Evaluation Studies of a Dengue-2 DNA Vaccine in Monkeys

描述(申请人提供)：登革热和登革出血热是由感染四种登革热(登革热)病毒中的任何一种引起的。这些疾病已成为全球公共卫生问题，每年影响1亿人。此外，由于既没有有效的治疗方法，也没有疫苗，登革热病毒是潜在的生物恐怖主义病原体。因此，需要研究开发一种有效和安全的疫苗，以防止由任何这些病毒引起的感染和疾病。本研究的目的是开发一种DNA疫苗，能够诱导恒河猴对登革2型病毒感染的保护性免疫反应。我们的长期目标是开发一种四价登革病毒DNA疫苗。我们的疫苗策略专注于登革热包膜，因为这种蛋白介导了感染的早期结合和进入步骤。针对该蛋白的中和抗体(NAB)被证明对致病病毒感染和疾病具有保护作用。在这项研究中，我们计划评估我们的DNA疫苗候选VEC-D2在猴子身上产生的免疫反应，VEC-D2编码DEN-2的PRM和env蛋白，使用四种不同的免疫方案。猴子将单独或被聚乳酸-乙交酯(PLG)微粒吸收的VEC-D2免疫，然后单独注射MF59或MF59佐剂的灭活DEN-2病毒加强剂。我们的假设是，通过将质粒DNA偶联到PLG，VEC-D2诱导的免疫反应将被增强，并且这些反应可以通过在MF59中注射灭活病毒来进一步增强。免疫反应将通过酶联免疫吸附试验、病毒中和试验、CTL和增殖试验进行监测。还将确定不同疫苗策略对登革2型病毒感染的保护水平：完全保护将取决于没有可检测到的病毒血症和记忆免疫反应。这些研究结果将为设计和开发表达DEN-L、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.