Porcine enteric alphacoronavirus (PEAV) is a newly identified swine enteropathogenic coronavirus that causes watery diarrhea in neonatal piglets. The pathogenesis and host immune responses of PEAV infection are not fully characterized. The reason lies in the stomach environment, which would degrade cell-cultured live viruses via oral infection, making it difficult to establish an effective infection model to study the pathogenesis and host immune responses in pigs with a mature immune system. To solve this problem, in this study, coated PEAV-loaded microspheres were developed by centrifugal granulation-fluidized bed coating and demonstrated as an effective oral delivery system/animal infection model to protect PEAV virion against the complex gastrointestinal environment in vitro and to cause infection in weaned piglets in vivo. Weaned piglets orally inoculated with coated PEAV-loaded microspheres developed diarrhea and virus RNA was detected in rectal swabs from one to seven days post inoculation. In addition, microscopic lesions in the small intestine were observed, and viral antigens were also detected in the small intestines with PEAV immunohistochemical staining. Importantly, PEAV significantly inhibited mRNA expression of IFN-α, IFN-β, OAS, Mx1, and PKR, the genes involved in modulation of the host immune responses, in infected Peyer's patches, indicating that PEAV can overcome the antiviral response to cause damage when infection occurs. Collectively, our research successfully established a PEAV animal infection model in weaned piglets and suggested that the observed gene expression profile might help explain immunological changes associated with PEAV infection.

猪肠道α冠状病毒（PEAV）是一种新发现的猪肠道致病性冠状病毒，可引起新生仔猪水样腹泻。PEAV感染的发病机制和宿主免疫反应尚未完全表征。原因在于胃环境，这会降解细胞培养的活病毒通过口腔感染，很难建立有效的感染模型来研究具有成熟免疫系统的猪的发病机理和宿主免疫反应。为了解决这个问题，在这项研究中，通过离心造粒流化床包衣开发了负载包被的PEAV的微球，并被证明是有效的口服递送系统/动物感染模型，可以保护PEAV病毒体免受复杂的胃肠道环境的侵害。体外 并引起断奶仔猪的感染 体内。断奶的仔猪口服接种包被的PEAV的微球会导致腹泻，接种后1至7天在直肠拭子中检测到病毒RNA。另外，通过PEAV免疫组织化学染色，在小肠中观察到微观损伤，并且在小肠中还检测到病毒抗原。重要的是，PEAV明显抑制了干扰素α， 干扰素β， OAS，Mx1和 PKR感染宿主的Peyer斑中涉及调节宿主免疫反应的基因，表明PEAV可以克服抗病毒反应，从而在感染发生时造成损害。总体而言，我们的研究成功地在断奶仔猪中建立了PEAV动物感染模型，并表明观察到的基因表达谱可能有助于解释与PEAV感染相关的免疫学变化。