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.

我们的工作着重于使用基于DNA的疫苗策略作为预防和免疫治疗方法。我们已经产生了有效的SIV和HIV DNA表达向量。这项工作是基于我们先前的认识，即HIV的GAG/POL和ENV编码区域内存在的RNA元素（称为INS）负责在没有REV的情况下核保留核保留和不稳定性，并且可以通过更改转录物的核苷酸组成来消除这些元素（RNA优化;还会序列化序列化）。通过修改抗原的运输，进一步改善了抗原的免疫力。引入的蛋白质修饰导致SIV抗原的更有效分泌，从而导致接种的小鼠或恒河猴的细胞和体液免疫反应增加。此类分子的免疫原性已在小鼠和猕猴中进行了测试。在小鼠中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的组合产生了更平衡的免疫反应，这是最佳AIDS疫苗的理想特征。正在测试HIV/SIV抗原的不同递送方法。艾滋病毒疫苗发育的另一个重要方面是选择抗原，必须考虑不同的HIV进化枝的多样性以及能够诱导相关免疫反应的关键表位的鉴定。我们正在使用使用保守的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疫苗向量能够诱导能够在恒河猴/SIV挑战模型中保护高病毒血症的有效免疫反应。使用DNA作为疫苗的局限性是肌内注射后其相对效率低下的递送。改善DNA输送的最新发展包括体内电穿孔。我们报告说，电穿孔大大提高了经验丰富的和艺术治疗的天真恒河猕猴的DNA递送效率，从而大大增加了抗原表达。我们发现，这种疫苗接种方法会导致具有高频率循环SIV特异性T细胞，多功能T细胞的存在以及效应器记忆和中央记忆CD4和CD8 SIV特异性T细胞的诱导，从而实现了增强的免疫反应。我们报告说，将IL-12 DNA作为辅助剂纳入了辅助质量的提高。除了系统性免疫反应外，这种改善的DNA疫苗接种方法的使用还诱导了粘膜反应，尽管仅对动物亚组。尽管DNA电穿孔提供了强烈的体液免疫反应，包括猕猴中的AB发育，但我们最近表明，蛋白质增强可以诱导更高水平的AB。重要的是，我们表明注射DNA和蛋白质在同一肌肉中未经辅助或佐剂同时增加了AB的产生和粘膜传播。 DNA和蛋白质共免疫优于疫苗接种，在引发体液免疫反应中，这两个单独的成分中的任何一个。也许更重要的是，该疫苗方案还引起了持久的长期体液免疫，可以在上次疫苗接种后4年检测到。接受此类优化疫苗接种方案的动物的挑战表明，病毒获取和改善了高度致病的SIV挑战的病毒学控制。因此，有效的DNA递送方法与改善的DNA疫苗鸡尾酒以及在疫苗方案中纳入蛋白质的蛋白质相结合，导致疫苗接种的恒河猕猴中的免疫反应大大增强和平衡。我们报道了全身和粘膜免疫反应与获取病毒的相关性以及细胞毒性细胞免疫反应与病毒控制的相关性。理想的HIV疫苗应提供针对所有HIV-1变体的保护。 HIV序列多样性以及潜在的免疫主导“诱饵”表位的存在是开发有效艾滋病疫苗的障碍。为了解决这些问题，我们正在探索最大化免疫力强度和广度的方法，专注于高度保守的艾滋病毒区域，以诱导对病毒功能的几乎不变蛋白质组片段的免疫反应，同时不包括对可变和潜在的免疫权利的“诱饵”的反应。我们开发了P24GAG（P24GAGCE DNA疫苗）内的原型疫苗靶向区域。在小鼠和猕猴的概念验看研究中，我们证明了这种DNA的免疫引起了针对CE的鲁棒细胞和体液免疫反应，这是p55gag DNA疫苗接种无法实现的。重要的是，我们证明，使用CE DNA进行启动并用p55gag DNA促进是一种有效的策略，可以最大程度地提高针对GAG的反应，从而提供了一种新颖的概念来增加疫苗接种的幅度和广度。与优化的GAG免疫原（p55GAG）相比，目前正在HVTN/DAIDS支持的临床试验中，目前正在采用这种新颖概念的翻译，目的是测试我们的P24GAGCE疫苗是否会发展出较高的呼吸和GAG反应的大小，这在HVTN临床试验中显示出最高的免疫反应率。