Oral Delivery of DNA Vaccines

描述(申请人提供)：生物战病原体(BWP)可能具有严重的毒性和故意操纵的广泛抗原变异，并可能通过多种进入途径传播，因此需要成功的疫苗诱导比大多数普通病原体更高程度的免疫保护。肺部、胃肠道和皮肤表面暴露的风险最高。由于系统免疫通常独立于常见的粘膜免疫系统而产生反应，因此疫苗的设计必须诱导黏膜效应细胞，这些细胞在致敏后可以在一个隔室扩散到其他表面组织，从而使在可接近的部位接种疫苗也能在其他部位诱导免疫耐受。与其他疫苗靶标不同，在全身免疫反应控制和根除感染之前，可能可以耐受大量的局部病原体复制，BWP疫苗诱导的免疫反应理想地应该完全防止毒性或感染，或者在广泛复制发生之前迅速杀死粘膜中的任何病原体或受感染的细胞。皮肤、肺和肠道包含最大的潜在暴露表面积，因此是必须通过对微生物病原体或致病产品的强烈免疫反应来保护的自然目标。为了实现这一目标，必须设计出抗原性高度灵活的疫苗策略，并能够以强烈刺激粘膜免疫系统的方式提供疫苗。不幸的是，使用纯化的多肽、蛋白质亚单位和/或减毒或灭活病原体的传统疫苗方法不具备所有这些免疫学特征。此外，由于BWP的性质无法准确预测，因此需要一种通用方法来快速生产针对任何新修改的病原体的有效疫苗，而基因疫苗正是具有这种潜力，如果能够开发出诱导强烈的粘膜免疫反应的方法。我们建议研究口服DNA疫苗的方法，使用编码模式抗原的质粒、炭疽致死毒素的一段片段和细胞因子IL12来增强小鼠的免疫应答，特别是在粘膜和全身部位诱导抗体和细胞毒性T细胞应答。

DESCRIPTION (provided by applicant): Biological warfare pathogens (BWP) will potentially have severe toxicity and broad antigenic variation from deliberate manipulations and may be transmissible by numerous routes of entry, thus requiring successful vaccines to induce a much higher degree of immune protection than is needed for most ordinary pathogens. Pulmonary, gastrointestinal, and cutaneous surfaces have the highest risk of exposure. Since systemic immunity often develop responses independently of the common mucosal immune system, vaccines must be designed to elicit the mucosal effector cells that can disseminate after sensitization in one compartment to other surface tissues, enabling vaccination at an accessible site to induce immunologic resistance at other sites as well. Unlike other vaccine targets, for which substantial local pathogen replication may be tolerable before the systemic immune response controls and eradicates the infection, the immune response induced by a BWP vaccine should ideally prevent toxicity or infection entirely, or rapidly kill any pathogens or infected cells in the mucosa before extensive replication occurs. The skin, lung, and gut contain the largest surface areas of potential exposure, and are thus the natural targets that must be protected with vigorous immune responses to microbial pathogens or pathogenic products. To achieve this goal, vaccine strategies must be devised that are highly flexible antigenically and can be delivered in such a way that the mucosal immune system is strongly stimulated. Unfortunately, traditional vaccine methods using purified peptides, protein subunits, and/or attenuated or inactivated pathogens do not have all these immunological features. Furthermore, since the nature of BWP will not be precisely predictable, a general method for rapidly producing an effective vaccine for any newly modified pathogen is needed, and genetic vaccines have exactly this potential, if methods for induction of strong mucosal immune responses can be developed. We propose to investigate the properties of oral delivery methods for DNA vaccines using plasmids encoding model antigens, a fragment of anthrax lethal toxin, and the cytokine IL12 to enhance the development of immune responses in mice, with particular emphasis on eliciting antibody and cytotoxic T cell responses in both mucosal and systemic sites.