Susceptibility of Cell Lines from Different Species to Porcine Deltacoronavirus

Porcine deltacoronavirus (PDCoV) is an emerging swine enteric coronavirus that causes severe diarrhea in piglets, leading to extensive economic losses in the global swine industry. Previous studies have reported that PDCoV can experimentally infect multiple animal species. However, the replication capability of PDCoV in non-natural host cell lines remains largely unknown. Herein, we investigated the effects of exogenous trypsin on PDCoV replication and systematically evaluated the susceptibility of various cell lines derived from human, murine, and feline to PDCoV. The results showed that highly permissive cell lines (H1299, Caco-2, MC-38) supported efficient viral replication without the requirement for exogenous trypsin, and high concentrations of trypsin induced prominent syncytia formation in infected H1299, U251, and Neuro-2a cells. Furthermore, this study also found that trypsin can enhance PDCoV replication in a concentration-dependent manner in semi-permissive cell lines. PDCoV can replicate in multiple cell lines of human, murine, and feline origin. Human cells (H1299, Caco-2) and murine MC-38 are highly susceptible to PDCoV infection, whereas MCF-7, TE-10, and KYSE-410 cells were completely non-permissive. The results also revealed a potential correlation between basal APN expression and cellular susceptibility to PDCoV. Collectively, this study provides a basis for assessing the interspecies transmission and zoonotic risk of PDCoV.