Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine, 30559 Hannover, Germany.
Clinic for Swine, Small Ruminants and Forensic Medicine, University of Veterinary Medicine, 30173 Hannover, Germany.
Viruses. 2019 Sep 21;11(10):880. doi: 10.3390/v11100880.
Atypical porcine pestivirus (APPV) is a widely distributed pathogen causing congenital tremor (CT) in piglets. So far, no data are available regarding the humoral immune response against APPV. In this study, piglets and their sows from an affected herd were tested longitudinally for viral genome and antibodies. APPV genome was detected in the majority of the piglets (14/15) from CT affected litters. Transient infection of gilts was observed. Kinetics of E- and E2-specific antibodies and their neutralizing capacity were determined by recently (E) and newly (E2) developed antibody ELISAs and virus neutralization assays. Putative maternally derived antibodies (MDA) were detected in most piglets, but displayed only low to moderate neutralizing capacity (ND ≤ 112). Horizontal APPV transmission occurred when uninfected and infected piglets were mingled on the flat deck. Horizontally infected piglets were clinically inapparent and showed only transient viremia with subsequently consistently high E2 antibody levels. For piglets from CT affected litters, significantly lower neutralizing antibody titers were observed. Results indicate that E2 represents the main target of neutralizing antibodies. Characterization of the humoral immune response against APPV will help to provide valuable serological diagnosis, to understand the epidemiology of this novel pathogen, and to implement tailored prevention strategies.
非典型猪瘟病毒（APPV）是一种广泛分布的病原体，可导致仔猪先天性震颤（CT）。迄今为止，尚无关于针对 APPV 的体液免疫应答的数据。在本研究中，对来自受影响畜群的仔猪及其母猪进行了纵向病毒基因组和抗体检测。在 CT 受影响窝的大多数仔猪（14/15）中检测到 APPV 基因组。观察到后备母猪的短暂感染。通过最近（E）和新开发的（E2）抗体 ELISA 和病毒中和测定，确定了 E-和 E2-特异性抗体及其中和能力的动力学。在大多数仔猪中检测到假定的母源抗体（MDA），但仅显示出低至中度的中和能力（ND ≤ 112）。当未感染和感染的仔猪在平板上混合时，会发生水平 APPV 传播。水平感染的仔猪临床上无明显症状，仅短暂出现病毒血症，随后 E2 抗体水平持续升高。对于来自 CT 受影响窝的仔猪，观察到的中和抗体滴度明显较低。结果表明，E2 是中和抗体的主要靶标。对 APPV 体液免疫应答的特征描述将有助于提供有价值的血清学诊断，了解这种新型病原体的流行病学，并实施针对性的预防策略。
