priming with CE DNA and boosting with p55gag DNA is an effective strategy to maximize responses against Gag, providing a novel concept to increase the magnitude and breadth of vaccination. The translation of this novel concept is currently being pursued in an HVTN/DAIDS-supported clinical trial with the aim to test whether our p24gagCE vaccine develops superior breath and magnitude of gag responses compared to the optimized gag immunogen (p55gag), which showed the highest immune response rate in HVTN clinical trials.

我们的工作重点是使用基于DNA的疫苗策略作为预防和免疫方法。我们已经产生了有效的SIV和HIV DNA表达载体。这项工作是基于我们以前的认识，即RNA元件（称为INS）内存在的gag/pol和env编码区的HIV是负责核保留和不稳定的转录本在Rev的情况下，这些元件可以消除通过改变转录本的核苷酸组成（RNA优化;也称为密码子优化），而不影响氨基酸序列。通过修饰抗原的运输，进一步提高了抗原的免疫原性。引入的蛋白质修饰导致SIV抗原的更有效分泌，导致接种疫苗的小鼠或恒河猴中细胞和体液免疫应答增加。已经在小鼠和猕猴中测试了此类分子的免疫原性。对小鼠的研究使我们能够测试不同的DNA载体，并揭示了产生不同形式的相同抗原的DNA组合产生更平衡的免疫反应，这是最佳艾滋病疫苗的理想特征。目前正在测试艾滋病毒/SIV抗原的不同输送方法。HIV疫苗开发的另一个重要方面是抗原的选择，这必须考虑到不同HIV进化枝的多样性和能够诱导相关免疫应答的关键表位的鉴定。我们正致力于使用保守表位方法或镶嵌分子的方法来优化抗原。使用仅DNA疫苗接种，我们发现我们优化的DNA疫苗载体能够诱导有效的免疫应答，能够在恒河猴/SIV攻击模型中保护免于高病毒血症。使用DNA作为疫苗的限制是其在肌内注射时相对低效的递送。最近改进DNA递送的发展包括体内电穿孔。我们报道了电穿孔显著增加了SIV经历的和ART治疗的幼稚恒河猴中DNA递送的效率，导致大大增强的抗原表达。我们发现，这种疫苗接种方法导致增强的免疫应答，具有高频率的循环SIV特异性T细胞，多功能T细胞的存在，以及效应记忆和中央记忆CD 4和CD 8 SIV特异性T细胞的诱导。我们报道了IL-12 DNA作为佐剂的加入导致应答质量的改善。除了全身免疫应答之外，使用这种改进的DNA疫苗接种方法还诱导粘膜应答，尽管仅针对动物亚组。虽然DNA电穿孔提供了一个强大的体液免疫反应，包括中和抗体在猕猴的发展，我们最近表明，蛋白质加强可以诱导更高水平的抗体。重要的是，我们发现在同一肌肉中同时注射无佐剂或佐剂的DNA和蛋白质增加了Ab产生和粘膜传播。DNA和蛋白质联合免疫在诱导体液免疫应答方面上级单独免疫。也许更重要的是，疫苗方案还诱导了有效的持久体液免疫，在最后一次接种后4年内可检测到。接受这种优化的疫苗接种方案的动物的攻击显示出病毒获得的显著延迟和高致病性SIV攻击的病毒学控制的改善。因此，有效的DNA递送方法结合改进的DNA疫苗混合物和在疫苗方案中包含蛋白质导致接种的恒河猴中免疫应答大大增强和更平衡。我们报道了系统和粘膜免疫应答与病毒获得的相关性，以及细胞毒性细胞免疫应答与病毒控制的相关性。理想的艾滋病毒疫苗应提供针对所有HIV-1变体的保护。HIV序列的多样性和潜在的免疫显性“诱饵”表位的存在是开发有效的艾滋病疫苗的障碍。为了解决这些问题，我们正在探索的方法，以最大限度地提高免疫强度和广度，重点是高度保守的区域的艾滋病毒诱导免疫反应几乎不变的蛋白质组片段，病毒的功能至关重要，而不包括响应可变的和潜在的免疫显性的“诱饵”表位。我们开发了靶向p24 gag内区域的原型疫苗（p24 gagCE DNA疫苗）。在小鼠和猕猴的概念验证研究中，我们证明了用这种DNA免疫可以产生针对CE的强大的细胞和体液免疫应答，这是通过p55 gag DNA疫苗接种无法实现的。重要的是，我们证明了用CE DNA引发和用p55 gag DNA加强是最大化针对Gag的应答的有效策略，提供了增加疫苗接种的幅度和广度的新概念。这一新概念的转化目前正在HVTN/DAIDS支持的临床试验中进行，目的是测试我们的p24 gagCE疫苗是否与优化的gag免疫原（p55 gag）相比产生上级呼吸和gag应答的幅度，优化的gag免疫原在HVTN临床试验中显示出最高的免疫应答率。