IDENTIFICATION OF A HIGHLY TRANSFECTABLE CELL LINE PERMISSIVE TO PORCINE EPIDEMIC DIARRHEA VIRUSINFECTION AND REPLICATION

摘要

Vero cell line has been routinely used for isolation and propagation of porcine epidemic diarrhea virus (PEDV), but isolation rate of PEDV in Vero cells has been demonstrated low, and the virus may gradually lose host infectivity upon in vitro passages. Besides, the entry mechanism of PEDV into Vero cells is also known to be cellular receptor (porcine amino-peptidase N; pAPN; CD13)-independent, which suggests that Vero cells might not be a suitable cell line for studying the interaction of PEDV withits receptor. To explore alternatives, a HEK 293 cell line stably expressing pAPN (HEK 293-pAPN) was established, and its susceptibility to PEDV infection was compared with Vero, HEK 293, and PK-15 cells. Interestingly, cytopathic effects characterized by cell fusion and multinuclear syncytial cells were observed in HEK 293, HEK 293-pAPN, and Vero cells after 48 h of inoculation, but not in PK-15 cells. Moreover, evidence of PEDV replication in these cell lines was also confirmed by immunocytochemistrystaining and real-time quantitative PCR analysis. In conclusion, we demonstrated that HEK 293 cells, regardless of overexpression of pAPN molecules, are permissive to PEDV. HEK 293 cell line with its highly transfectable characteristic might not only serve as an alternative tool for studying the entry mechanisms of PEDV, but also a replication permissive cell line for virus rescue such as from the infectious clone of PEDV. Furthermore, the identification of a cell line of human origin, HEK 293, permissive to PEDV raises the concern of possible interspecies transmission.