title: Enhanced cell fusion activity in porcine epidemic diarrhea virus adapted to suckling mice.
abstract: Porcine epidemic diarrhea virus (PEDV) is the major causative agent of fatal diarrhea in piglets. To study the pathogenic features of PEDV using a mouse model, PEDV with virulence in mice is required. In pursuit of this, we adapted a tissue-culture-passed PEDV MK strain to suckling mouse brains. PEDV obtained after ten passages through the brains (MK-p10) had increased virulence for mice, and its fusion activity in cultured cells exceeded that of the original strain. However, the replication kinetics of MK and MK-p10 did not differ from each other in the brain and in cultured cells. The spike (S) protein of MK-p10 had four amino acid substitutions relative to the original strain. One of these (an H-to-R substitution at residue 1,381) was first detected in PEDV isolated after eight passages, and both this virus (MK-p8) and MK-p10 showed enhanced syncytium formation relative to the original MK strain and viruses isolated after two, four, and six passages, suggesting the possibility that the H-to-R mutation was responsible for this activity. This mutation could be also involved in the increased virulence of PEDV observed for MK-p10.
authors.affiliation: Department of Virology III, Laboratory of Acute Respiratory Viral Diseases and Cytokines, Musashimurayama, Tokyo, Japan.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Shirato
authors.forename: Madoka
authors.initials: M
authors.lastname: Maejima
authors.forename: Asuka
authors.initials: A
authors.lastname: Hirai
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Ami
authors.forename: Natsumi
authors.initials: N
authors.lastname: Takeyama
authors.forename: Kotaro
authors.initials: K
authors.lastname: Tsuchiya
authors.forename: Kouich
authors.initials: K
authors.lastname: Kusanagi
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Nunoya
authors.forename: Fumihiro
authors.initials: F
authors.lastname: Taguchi
mesh_terms: D000220:Adaptation, Biological; D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D001921:Brain / Q000821:virology; D002459:Cell Fusion; D002478:Cells, Cultured; D004195:Disease Models, Animal; D005260:Female; D008562:Membrane Glycoproteins / Q000235:genetics; D051379:Mice; D008813:Mice, Inbred ICR; D053485:Porcine epidemic diarrhea virus / Q000235:genetics / Q000472:pathogenicity*; D011247:Pregnancy; D012692:Serial Passage; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins / Q000235:genetics; D014774:Virulence
chemical_list: D008562:Membrane Glycoproteins; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins; C578557:spike glycoprotein, SARS-CoV; C578553:spike protein, mouse hepatitis virus
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