FIG 5.
Increased pathogenicity in ChinaGD01-infected mice. (A and B) Weight loss in Ad5-hDPP4-transduced WT C57BL/6 mice (A) and IFNAR−/− C57BL/6 mice (B) infected intranasally with 105 PFU of MERS-CoV ChinaGD01 or EMC/2012. (C) Lungs were harvested at days 3 and 5 p.i. Virus titers were determined by plaque assay. Student’s t test was used to analyze differences in mean values between groups. All results are expressed as means ± standard errors of the means (SEM). A P value of <0.05 was considered to be statistically significant (*, P ≤ 0.05; **, P ≤ 0.01). (D) Two-way antigenic cross-PRNT assay between ChinaGD01 and EMC/2012 was performed using sera harvested from mice challenged with different MERS-CoVs 15 days p.i. (E and F) A total of 39 cytokines, chemokines, transcription factors, and two housekeeping genes (hypoxanthine phosphoribosyltransferase [HPRT] and beta-actin) were selected for qRT-PCR. Representative genes are shown. (G) Histopathological damage. Lungs from B6 mice were removed at the indicated time points 3 p.i., fixed in zinc formalin, and embedded in paraffin. Sections were stained with hematoxylin and eosin (20×).