College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, 163319, Heilongjiang Province, China.
Shandong New Hope Liuhe Group Co., Ltd., Qingdao, 266100, China.
Virol J. 2021 Mar 21;18(1):60. doi: 10.1186/s12985-021-01536-w.
DNA vaccine is one of the research hotspots in veterinary vaccine development. Several advantages, such as cost-effectiveness, ease of design and production, good biocompatibility of plasmid DNA, attractive biosafety, and DNA stability, are found in DNA vaccines.
In this study, the plasmids expressing bovine herpesvirus 1 (BoHV-1) gB, gC, and gD proteins were mixed at the same mass ratio and adsorbed polyethyleneimine (PEI) magnetic beads with a diameter of 50 nm. Further, the plasmid and PEI magnetic bead polymers were packaged into double carboxyl polyethylene glycol (PEG) 600 to use as a DNA vaccine. The prepared DNA vaccine was employed to vaccinate mice via the intranasal route. The immune responses were evaluated in mice after vaccination.
The expression of viral proteins could be largely detected in the lung and rarely in the spleen of mice subjected to a vaccination. The examination of biochemical indicators, anal temperature, and histology indicated that the DNA vaccine was safe in vivo. However, short-time toxicity was observed. The total antibody detected with ELISA in vaccinated mice showed a higher level than PBS, DNA, PEI + DNA, and PBS groups. The antibody level was significantly elevated at the 15th week and started to decrease since the 17th week. The neutralizing antibody titer was significantly higher in DNA vaccine than naked DNA vaccinated animals. The total IgA level was much greater in the DNA vaccine group compared to other component vaccinated groups. The examination of cellular cytokines and the percentage of CD4/CD8 indicated that the prepared DNA vaccine induced a strong cellular immunity.
The mixed application of plasmids expressing BoHV-1 gB/gC/gD proteins by nano-carrier through intranasal route could effectively activate long-term humoral, cellular, and mucosal immune responses at high levels in mice. These data indicate PEI magnetic beads combining with PEG600 are an efficient vector for plasmid DNA to deliver intranasally as a DNA vaccine candidate.
DNA 疫苗是兽医疫苗开发的研究热点之一。DNA 疫苗具有成本效益高、设计和生产简便、质粒 DNA 良好的生物相容性、有吸引力的生物安全性和 DNA 稳定性等优点。
本研究将表达牛疱疹病毒 1（BoHV-1）gB、gC 和 gD 蛋白的质粒以相同的质量比混合，并吸附在直径为 50nm 的聚乙烯亚胺（PEI）磁性珠上。然后，将质粒和 PEI 磁性珠聚合物包封在双羧基聚乙二醇（PEG）600 中，用作 DNA 疫苗。通过鼻腔途径将制备的 DNA 疫苗接种给小鼠，并在接种后评估小鼠的免疫反应。
在接种的小鼠肺部可以大量检测到病毒蛋白的表达，而在脾脏中很少检测到。生化指标、肛温及组织学检查表明，该 DNA 疫苗在体内是安全的，但存在短期毒性。ELISA 检测到接种小鼠的总抗体水平高于 PBS、DNA、PEI+DNA 和 PBS 组。接种后第 15 周时，抗体水平显著升高，第 17 周开始下降。与裸 DNA 接种动物相比，DNA 疫苗组的中和抗体滴度显著升高。DNA 疫苗组的总 IgA 水平明显高于其他成分疫苗组。细胞因子和 CD4/CD8 百分比的检测表明，所制备的 DNA 疫苗在小鼠中诱导了强烈的细胞免疫。
通过鼻腔途径用纳米载体混合应用表达 BoHV-1 gB/gC/gD 蛋白的质粒，可以有效地在小鼠中激活高水平的长期体液、细胞和黏膜免疫反应。这些数据表明，PEI 磁性珠结合 PEG600 是一种有效的质粒 DNA 载体，可作为候选 DNA 疫苗经鼻腔递送至体内。
