FIG. 5.

Indirect effects of IFN-α on cytokine gene expression in IPEC-J2 cells. Pig tonsil cells were treated with rIFN-α at 0, 1, and 100 U/mL, at 37°C in 5% CO₂. Supernatants were harvested 18 h later and stored under aseptic conditions in aliquots at–80°C. IPEC-J2 cells at confluence were washed once with MEM medium and treated with 1:4 diluted tonsil supernatants for 18 h at 37°C in 5% CO₂. RNA of IPEC-J2 cells was extracted to evaluate the expression of IL-1β, TNF-α, IL-8, IL-6, and IFN-β genes. Data are expressed as 2^−ΔΔCt where ΔΔCt=(ΔCt of untreated cells)- (ΔCt of treated cells). The asterisks indicate significant differences between IPEC-J2 cells exposed to supernatants of control and IFN α-treated tonsil cells, respectively (one-way ANOVA). *P<0.05 ***P<0.001.