DNA Immunogens and Tolerogens

DNA 免疫原和耐受原

• 批准号: 6826915
• 负责人: Jack Ragheb
• 金额: --
• 依托单位: NATIONAL EYE INSTITUTE
• 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/6826915
• 关键词: AIDS vaccines; HIV envelope protein; autoimmunity; bacterial DNA; genetic manipulation; human immunodeficiency virus; laboratory mouse; laboratory rat; microorganism immunology; nonhuman therapy evaluation; oral tolerance; retinoid binding proteins; transfection /expression vector; uveitis; vaccine development; vector vaccine

DNA Immunogens and Tolerogens A. DNA Based Induction of Disease In the last several years it has been demonstrated that bacterial DNA itself is a potent adjuvant and that it can be used as a vaccine to induce immune responses (to protein antigens encoded by the DNA) that are sufficient to confer protective immunity against a number of pathogens. These observations suggest that so called DNA vaccines could also be used to induce diseases such as retinal degeneration or autoimmune uveitis in various animal models. One advantage of this previously untested approach is that it allows for the rapid screening of candidate disease targets (in their DNA form) by circumventing the need to isolate protein. This is particularly advantageous when it is very difficult to obtain sufficient quantities of purified human proteins to use as immunogens. As a first test of this approach we attempted to establish a DNA vaccine based model of experimental autoimmune uveitis. To date we have shown in rodents that a DNA vaccine encoding human IRBP administered via the SQ, ID, or IM routes elicits a good immune response to the encoded antigen and that the immunized rats, but interestingly not the mice, develop disease. We are presently working to improve the responses that we have obtained in rats and extend them to the mouse by altering the targeting and delivery of these DNA immunogens. Investigations into the basis of the dichotomy between immune response and disease pathogenesis in the mouse should lend further insight into the variables that are responsible for disease penetrance.These studies are currently inactive due to a need to increase our efforts in other areas. B. DNA Based Treatment of Disease-Oral Tolerance Our earlier results suggested that oral administration of a human IRBP DNA vaccine slightly reduced the experimental autoimmune uveitis induced in mice by the human protein antigen administered with a very powerful adjuvant. Due to the marginal effects that were observed, this project will remain inactive until more robust approaches have been developed. C. HIV Vaccine The advent of highly active anti-retroviral therapy (HAART) has resulted in a dramatic decline in HIV associated disease in this country. However, there is already evidence that viral resistance to HAART has emerged, suggesting that we may see a return of AIDS. It is clear that the long term solution to HIV infection must include the development of an effective vaccine. For safety reasons, efforts to develop a vaccine have focused on using the recombinant protein subunit components of the virus. However, HIV is a heavily glycosylated virus and the complex carbohydrate structures that are present on its surface are likely to mask important epitopes. Along with investigators at the University of Pennsylvania, we are exploring an alternative strategy to generate immune responses against HIV associated carbohydrate antigens. Our collaborator has identified short peptide sequences that elicit humoral immune responses that strongly cross react with certain carbohydrates. To test whether such anti-carbohydrate responses can enhance an anti-HIV immune response, we have genetically engineered these so-called peptide mimetope sequences into the HIV envelope gene. We have found that the envelope constructs generated to date retain most of their biological activity. We intend to use gene therapy vectors to introduce the altered HIV envelope into mouse B cells and assess the immune response to the altered HIV envelope can then be assessed after transfer of the transduced B cells to a syngenic host. These studies are currently inactive due to a need to increase our efforts in other areas.

DNA免疫原子和耐元 A.基于DNA的疾病诱导 在过去的几年中，已经证明细菌DNA本身是一种有效的辅助药物，可以用作疫苗来诱导免疫反应（对由DNA编码的蛋白质抗原），足以赋予针对许多病原体的保护性免疫。这些观察结果表明，在各种动物模型中，所谓的DNA疫苗也可以用于诱导诸如视网膜变性或自身免疫性葡萄膜炎之类的疾病。这种先前未经测试的方法的优点是，它可以通过规避分离蛋白质的需求来快速筛选候选疾病靶标（以其DNA形式）。当很难获得足够数量的纯化人蛋白来用作免疫原子时，这尤其有利。作为对这种方法的首次测试，我们试图建立基于DNA疫苗的实验自身免疫性葡萄膜炎模型。迄今为止，我们已经在啮齿动物中表明，通过SQ，ID或IM路线施用人IRBP的DNA疫苗会引起对编码抗原的良好免疫反应，并且免疫性大鼠，但有趣的不是小鼠，但不是小鼠发展疾病。目前，我们正在努力改善我们在大鼠中获得的反应，并通过改变这些DNA免疫原子的靶向和递送来扩展到小鼠。对小鼠免疫反应和疾病发病机理之间二分法的研究应进一步深入了解导致疾病渗透率的变量。这些研究目前由于需要增加我们在其他领域的努力而进行的研究。 B.基于DNA的疾病耐受性治疗 我们的早期结果表明，口服人IRBP DNA疫苗略微降低了用非常强大的佐剂施用的人蛋白抗原引起的小鼠诱导的实验性自身免疫性葡萄膜炎。由于观察到的边际效应，该项目将保持不活跃，直到开发出更健壮的方法。 C. HIV疫苗 高度活跃的抗逆转录病毒疗法（HAART）的出现导致该国艾滋病毒相关疾病的急剧下降。但是，已经有证据表明对Haa​​rt的病毒抵抗已经出现，这表明我们可能会看到艾滋病的回归。显然，艾滋病毒感染的长期解决方案必须包括开发有效的疫苗。出于安全原因，开发疫苗的努力专注于使用该病毒的重组蛋白亚基成分。然而，HIV是一种严重的糖基化病毒，其表面上存在的复杂碳水化合物结构可能掩盖了重要的表位。与宾夕法尼亚大学的研究人员一起，我们正在探索一种针对HIV相关碳水化合物抗原的免疫反应的替代策略。我们的合作者已经确定了短肽序列，这些肽序列引起了与某些碳水化合物反应强烈反应的体液免疫反应。为了测试这种抗碳水化合物反应是否可以增强抗HIV免疫反应，我们已经将这些所谓的肽Mimetope序列设计为HIV包膜基因。我们发现，迄今为止生成的信封构造保留了其大部分生物学活性。我们打算使用基因疗法向量将改变的HIV包膜引入小鼠B细胞中，并评估在转移转导的B细胞向合成宿主转移后，可以评估对改变的HIV包膜的免疫反应。这些研究目前由于需要增加我们在其他领域的努力而无效。