Fig 1. Feline calicivirus (FCV) infection induces COX-2 mRNA and protein expression leading to the production of PGE₂.

(A and B) The mRNA expression levels of COX-1 and COX-2 genes (A), and viral RNA level (B) in CRFK cells infected with or without FCV (MOI, 1 FFU/cell) at the indicated time points were determined by quantitative real time PCR. For COX-1 and COX-2, mRNA levels were normalized to β-actin mRNA and are illustrated as a fold induction against that of the mock-infected cells. (C) Monolayers of CRFK cells were infected with or without FCV (MOI, 1 TCID₅₀/ml) for the indicated time points, and the levels of the COX-1, COX-2, and GAPDH proteins were analyzed by Western blot analysis. GAPDH was used as a loading control. The intensity of each target protein relative to GAPDH was determined by densitometric analysis and is indicated above each lane. (D) PGE₂ levels in supernatants harvested from cells infected with or without FCV (MOI, 1 FFU/cell) at the indicated time points were analyzed by ELISA. The levels of PGE₂ in supernatants were compared between mock-and FCV-infected groups. All data shown were from three independent experiments and are presented as means and standard errors of mean. Statistical differences were evaluated by one-way analysis of variance. *p < 0.05; **p < 0.001; ***p < 0.0001.