FIG 8.

MERS-CoV-CD and MERS-CoV-mt undergo inefficient virus assembly in 293/CD26 cells. 293/CD26 cells were infected with MERS-CoV-WT (WT), MERS-CoV-CD (CD), or MERS-CoV-mt (mt) at an MOI of 3. (A) At the indicated time points postinfection, the titers of cell-associated viruses were determined by plaque assay. The results represent the averages of three independent experiments. Each bar represents the mean (± the standard deviation) for three samples. Asterisks represent statically significant differences between the titers of MERS-CoV-WT and mutant viruses (P < 0.05). Hash marks represent statically significant differences between the titers of MERS-CoV-CD and MERS-CoV-mt (P < 0.05). (B) At the indicated times postinfection, the total proteins were extracted and subjected to Western blot analysis using anti-human CD26 or tubulin antibody. Lysate of mock-infected 293 cells was included as a negative control in the far right lane of bottom panels. (C) At 36 h p.i., supernatants were collected and subjected to ⁶⁰Co irradiation. The purified viruses were pelleted, dissolved in the same volume of sample buffer, and subjected to Western blot analysis by using anti-S, -M, and -N protein antibodies.