Evaluation Studies of a Dengue-2 DNA Vaccine in Monkeys

描述（由申请人提供）：登革热和登革出血热由四种血清型登革（DEN）病毒中的任何一种感染引起。这些疾病已成为全球公共卫生问题，每年影响1亿人。此外，DEN病毒是潜在的生物恐怖剂，因为既没有有效的治疗方法，也没有疫苗。因此，需要研究开发一种有效和安全的疫苗，以预防这些病毒引起的感染和疾病。本研究旨在研制一种能诱导恒河猴产生保护性免疫应答的DEN-2病毒DNA疫苗。我们的长期目标是开发四价DEN DNA疫苗。 我们的疫苗策略集中在登革热包膜上，因为这种蛋白质介导感染的早期结合和进入步骤。针对这种蛋白质的中和抗体（Nab）显示出对病原性病毒感染和疾病具有保护作用。在这项研究中，我们计划使用四种不同的疫苗接种方案，评估我们的DNA疫苗候选物Vec-D2（编码DEN-2的prM和env蛋白）在猴子中产生的免疫应答。猴将用单独的或吸收到聚丙交酯-共-乙交酯（PLG）微粒上的Vec-D2免疫，然后施用在MF 59或单独的MF 59中佐剂化的灭活DEN-2病毒加强。我们的假设是，Vec-D2诱导的免疫应答将通过将质粒DNA偶联至PLG而增强，并且这些应答可以通过在MF 59中施用灭活病毒而进一步增强。将通过ELISA、病毒中和、CTL和增殖试验监测免疫应答。还将确定由不同疫苗策略诱导的针对DEN-2病毒感染的保护水平：完全保护将通过不存在可检测的病毒血症和回忆性免疫应答来确定。这些研究结果将为设计和开发表达DEN-1、DEN-3和DEN-4包膜蛋白的DNA疫苗提供重要信息。

DESCRIPTION (provided by applicant): Dengue fever and dengue hemorrhagic fever result from the infection with any of the four serotypes of dengue (DEN) viruses. These diseases have become a global public health problem, affecting 100 million people anually. Moreover, DEN viruses are potential bioterrorism agents since neither an effective treatment nor vaccine is available. Thus, research is needed to develop an effective and safe vaccine that will prevent infection and disease caused by any of these viruses. The objective of this study is to develop a DNA vaccine capable of inducing protective immune responses in rhesus macaques against DEN-2 virus infection. Our long-term objective is to develop a tetravalent DEN DNA vaccine. Our vaccine strategy is focused on the dengue envelope because this protein mediates the early binding and entry steps of infection. Neutralizing antibodies (Nab) against this protein were shown to be protective against pathogenic virus infection and disease. In this study we plan to evaluate immune responses generated in monkeys by our DNA vaccine candidate, Vec-D2 which encodes prM and env proteins of DEN-2, using four different vaccination regimens. Monkeys will be immunized with Vec-D2 either alone or absorbed onto polylactide-co-glycolide (PLG) microparticles, followed by the administration of an inactivated DEN-2 virus boost adjuvanted in MF59 or MF59 alone. Our hypothesis is that immune responses induced by Vec-D2 will be enhanced by coupling the plasmid DNA to PLG and that these responses could be further boosted by administration of inactivated virus in MF59. Immune responses will be monitored by ELISA, virus neutralization, CTL and proliferation assays. The level of protection induced by the different vaccine strategies against DEN-2 virus infection will be also ascertained: Complete protection will be determined by the absence of detectable viremia and of anamnestic immune responses. Results obtained from these studies will provide important information for the design and development of DNA vaccines expressing the envelope protein of DEN-l, DEN -3 and DEN-4.