FIGURE 4.

Real-time quantification RT-PCR of cytokine gene expression. Chickens were immunized at 4 weeks of age, and the trachea and nasal tissues were sampled at 1 and 3 dpi. Total RNA was extracted and equal amounts of RNA (1 μg) were used for RT-PCR. Gene expression was normalized to the β-actin gene expression level and presented as the fold increase relative to PBS-treated chickens. Data represent the mean fold changes ± standard errors. Asterisks represent p-values < 0.05.