FIG 5.

CO suppresses PRRSV replication in PAMs, and its anti-PRRSV activity is independent of HO-1 induction. (A to C) PAMs were infected with PRRSV at an MOI of 0.1 for 1 h and then incubated in the presence or absence of the indicated concentrations of CORM-2 (50 to 150 μM) or iCORM-2 (150 μM) for 24 h. The levels of ORF7 mRNA (A), N protein (B), and virus titers (C) were assayed by qPCR, Western blotting, and TCID₅₀ determination, respectively. (D to F) MARC-145 cells or PAMs were treated with various concentrations of CORM-2 (50 to 150 μM) or iCORM-2 (150 μM) for 24 h. The cells were then harvested, and the abundance of HO-1 mRNA was determined by qPCR (D) and the expression of HO-1 protein was detected by Western blotting (E and F). Data are expressed as the means ± SD of the results of three independent experiments. P values were calculated using ANOVA. *, P < 0.05; ***, P < 0.001; ns: not significant.