猪德尔塔冠状病毒TJ1株的分离鉴定及生物学特性分析

本研究旨在获得猪德尔塔冠状病毒（porcine deltacoronavirus，PDCoV）分离株，并对其生物学特性进行探讨。将RT-PCR检测PDCoV阳性样品无菌处理后接种猪肾（PK-15）细胞并连续传代培养，通过细胞病变、M基因序列分析及耐热、耐酸等试验对细胞培养物进行鉴定，采用Reed-Muench法测定PDCoV的TCID₅₀，应用5×10^4.0 TCID₅₀/mL的病毒悬液接种11日龄仔猪并观察临床症状。结果显示，试验成功分离到1株PDCoV，将其命名为TJ₁株，该病毒的第5代病毒效价为10^4.5 TCID₅₀/mL；TJ₁株对脂溶剂氯仿和乙醚不敏感，耐酸，在pH 3.0的环境下稳定，对热较敏感，在50℃条件下1 h便可将其灭活；其M基因和GenBank中已发表的PDCoV M基因核苷酸序列同源性为94%~99%；致病力试验结果显示，该病毒可引起仔猪发生腹泻，发病率100%。本研究成功分离了1株PDCoV毒株TJ₁株，对该分离株生物学特性进行初步研究，为进一步开展PDCoV相关研究奠定了基础。

Isolation,Identification and Biological Characteristics Analysis of Porcine Deltacoronavirus TJ1

The aim of this study was to obtain porcine deltacoronavirus (PDCoV) strain in China and study its biological characteristics. Porcine kidney (PK-15) cell monolayers were inoculated with the samples that were positive for PDCoV only by RT-PCR. PDCoV from the first passage was further serially passed in PK-15 cells. These cell cultures infected with PDCoV were confirmed by cytopathic effect (CPE), sequencing and analysis of PDCoV M gene, acid test; TCID₅₀ was confirmed by Reed-Muench method; The 11-day-old piglets were inoculated with 5×10^4.0 TCID₅₀/mL virus suspension and observed for clinical symptoms. The results indicated that the PDCoV was successfully isolated in cell culture and designated TJ₁, and the infectious titer of the 5th passage of TJ₁ strain was 10^4.5 TCID₅₀/mL; The isolated virus was resistant to chloroform and ether, it was stable at pH 3.0, and the virus was inactivated at 50℃ for 1 h; The TJ₁ M gene shared a homology of 94% to 99% with PDCoV M gene sequences published previously in GenBank; The animal pathogenicity test showed that diarrhea occurred in all piglets by TJ₁. This study successfully isolated a PDCoV TJ₁ strain, and these biological characteristics of the strain were studied preliminarily, which provided a foundation for further research on PDCoV.