Collaborative Development of a Vaccine against Cutaneous and Visceral Leishmanias

描述（由申请人提供）：利什曼原虫是一种原虫寄生虫，可在亚热带和热带地区导致严重和使人衰弱的疾病。目前还没有有效的疫苗，而且由于药物毒性、耐药性的产生、难以获得医疗服务和费用高昂，化疗也存在问题。利什曼原虫疫苗开发面临的挑战包括确定交叉保护抗原，防止不同种类和临床形式的利什曼原虫病，以及确定诱导免疫保护的最佳途径和疫苗配方。这一申请代表了三个致力于开发针对利什曼病的疫苗这一统一主题的实验室之间的合作努力。剑桥大学的Jenefer Blackwell博士的实验室已经在小鼠身上使用DNA疫苗来筛选100种独特的利什曼原虫基因，作为高剂量毒性L. major感染的候选疫苗。鉴定出14种新的、可复制的保护性抗原。威尔逊博士在爱荷华大学的实验室通过免疫血清和T细胞的cDNA文库筛选发现了六种新的抗原。麦克马洪-普拉特博士在耶鲁大学的实验室已经鉴定出四种抗原，并鉴定出它们对亚马逊乳杆菌和/或婴儿乳杆菌感染的保护作用。这总共产生了24种具有潜在保护作用的新型抗原，可用于亚单位疫苗。在抗原进入犬和/或人体试验之前，仍有几个问题需要解决，并已制定为本项目的三个具体目标：(1)使用符合GMP标准的DNA疫苗重新筛选来自三个合作实验室的24种候选疫苗进行标准化条件下的保护/交叉保护，并将前6-10种疫苗测试为高达6价的DNA疫苗；(2)使用两种特征良好的抗原（TryP和LACK）进一步评估添加DNA引物佐剂是否能改善标准化条件下针对不同物种/临床形式利什曼病的DNA/MVA引物-增强疫苗接种；(3)选择最佳抗原组合和递送系统，使多价交叉保护异源初增强疫苗进入犬、灵长类动物和人的临床试验。通过三个实验室的协调方法，我们将系统地开展针对几种利什曼原虫的临床前试验，目标是开发一种泛利什曼原虫保护性疫苗。

DESCRIPTION (provided by applicant): Leishmania are protozoan parasites that can lead to severe and debilitating disease in sub-tropical and tropical regions. There are no effective vaccines available, and chemotherapy is problematic because of drug toxicity, the development of resistance, poor access to medical care, and expense. Challenges facing Leishmania vaccine development include identification of antigens that cross-protect against the different species and clinical forms of leishmaniasis, and identification of the optimal route and formulation of vaccines to induce immune protection. This application represents a collaborative effort between three laboratories working on the unified theme of vaccine development against leishmaniasis. Dr. Jenefer Blackwell's lab at the University of Cambridge has used DNA vaccination in mice to screen 100 unique Leishmania genes as vaccine candidates against high dose virulent L. major infection. Fourteen novel and reproducibly protective antigens were identified. Dr. Wilson's lab at the University of Iowa has discovered six novel antigens through cDNA library screening with immune serum and T cells. Dr. McMahon-Pratt's lab at Yale University has identified four antigens and characterized them for protection against L. amazonensis and/or L. infantum infection. This yields a total of 24 potentially protective novel antigens that can contribute to a subunit vaccine. Before antigens can be taken forward into canine and/or human trials, several issues remain to be addressed, and have been formulated into the three specific aims of this project: (1) To re-screen the 24 candidate vaccines from the three collaborating laboratories for protection/ cross-protection under standardized conditions using DNA vaccines made to GMP standards, and to test the top 6-10 vaccines as up to 6-valent DNA vaccines; (2) To use two well characterized antigens (TryP and LACK) to further evaluate whether the addition of adjuvants with DNA priming improves DNA/MVA prime-boost vaccination against different species/clinical forms of leishmaniasis under standardized conditions; and (3) To choose the best combination of antigens and delivery system for a multi-valent cross-protective heterologous prime- boost vaccine that can be taken forward into canine, primate and human clinical trials. Through a coordinated approach in the three laboratories, we will systematically perform pre-clinical testing against several Leishmania species, with the goal of developing a pan-leishmania protective vaccine.