Development of an VEE Replicon Vaccine Against Smallpox

描述（由申请方提供）：拟定研究的目的是使用源自委内瑞拉马脑炎（VEE）病毒减毒株的单循环甲病毒复制子疫苗载体开发一种安全有效的天花疫苗。初步研究已经确定了候选的牛痘病毒（VACV）基因，当在动物中表达时，在小鼠和非人灵长类动物痘病毒攻击模型中引发保护性免疫应答。具体目的是（1）使用符合GMP的质粒载体构建表达VACV L1 R、A33 R、B5 R和A27 L基因（4pox）的VRP疫苗并产生VACV特异性试剂，（2）在小鼠和非人灵长类痘病毒攻击模型中评价表达VACV基因的VRP疫苗的安全性、免疫原性和有效性，（3）对表达VACV基因的VRP疫苗的GMP合规性生产工艺进行规模化开发，以及（4）生产适用于临床评价的GMP合规性4痘VRP疫苗，并进行基准IND使能研究。天花被证实已被根除，随后据推测世界上除两种天花病毒外的所有天花病毒库存都被销毁，导致大多数天花疫苗接种计划停止。因此，今天世界上大多数人对天花几乎没有免疫力。正痘病毒仍然是一个令人担忧的问题，原因有很多，包括正痘病毒被用作生物武器的威胁。正痘病毒所造成的大部分威胁可以通过接种疫苗来消除;然而，由于天花疫苗是一种活的正痘病毒，因此疫苗本身可能对免疫功能正常的个体尤其是免疫功能低下的个体造成严重的健康风险。基于拟议的研究，将通过临床前免疫原性和有效性研究、中试批次生产、GMP生产和GLP合规性毒理学研究以及支持未来IND提交所需的其他基准研究，来进行安全有效的替代天花疫苗。

DESCRIPTION (provided by applicant): The objective of the proposed research is to develop a safe and effective vaccine for smallpox using a single-cycle, alphavirus replicon vaccine vector that has been derived from attenuated strains of Venezuelan equine encephalitis (VEE) virus. Preliminary studies have identified candidate vaccinia virus (VACV) genes that, when expressed in animals, elicit a protective immune response in both mouse and nonhuman primate poxvirus challenge models. The specific aims are (1) to construct VRP vaccines expressing VACV L1R, A33R, B5R and A27L genes (4pox) using GMP-compliant plasmid vectors and generate VACV-specific reagents, (2) to evaluate safety, immunogenicity and efficacy of VRP vaccines expressing VACV genes in both mouse and nonhuman primate poxvirus challenge models, (3) to perform scale-up development of processes for GMP-compliant manufacture of VRP vaccines expressing VACV genes, and (4) to manufacture a GMP-compliant, 4pox VRP vaccine suitable for clinical evaluation and perform benchmark IND-enabling studies. The certified eradication of smallpox, followed by the presumed destruction of all but two of the world's stocks of variola virus, led to the cessation of most smallpox vaccination programs. As a result, most of the world's population today has little or no immunity to smallpox. Orthopoxviruses remain a concern for a number or reasons, including the threat of Orthopoxviruses used as biological weapons. Much of the threat posed by Orthopoxviruses could be eliminated by vaccination; however, because the smallpox vaccine is a live orthopoxvirus, the vaccine itself can pose serious health risks to both immunocompetent and especially immunocompromised individuals. Based on the proposed studies, a safe and effective alternative smallpox vaccine will be carried through preclinical immunogenicity and efficacy studies, pilot lot production, GMP manufacture and a GLP-compliant toxicology study and other benchmark studies needed to support a future IND submission.