Li Delong, Du Qian, Wu Bin, Li Juejun, Chang Lingling, Zhao Xiaomin, Huang Yong, Tong Dewen
College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
Vaccine. 2017 Aug 24;35(36):4722-4729. doi: 10.1016/j.vaccine.2017.07.031. Epub 2017 Jul 26.
Porcine circovirus type 2 (PCV2) is the main pathogen of porcine circovirus associated disease (PCVAD), causing great economic losses in pig industry. In previous study, we constructed adenovirus vector vaccines expressing PCV2 Cap either modified with Intron A and WPRE, or CD40L and GMCSF, and evaluated all of these vaccines in mice and in pigs. Although Ad-A-C-W and Ad-CD40L-Cap-GMCSF could induce stronger immune responses than Ad-Cap, neither of them was better than commercial inactivated vaccine PCV2 SH-strain. In this study, secretory recombinant adenoviruses (Ad-A-spCap-W and Ad-A-spCD40L-spCap-spGMCSF-W) and non-secretory recombinant adenovirus Ad-A-CD40L-Cap-GMCSF-W were constructed, and identified by western blot and confocal laser microscope observation. The results of ELISA and VN showed that humoral immune responses induced by Ad-A-spCap-W and Ad-A-CD40L-Cap-GMCSF-W were not significantly different from SH-strain, but Ad-A-spCD40L-spCap-spGMCSF-W could induce significantly higher humoral immune response than SH-strain. Lymphocytes proliferative and cytokines releasing levels of Ad-A-spCap-W and Ad-A-CD40L-Cap-GMCSF-W were not significantly different from SH-strain, but Ad-A-spCD40L-spCap-spGMCSF-W was significantly higher than SH-strain. PCV2-challenge experiment showed that virus loads were significantly reduced in Ad-A-spCD40L-spCap-spGMCSF-W vaccinated group, and no obviously clinical and microscopic lesions were observed in Ad-A-spCD40L-spCap-spGMCSF-W vaccinated group. Altogether, these results demonstrate that recombinant adenovirus vaccine Ad-A-spCD40L-spCap-spGMCSF-W induces stronger immune responses and provides better protection than commercial inactivated vaccine PCV2 SH-strain, and suggest that Ad-A-spCD40L-spCap-spGMCSF-W could be a potential vaccine candidate against PCVAD.
猪圆环病毒2型（PCV2）是猪圆环病毒相关疾病（PCVAD）的主要病原体，给养猪业造成了巨大的经济损失。在先前的研究中，我们构建了表达经内含子A和土拨鼠肝炎病毒转录后调控元件（WPRE）修饰的PCV2 Cap蛋白的腺病毒载体疫苗，以及表达CD40L和粒细胞-巨噬细胞集落刺激因子（GMCSF）的腺病毒载体疫苗，并在小鼠和猪体内对所有这些疫苗进行了评估。尽管Ad-A-C-W和Ad-CD40L-Cap-GMCSF诱导的免疫反应比Ad-Cap更强，但它们都不比市售的PCV2 SH株灭活疫苗好。在本研究中，构建了分泌型重组腺病毒（Ad-A-spCap-W和Ad-A-spCD40L-spCap-spGMCSF-W）和非分泌型重组腺病毒Ad-A-CD40L-Cap-GMCSF-W，并通过蛋白质免疫印迹法和共聚焦激光显微镜观察进行鉴定。酶联免疫吸附测定（ELISA）和病毒中和试验（VN）结果表明，Ad-A-spCap-W和Ad-A-CD40L-Cap-GMCSF-W诱导的体液免疫反应与SH株无显著差异，但Ad-A-spCD40L-spCap-spGMCSF-W诱导的体液免疫反应明显高于SH株。Ad-A-spCap-W和Ad-A-CD40L-Cap-GMCSF-W的淋巴细胞增殖和细胞因子释放水平与SH株无显著差异，但Ad-A-spCD40L-spCap-spGMCSF-W明显高于SH株。PCV2攻毒实验表明，Ad-A-spCD40L-spCap-spGMCSF-W疫苗接种组的病毒载量显著降低，且该组未观察到明显的临床和微观病变。总之，这些结果表明重组腺病毒疫苗Ad-A-spCD40L-spCap-spGMCSF-W诱导的免疫反应更强，比市售的PCV2 SH株灭活疫苗提供了更好的保护，并表明Ad-A-spCD40L-spCap-spGMCSF-W可能是一种潜在的抗PCVAD疫苗候选物。
