Experimental infection of gnotobiotic pigs with the cell-culture-adapted porcine deltacoronavirus strain OH-FD22.
Porcine deltacoronavirus (PDCoV) is a novel enteropathogenic coronavirus in pigs. We have isolated and passaged the PDCoV strain OH-FD22 in an LLC porcine kidney (LLC-PK) cell line. Our study investigated the pathogenicity of the tissue-culture-grown PDCoV (TC-PDCoV) OH-FD22 at cell passages 5, 20 and 40 in LLC-PK cells, in eight 14-day-old gnotobiotic (Gn) pigs. Pigs (n = 3) were euthanized for pathologic examination at post-inoculation day (PID) 3, and the remainder were monitored for clinical signs, virus shedding, and serum antibody responses until PID 28. All inoculated pigs developed watery diarrhea and/or vomiting at PID 1-2 and shed the highest amount of viral RNA in feces at PID 3-5, accompanied by severe atrophic enteritis. They developed high titers of PDCoV-specific IgG/IgA and virus-neutralizing antibodies in serum at PID 23-24. Histologic lesions were limited to the villous epithelium of the jejunum and ileum at PID 3. Two inoculated pigs tested at PID 23-24 had small to moderate numbers of PDCoV antigen-positive cells in the intestinal lamina propria and mesenteric lymph nodes, but not in enterocytes. An analysis of full-length S and N genes of TC- and Gn-pig-passaged OH-FD22 revealed a high genetic stability in cell culture and pigs. TC-PDCoV OH-FD22 (cell passages 5, 20 and 40) was enteropathogenic, and the pathogenicity was similar to that of the original field virus. The TC-PDCoV OH-FD22 will be useful for further pathogenesis studies and for evaluating if higher-level cell-culture passaged virus becomes attenuated for vaccine development.
Food Animal Health Research Program, Ohio Agricultural Research and Development Center, Department of Veterinary Preventive Medicine, The Ohio State University, 1680 Madison Ave., Wooster, OH, 44691, USA.|College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002, China.
Hui
H
Hu
Food Animal Health Research Program, Ohio Agricultural Research and Development Center, Department of Veterinary Preventive Medicine, The Ohio State University, 1680 Madison Ave., Wooster, OH, 44691, USA.
Kwonil
K
Jung
Food Animal Health Research Program, Ohio Agricultural Research and Development Center, Department of Veterinary Preventive Medicine, The Ohio State University, 1680 Madison Ave., Wooster, OH, 44691, USA.
Anastasia N
AN
Vlasova
Food Animal Health Research Program, Ohio Agricultural Research and Development Center, Department of Veterinary Preventive Medicine, The Ohio State University, 1680 Madison Ave., Wooster, OH, 44691, USA. saif.2@osu.edu.
Linda J
LJ
Saif
D000220:Adaptation, Biological; D032761:Animal Experimentation; D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood; D002460:Cell Line; D017934:Coronavirus / Q000302:isolation & purification* / Q000472:pathogenicity; D018352:Coronavirus Infections / Q000473:pathology / Q000662:veterinary* / Q000821:virology; D003967:Diarrhea / Q000473:pathology / Q000662:veterinary* / Q000821:virology; D005243:Feces / Q000821:virology; D042822:Genomic Instability; D005856:Germ-Free Life; D006651:Histocytochemistry; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007413:Intestinal Mucosa / Q000473:pathology; D007583:Jejunum / Q000473:pathology; D017422:Sequence Analysis, DNA; D012692:Serial Passage; D013552:Swine; D013553:Swine Diseases / Q000473:pathology* / Q000821:virology*; D014764:Viral Proteins / Q000235:genetics; D017201:Virus Shedding
D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D014764:Viral Proteins