Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.
Department of Morphology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.
Viruses. 2020 Apr 5;12(4):402. doi: 10.3390/v12040402.
Porcine epidemic diarrhea virus (PEDV) and transmissible gastroenteritis virus (TGEV) have been reported to use aminopeptidase N (APN) as a cellular receptor. Recently, the role of APN as a receptor for PEDV has been questioned. In our study, the role of APN in PEDV and TGEV infections was studied in primary porcine enterocytes. After seven days of cultivation, 89% of enterocytes presented microvilli and showed a two- to five-fold higher susceptibility to PEDV and TGEV. A significant increase of PEDV and TGEV infection was correlated with a higher expression of APN, which was indicative that APN plays an important role in porcine coronavirus infections. However, PEDV and TGEV infected both APN positive and negative enterocytes. PEDV and TGEV Miller showed a higher infectivity in APN positive cells than in APN negative cells. In contrast, TGEV Purdue replicated better in APN negative cells. These results show that an additional receptor exists, different from APN for porcine coronaviruses. Subsequently, treatment of enterocytes with neuraminidase (NA) had no effect on infection efficiency of TGEV, implying that terminal cellular sialic acids (SAs) are no receptor determinants for TGEV. Treatment of TGEV with NA significantly enhanced the infection which shows that TGEV is masked by SAs.
猪流行性腹泻病毒（PEDV）和传染性胃肠炎病毒（TGEV）已被报道使用氨肽酶 N（APN）作为细胞受体。最近，APN 作为 PEDV 受体的作用受到质疑。在本研究中，我们在原代猪肠细胞中研究了 APN 在 PEDV 和 TGEV 感染中的作用。培养 7 天后，89%的肠细胞呈现微绒毛，对 PEDV 和 TGEV 的敏感性增加了两到五倍。APN 的高表达与 PEDV 和 TGEV 感染的显著增加相关，这表明 APN 在猪冠状病毒感染中发挥重要作用。然而，PEDV 和 TGEV 感染了 APN 阳性和阴性肠细胞。APN 阳性细胞中的 PEDV 和 TGEV Miller 显示出比 APN 阴性细胞更高的感染性。相比之下，TGEV 普渡在 APN 阴性细胞中复制得更好。这些结果表明，猪冠状病毒存在不同于 APN 的额外受体。随后，用神经氨酸酶（NA）处理肠细胞对 TGEV 的感染效率没有影响，这表明末端细胞唾液酸（SAs）不是 TGEV 的受体决定因素。用 NA 处理 TGEV 显著增强了感染，表明 TGEV 被 SAs 掩盖。
