A Novel Scrambled Antigen DNA Vaccine (SAVINE) Strategy

描述(由申请人提供)：经过20年对艾滋病毒疫苗开发的紧张研究，最近在几种商业上可行的候选疫苗上的成功现在带来了希望。DNA和被痘病毒增强的DNA都诱导了强大的T细胞反应，并赋予了猕猴部分保护作用。然而，与必须克服的障碍相比，这些成就是有限的，以保护不同的人类群体免受艾滋病毒分离株的影响，这些分离株比这些研究中使用的病毒更具变异性。伊恩·拉姆肖和斯科特·汤普森开发的新型疫苗Savine(杂乱抗原疫苗)解决了这一问题。Savine疫苗是由来自所有病毒结构和调控基因的随机重排的重叠多肽片段(30个氨基酸和15个氨基酸重叠)组成的，采用系统和合成的方法，其中T细胞表位的大小和处理机制是确定抗原如何被破坏的主要标准。重要的是，没有做出任何努力使设计偏向于已知的T细胞表位。因此，不需要知道特定的病毒表位和高危人群的主要人类白细胞抗原单倍型。在这项应用中，我们建议使用艾滋病SIV猕猴模型来评估Savine方法的免疫原性和有效性。将通过比较典型HIV Savine与标准B分支疫苗(目标1和3)中存在的序列和免疫原性来优化Savine的组成。利用这些信息，SIV Savines将由Savine疫苗方法的创始人Scott Thompson博士和Ian Ramshaw博士(目标2)构建。一旦SIV Savine疫苗在小鼠身上被证明是免疫原性的(目标2)，将评估它们在猕猴身上诱导粘膜和系统免疫反应以及提供粘膜保护的能力(目标4)。将确定Savine DNA和Savine Apox单独和组合诱导粘膜和全身免疫反应的能力。通过联合传递大肠杆菌肠毒素基因，DNA疫苗将进一步得到加强，我们最近证明，这种组合可以显著增强猕猴全基因免疫诱导的T细胞反应。T细胞反应的广度和大小将在外周和肠道相关组织(空肠固有层、肠系膜淋巴结)中进行评估，以便确定诱导粘膜反应的最佳策略，以及这些反应与保护的关系。粉末疫苗将评估小鼠和猴子的免疫反应，以便这些反应可以直接相互比较，并与其他DNA疫苗的历史数据进行比较。虽然其他研究表明，DNA：禽痘联合策略比单独接种任何一种疫苗都能诱导更好的全身免疫反应，但这是第一次，联合DNA：禽痘策略诱导粘膜免疫反应的能力将直接与单独使用任何一种方法进行比较。由于全身反应往往不能很好地预测粘膜反应，这些研究应该为HIV疫苗的开发提供重要的新信息。总而言之，这些实验将提供将这些研究转化为人体试验所必需的数据。

DESCRIPTION (provided by applicant): After two decades of intense research in HIV vaccine development, recent successes with several commercially viable vaccine candidates now offer hope. Both DNA, and DNA boosted with poxvirus, have induced robust T cell responses and conferred partial protection macaques. These achievements are modest, however, when compared to the obstacles that must be overcome to protect diverse human populations from HIV isolates that are considerably more hypervariable than the viruses used in these studies. SAVINE (scrambled antigen vaccine), a novel vaccine developed by Ian Ramshaw and Scott Thompson, addresses this concern. SAVINE vaccines are composed of randomly rearranged overlapping peptide fragments (30 amino acids overlapping by 15 amino acids) from all viral structural and regulatory genes using a systematic and synthetic approach in which the size and processing mechanisms of T cell epitopes are the primary criteria for determining how antigens might be disrupted. Importantly, no effort is made to bias the design towards known T cell epitopes. Thus, specific viral epitopes, and the predominant HLA haplotype of the population at risk need not be known. In this application, we propose to evaluate the immunogenicity and efficacy of the SAVINE approach using the SIV macaque model for AIDS. SAVINE composition will be optimized by comparing the sequence and immunogenicity of a prototypic HIV SAVINE to those present in a standard clade B vaccine (aims 1 and 3). Using this information, SIV SAVINEs will be constructed by the founders of the SAVINE vaccine approach, Drs. Scott Thompson and Ian Ramshaw (aim 2). Once SIV SAVINE vaccines are proven immunogenic in mice (aim 2), they will be evaluated for their ability to induce both mucosal and systemic immune responses, and to confer mucosal protection, in macaques (aim 4). The ability of SAVINE DNA and SAVINE avipox, both alone and in combination, to induce mucosal, as well as systemic, immune responses will be determined. DNA vaccines will be further potentiated by co-delivery of the gene for E. coli enterotoxin, a combination that we have recently shown to significantly augment T cell responses induced by whole gene immunization in macaques. The breadth and magnitude of T cell responses will be evaluated in both periphery and gut associated tissues (jejunal lamina propria, mesenteric lymph nodes) so that the optimum strategy for inducing mucosal responses, and the relationship of these responses to protection, can be determined. Immune responses in both mice and monkeys will be evaluated by Powderject Vaccines so that these responses can be directly compared with each other, as well as to historical data with other DNA vaccines. Although other studies have shown that a combined DNA:avipox strategy induces better systemic immune responses than either vaccine alone, for the first time, the ability of the combined DNA: avipox strategy to induce mucosal immune responses will be directly compared to either approach alone. Because systemic responses are often poor predictors of mucosal responses, these studies should provide important new information in HIV vaccine development. Together, these experiments will provide data essential to the translation of these studies to human trials.