Haese Nicole, Brocato Rebecca L, Henderson Thomas, Nilles Matthew L, Kwilas Steve A, Josleyn Matthew D, Hammerbeck Christopher D, Schiltz James, Royals Michael, Ballantyne John, Hooper Jay W, Bradley David S
Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences (UND SMHS), Grand Forks, North Dakota, United States of America.
Virology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Ft. Detrick, Maryland, United States of America.
PLoS Negl Trop Dis. 2015 Jun 5;9(6):e0003803. doi: 10.1371/journal.pntd.0003803. eCollection 2015.
Andes virus (ANDV) and ANDV-like viruses are responsible for most hantavirus pulmonary syndrome (HPS) cases in South America. Recent studies in Chile indicate that passive transfer of convalescent human plasma shows promise as a possible treatment for HPS. Unfortunately, availability of convalescent plasma from survivors of this lethal disease is very limited. We are interested in exploring the concept of using DNA vaccine technology to produce antiviral biologics, including polyclonal neutralizing antibodies for use in humans. Geese produce IgY and an alternatively spliced form, IgYΔFc, that can be purified at high concentrations from egg yolks. IgY lacks the properties of mammalian Fc that make antibodies produced in horses, sheep, and rabbits reactogenic in humans. Geese were vaccinated with an ANDV DNA vaccine encoding the virus envelope glycoproteins. All geese developed high-titer neutralizing antibodies after the second vaccination, and maintained high-levels of neutralizing antibodies as measured by a pseudovirion neutralization assay (PsVNA) for over 1 year. A booster vaccination resulted in extraordinarily high levels of neutralizing antibodies (i.e., PsVNA80 titers >100,000). Analysis of IgY and IgYΔFc by epitope mapping show these antibodies to be highly reactive to specific amino acid sequences of ANDV envelope glycoproteins. We examined the protective efficacy of the goose-derived antibody in the hamster model of lethal HPS. α-ANDV immune sera, or IgY/IgYΔFc purified from eggs, were passively transferred to hamsters subcutaneously starting 5 days after an IM challenge with ANDV (25 LD50). Both immune sera, and egg-derived purified IgY/IgYΔFc, protected 8 of 8 and 7 of 8 hamsters, respectively. In contrast, all hamsters receiving IgY/IgYΔFc purified from normal geese (n=8), or no-treatment (n=8), developed lethal HPS. These findings demonstrate that the DNA vaccine/goose platform can be used to produce a candidate antiviral biological product capable of preventing a lethal disease when administered post-exposure.
安第斯病毒（ANDV）及类ANDV病毒是南美洲大多数汉坦病毒肺综合征（HPS）病例的致病原。智利最近的研究表明，恢复期人血浆的被动转移有望成为治疗HPS的一种方法。不幸的是，这种致命疾病幸存者的恢复期血浆供应非常有限。我们有兴趣探索利用DNA疫苗技术生产抗病毒生物制品的概念，包括用于人类的多克隆中和抗体。鹅产生IgY和一种可变剪接形式IgYΔFc，它们可以从蛋黄中高浓度纯化。IgY缺乏哺乳动物Fc的特性，而正是这些特性使得马、羊和兔产生的抗体在人体内具有反应原性。用编码病毒包膜糖蛋白的ANDV DNA疫苗对鹅进行免疫接种。所有鹅在第二次接种后都产生了高滴度的中和抗体，并通过假病毒中和试验（PsVNA）测量，在超过1年的时间里保持高水平的中和抗体。加强免疫接种导致中和抗体水平异常高（即PsVNA80滴度>100,000）。通过表位作图分析IgY和IgYΔFc表明，这些抗体对ANDV包膜糖蛋白的特定氨基酸序列具有高度反应性。我们在致命性HPS的仓鼠模型中检测了鹅源抗体的保护效力。从用ANDV（25 LD50）进行肌肉注射攻击5天后开始，将α-ANDV免疫血清或从鸡蛋中纯化的IgY/IgYΔFc皮下被动转移给仓鼠。免疫血清和鸡蛋来源纯化IgY/IgYΔFc分别保护了8只仓鼠中的8只和7只。相比之下，所有接受从正常鹅中纯化的IgY/IgYΔFc（n = 8）或未接受治疗（n = 8）的仓鼠都发展为致命性HPS。这些发现表明，DNA疫苗/鹅平台可用于生产一种候选抗病毒生物制品，在暴露后给药时能够预防致命疾病。
