China Institute of Veterinary Drug Control, Beijing 100081, China.
Zhaoyuan Center for Disease Control and Prevention, Yantai 265400, China.
Viruses. 2023 Oct 10;15(10):2072. doi: 10.3390/v15102072.
Single or mixed infections of multiple pathogens such as avian hepatitis E virus (aHEV) and avian leukosis virus subgroup J (ALV-J) have been detected in numerous laying hens with severe liver injury in China. Thus, aHEV and immunosuppressive viruses are speculated to cause co-infections. In this study, co-infection with aHEV and fowl adenovirus (FAdV) was confirmed by nested RT-PCR and recombinase-aided amplification combined with gene sequencing in two flocks with severe liver injury. Subsequently, the two reference strains, aHEV and FAdV-4, were inoculated into LMH cells to identify their co-infection potential. Confocal microscopy revealed aHEV and FAdV-4 co-infected LMH cells. In addition, the replication dynamics of aHEV and FAdV-4 along with the expression levels of immuno-cytokines were measured. The results indicated colocalization of aHEV and FAdV-4 and inhibition of viral replication in LMH cells. The transcription levels of MDA5, Mx, OASL, and IFN-α were significantly upregulated in LMH cells, whereas those of immune-related factors induced by FAdV-4 were downregulated upon FAdV-4 and aHEV co-infection. These results confirmed the co-infection of aHEV and FAdV-4 in vitro and prompted the antagonistic pathogenic effects of FAdV-4 and aHEV, thereby providing novel insights into the counterbalancing effects of these viruses.
在中国，许多产蛋母鸡出现严重肝损伤，检测到多种病原体的单一或混合感染，如禽戊型肝炎病毒（aHEV）和禽白血病病毒 J 亚群（ALV-J）。因此，推测 aHEV 和免疫抑制性病毒可能会引起合并感染。本研究通过巢式 RT-PCR 和重组酶辅助扩增结合基因测序，在两群严重肝损伤鸡群中证实了 aHEV 和禽腺病毒（FAdV）的合并感染。随后，将两种参考株，aHEV 和 FAdV-4，接种到 LMH 细胞中，以鉴定它们的合并感染潜力。共聚焦显微镜显示 aHEV 和 FAdV-4 共感染 LMH 细胞。此外，还测量了 aHEV 和 FAdV-4 的复制动态以及免疫细胞因子的表达水平。结果表明 aHEV 和 FAdV-4 共定位并抑制了 LMH 细胞中的病毒复制。LMH 细胞中 MDA5、Mx、OASL 和 IFN-α 的转录水平显著上调，而 FAdV-4 和 aHEV 共感染时，FAdV-4 诱导的免疫相关因子的转录水平下调。这些结果证实了 aHEV 和 FAdV-4 在体外的合并感染，并提示了 FAdV-4 和 aHEV 的拮抗致病作用，从而为这些病毒的相互制衡作用提供了新的见解。
