Department of Veterinary Medicine, School of Veterinary Medicine, National Taiwan University, No. 1, Sec 4, Roosevelt Road, Taipei, 10617, Taiwan.
Graduate Institute of Veterinary Pathobiology, College of Veterinary Medicine, National Chung Hsing University, 145 Xingda Road, Taichung, 40227, Taiwan.
Vet Res. 2023 Jul 11;54(1):57. doi: 10.1186/s13567-023-01181-x.
Classical swine fever virus (CSFV) infection leading to CSF outbreaks is among the most devastating swine diseases in the pig industry. Porcine circovirus type 2 (PCV2) infection, resulting in porcine circovirus-associated disease (PCVAD), is also a highly contagious disease affecting pig health worldwide. To prevent and control disease occurrence, multiple-vaccine immunization is necessary in contaminated areas or countries. In this study, a novel CSFV-PCV2 bivalent vaccine was constructed and demonstrated to be capable of eliciting humoral and cellular immune responses against CSFV and PCV2, respectively. Moreover, a CSFV-PCV2 dual-challenge trial was conducted on specific-pathogen-free (SPF) pigs to evaluate vaccine efficacy. All of the vaccinated pigs survived and showed no clinical signs of infection throughout the experimental period. In contrast, placebo-vaccinated pigs exhibited severe clinical signs of infection and steeply increased viremia levels of CSFV and PCV2 after virus challenge. Additionally, neither clinical signs nor viral detections were noted in the sentinel pigs when cohabitated with vaccinated-challenged pigs at three days post-inoculation of CSFV, indicating that the CSFV-PCV2 bivalent vaccine completely prevents horizontal transmission of CSFV. Furthermore, conventional pigs were utilized to evaluate the application of the CSFV-PCV2 bivalent vaccine in field farms. An adequate CSFV antibody response and a significant decrease in PCV2 viral load in the peripheral lymph nodes were observed in immunized conventional pigs, suggesting its potential for clinical application. Overall, this study demonstrated that the CSFV-PCV2 bivalent vaccine effectively elicited protective immune responses and the ability to prevent horizontal transmission, which could be a prospective strategy for controlling both CSF and PCVAD in commercial herds.
经典猪瘟病毒（CSFV）感染导致的 CSF 爆发是养猪业中最具破坏性的猪病之一。猪圆环病毒 2 型（PCV2）感染导致猪圆环病毒相关疾病（PCVAD），也是一种在全球范围内影响猪健康的高度传染性疾病。为了预防和控制疾病的发生，在污染地区或国家需要进行多疫苗免疫接种。在本研究中，构建了一种新型的 CSFV-PCV2 二价疫苗，并证明其能够分别针对 CSFV 和 PCV2 产生体液和细胞免疫反应。此外，还在特定病原体无（SPF）猪上进行了 CSFV-PCV2 双重挑战试验，以评估疫苗的功效。所有接种疫苗的猪在整个实验期间均存活，没有感染的临床症状。相比之下，安慰剂接种的猪在病毒挑战后表现出严重的感染临床症状和急剧增加的 CSFV 和 PCV2 病毒血症水平。此外，在接种 CSFV 后三天与接种挑战猪同居的哨兵猪中，既没有观察到临床症状，也没有检测到病毒。这表明 CSFV-PCV2 二价疫苗完全阻止了 CSFV 的水平传播。此外，还利用常规猪评估了 CSFV-PCV2 二价疫苗在田间农场的应用。免疫的常规猪表现出足够的 CSFV 抗体反应和外周淋巴结中 PCV2 病毒载量的显著下降，表明其在临床上的应用潜力。总的来说，本研究表明，CSFV-PCV2 二价疫苗能够有效引发保护性免疫反应，并具有预防水平传播的能力，这可能是控制商业猪群中 CSF 和 PCVAD 的一种有前景的策略。
