SARS-CoV Pathogenesis Is Regulated by a STAT1 Dependent but a Type I, II and III Interferon Receptor Independent Mechanism

Frieman, Matthew B.; Chen, Jun; Morrison, Thomas E.; Whitmore, Alan; Funkhouser, William; Ward, Jerrold M.; Lamirande, Elaine W.; Roberts, Anjeanette; Heise, Mark; Subbarao, Kanta; Baric, Ralph S.

129S6/SvEv wildtype and STAT12/2 mice (catalog number 002045-M-F) were obtained from Taconic Farms (Germantown, NY). For the mouse adapted SARS-CoV infections, Type I IFN receptor deficient (IFN alpha/beta receptor) (IFNAR12/2) mice were bred in at the UNC mouse facility (Chapel Hill, North Carolina). Type II IFN receptor deficient (IFN gamma receptor) (IFNGR2/2) mice (stock number 002702) were purchased from The Jackson Laboratories (Bar Harbor, ME). For the Urbani virus infections, IFNAR12/2 mice were obtained as a gift from Dr. Joan Durbin at Ohio State University and IFN alpha/beta/ gamma receptor double knockout (IFNAGR2/2) mice were bred at the NIH animal facility (Bethesda, MD). IFN-lambda receptor knockout mice (IL28Ra2/2, Zymogen, Seattle, Washington) were bred at the UNC Chapel Hill animal facility. Animal housing and care and experimental protocols were in accordance with all UNC-Chapel Hill Institutional Animal Care and Use Committee guidelines or NIH guidelines, depending where the experiments were performed. All animal studies were conducted in Animal Biosafety Level 3 laboratories using SealSafe Hepa-filtered caging and personnel wore personal protective equipment, including Tyvek suits and hoods and positive pressure HEPA-filtered air respirators. 10 week old mice were anesthetized with a mixture of ketamine/xylazine or isoflurane and intranasally infected with either PBS alone or 10 5 pfu/50 ml rMA15 or the recombinant or biological epidemic virus, icSARS or Urbani, in PBS (Invitrogen, Carlsbad, CA). Mice were monitored at 24 h intervals for virus-induced morbidity and mortality. Subsets of mice were euthanized at days 2, 5, and 9 post-infection (dpi) for characterization of rMA15 infection, while the less pathogenic Urbani virus infected animals were sampled on days 2, 3, 5, 9, 15, 22 and 29 postinfection. All tissues were analyzed for histopathology changes and for viral titers.