Development of an improved, low-cost polio vaccine (Ir-IPV)

摘要 经过几十年的努力，全球根除脊髓灰质炎病毒的运动已接近尾声。辐射；辐射 野生型PV-2已经获得认证，PV1和PV2可能在未来几年内被根除。许多 各组织和国家在这些努力中进行了合作，我们应该祝贺他们的奉献精神 和坚持不懈。口服脊髓灰质炎疫苗(OPV)一直是大规模疫苗接种的主力，因为它具有 低成本和激发强大而持久的免疫力的能力。然而，口服脊髓灰质炎病毒很快恢复到致病性 人类和疫苗接种者的表型分泌野生型病毒，可以感染天真的旁观者。此外, 这种病毒可以在免疫受损的人身上长期复制，这些人可以多年传播病毒。为 出于这些原因，口服脊髓灰质炎疫苗(OPV)正在被灭活脊髓灰质炎疫苗(IPV)所取代，这种疫苗也能刺激持久性 豁免权。不幸的是，IPV的每剂费用远远高于OPV(3-5美元对0.12美元的补贴 世界市场)。因为世界卫生组织和大多数国家都计划继续接种疫苗至少10年 在根除之后，疫苗将继续有市场。由于IPV的成本很高，努力 正在开发改进的、更便宜的IPV疫苗。 在第一阶段的SBIR中，我们测试了使用最近开发的一种更便宜的IPV的可行性 辐射灭活方法。一种重组的锰+2-十肽磷酸配合物(MDP) 耐辐射细菌耐辐射球菌保护蛋白质中的抗原部位免受氧化 破坏病毒和细菌病原体的DNA/RNA基因组的辐射剂量的损害。我们 假设新方法可以提高单位起始病毒的抗原性，因为它避免了 广泛的福尔马林孵育12-28天，通过自发蛋白破坏脊髓灰质炎抗原 降解和交联性表位。保持抗原性将增加 每毫克纯化的病毒可以产生，灭活过程的简化可以减少 成本更高。优化工艺，在保护蛋白质的同时100%灭活病毒感染性 衣壳蛋白，我们将照射后的PV2病毒归一化为商业疫苗中发现的D抗原浓度。 用照射过的PV2免疫的大鼠产生了强大的中和效价。正常人的1/32 照射剂量的PV2刺激的中和抗体水平与商业IPV的1倍剂量相似 产品。 我们建议将这些发现扩展到包括PV1和PV3，然后获得一种三价疫苗，该疫苗具有 刺激与IPV相同的中和抗体水平的每个成分的最小剂量。在……里面 除了降低成本，这种新型疫苗还将有两个额外的特点：使用减毒沙宾 菌株和冻干程序的发展。向Sabin菌株的过渡将减少 目前与生产大量致病菌株有关的生物危害风险。此功能可以 允许发展中国家不太成熟的公司或政府实验室制造自己的产品 疫苗。此外，沙宾菌株的使用可能会提高产品的接受度，因为 与低水平的残留感染病毒相关的风险感知，这些病毒在质量上可能无法检测到 分析程序。冷冻干燥工艺的开发将提高产品的稳定性，从而使 疫苗在运输过程中不需要冷藏，并可能减少冷藏储存的需要。在……里面 此外，冻干疫苗在放入国家疫苗库存时可能会稳定多年。 我们已经与几位脊髓灰质炎疫苗专家和科学家讨论了第一阶段的结果，网址为 目前生产疫苗的公司。结果引起了人们的热情和兴趣 未来的互动。我们会在第二阶段让广大市民知道我们的进展，以便我们 可能在开发过程中比最初计划的更早提供合作选项。 该项目的主要目标是开发一种改进的、成本更低的脊髓灰质炎灭活疫苗。 然而，该项目也将使用一种高度特征化的病毒来推进辐射技术。相同 该方法可用于快速、高效地制备针对新出现的病原体的疫苗 如埃博拉、寨卡病毒和其他致命病原体。调控途径源于一种新的 在开发针对这些病毒的疫苗时，辐射灭活的光伏疫苗将是无价的。 具有病原体特征的。

Abstract After decades of effort, global campaigns to eradicate poliovirus are nearing completion. Eradiation of wild-type PV-2 has been certified and PV1 and PV2 may be eradicated in the next few years. Many organizations and countries have collaborated in these efforts and are to be congratulated for their dedication and persistence. The oral polio vaccine (OPV) has been the workhorse of mass vaccination efforts because of its low cost and ability to stimulate robust and durable immunity. However, OPV quickly reverts to pathogenic phenotypes in the human and vaccinees secrete wild-type virus that can infect naïve bystanders. In addition, the virus can replicate chronically in immune compromised people who can shed virus for many years. For these reasons, OPV is being replaced by the inactivated polio vaccine (IPV) which also stimulates durable immunity. Unfortunately, IPV costs considerably more than OPV per dose ($3-5 vs $0.12 on the subsidized world market). Because the WHO and most countries have plans to continue vaccination for at least 10 years after eradication, there will continue to be a market for the vaccine. Because of the high cost of the IPV, efforts are underway to derive improved and less expensive IPV vaccines. In a Phase 1 SBIR, we tested the feasibility of producing a less expensive IPV using a recently developed radiation-inactivation method. A reconstituted Mn+2-decapeptide phosphate complex (MDP) from the radiation-resistant bacterium Deinococcus radiodurans protects antigenic sites in proteins from oxidative damage at radiation doses that obliterate