Cytokine transcript levels in yearling gastric lymph node. Relative cytokine transcript levels in samples of gastric lymph node, in comparison to ATPase, from naïve and previously infected yearling sheep (Scottish Blackface × Bluefaced Leicester and Dorset × Suffolk) following challenge with T. circumcincta. Previously infected sheep were orally infected with 2,000 L3 larvae three times per week for eight weeks. All sheep were treated with Levamisole (7.5 mg/kg) then challenged one week later with 50,000 L3 larvae and killed on day 0, 2, 5 or 10 following challenge. An additional group of naïve sheep were killed on day 21 following challenge. Analysed using Tukey’s test with a 95% confidence interval, n = 6 sheep per group for each time point. Significant difference between naïve and previously infected groups: *P < 0.05, **P < 0.01, ***P < 0.001. Significant difference between day 0 and corresponding day 2: #P < 0.05, ##P < 0.01.