Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, TX, USA; Institute for Human Infections & Immunity, University of Texas Medical Branch, Galveston, TX, USA; Institute for Translational Science, University of Texas Medical Branch, Galveston, TX, USA.
Department of Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA.
Antiviral Res. 2019 Nov;171:104596. doi: 10.1016/j.antiviral.2019.104596. Epub 2019 Sep 4.
Zika virus (ZIKV) has drawn global attention as the etiologic agent of Zika Congenital Syndrome in babies born to infected pregnant women. To prevent future ZIKV outbreaks and protect persons at risk for severe disease, we developed two live-attenuated vaccine (LAV) candidates containing 10- or 20-nucleotide deletions in the 3'UTR of the viral genome (Δ10 and Δ20). After a single-dose immunization, both Δ10 and Δ20 LAVs protected mice and non-human primates against ZIKV infection. Here, we characterized the stability, safety, and efficacy of the LAVs after continuously culturing them on manufacture Vero cells for ten rounds. Whole genome sequencing showed that passage 10 (P10) LAVs retained the engineered Δ10 and Δ20 deletions; one to four additional mutations emerged at different regions of the genome. In A129 mice, the P10 LAVs exhibited viremia higher than the un-passaged LAVs, but lower than wild-type ZIKV; unlike wild-type ZIKV-infected mice, none of the P10 LAV-infected mice developed disease or death, demonstrating that the P10 LAVs remained attenuated. Mice immunized with a single dose of the P10 LAVs developed robust neutralizing antibody titers (1/1,000 to 1/10,000) and were protected against epidemic ZIKV challenge. The P10 LAVs did not exhibit increased neurovirulence. Intracranial inoculation of one-day-old CD1 pups with 10 focus-forming units of the P10 Δ10 and Δ20 LAVs resulted in 100% and ≥80% survival, respectively. Furthermore, the P10 LAVs remained incompetent in infecting Aedes aegypti mosquitoes after intrathoracic microinjection. Our results support the phenotypic stability and further development of these promising LAVs for ZIKV.
寨卡病毒（ZIKV）已引起全球关注，是感染孕妇所生婴儿的寨卡先天性综合征的病原体。为了防止未来的寨卡病毒爆发并保护易患严重疾病的人，我们开发了两种含有病毒基因组 3'UTR 中 10 或 20 个核苷酸缺失的减毒活疫苗（LAV）候选物（Δ10 和 Δ20）。单次免疫接种后，Δ10 和 Δ20 LAV 均可保护小鼠和非人灵长类动物免受 ZIKV 感染。在这里，我们对 LAV 在制造的 Vero 细胞上连续培养十代后的稳定性、安全性和功效进行了表征。全基因组测序显示，第 10 代（P10）LAV 保留了工程化的 Δ10 和 Δ20 缺失；在基因组的不同区域出现了一到四个额外的突变。在 A129 小鼠中，P10 LAV 的病毒血症高于未传代的 LAV，但低于野生型 ZIKV；与野生型 ZIKV 感染的小鼠不同，没有 P10 LAV 感染的小鼠出现疾病或死亡，表明 P10 LAV 仍然是减毒的。单次接种 P10 LAV 的小鼠产生了强大的中和抗体滴度（1/1000 至 1/10000），并能抵抗流行的 ZIKV 挑战。P10 LAV 未显示出增加的神经毒力。用 10 个焦点形成单位的 P10 Δ10 和 Δ20 LAV 对 1 天大的 CD1 幼鼠进行颅内接种，分别导致 100%和≥80%的存活率。此外，P10 LAV 在经胸内微注射后仍不能感染埃及伊蚊。我们的结果支持这些有前途的 LAV 在 ZIKV 方面的表型稳定性和进一步发展。