DNA/RNA genomes of viral and bacterial pathogens. We hypothesized that the new method could increase the antigenicity per unit of starting virus because it avoids the extensive 12 - 28 day formalin incubation that damages the polio antigens by spontaneous protein degradation and cross-linking epitopes. Preservation of antigenicity would increase the number of doses that can be produced per milligram of purified virus and simplification of the inactivation process could reduce costs further. After optimizing the process for inactivating 100% of virus infectivity while protecting the protein capsid, we normalized the irradiated PV2 virus to the D antigen concentrations found in commercial vaccines. Rats immunized with irradiated PV2 developed robust neutralizing titers. A 1/32 fraction of the normal human dose of irradiated PV2 stimulated similar levels of neutralizing antibodies as a 1X dose of the commercial IPV product. We propose to extend these findings to include PV1 and PV3 and then derive a trivalent vaccine having the minimum dose of each component that stimulates equivalent neutralizing antibody levels as IPV. In addition to a reduction in cost, the novel vaccine will have two additional features: the use of attenuated Sabin strains and the development of lyophilization procedures. The transition to Sabin strains will reduce the biohazard risks currently associated with producing large quantities of pathogenic strains. This feature may allow less sophisticated companies or government labs in developing countries to manufacture their own vaccines. In addition, the use of the Sabin strains may improve acceptance of the product due to the reduced risk perception associated with low levels of residual infections virus that may not be detected in quality analysis procedures. The development of a lyophilization process would improve product stability such that the vaccine would not require refrigeration during shipping and may reduce the need for refrigerated storage. In addition, a lyophilized vaccine could be stable for many years when placed in national vaccine stockpiles. We have discussed the findings of the Phase I with several polio vaccine experts and scientists at companies that currently manufacture the vaccine. The results have been met with enthusiasm and interest for future interactions. We will keep the wider community informed of our progress during the Phase II so that we may have partnering options earlier in the development process than originally planned. The main goal of the project is to develop an improved and less expensive inactivated polio vaccine. However, the project will also advance the irradiation technology using a highly characterized virus. The same method could be applied to the rapid and efficient preparation of vaccines against newly emerging pathogens such as Ebola, Zika, and other deadly pathogens. The regulatory pathway derived from the development of a radiation-inactivated PV vaccine would be invaluable when developing vaccines against these less characterized pathogens.