Cytokine transcript levels in 5-month-old lamb abomasal mucosa. Relative cytokine transcript levels in samples of abomasal mucosa, in comparison to ATPase, from naïve and previously infected 5-month-old Dorset × Suffolk lambs following challenge with T. circumcincta. Previously infected lambs were orally infected with 2,000 L3 larvae three times per week for eight weeks. All lambs were treated with Levamisole (7.5 mg/kg) then challenged one week later with 50,000 L3 larvae and killed on day 0, 5, 10 or 21 following challenge. Analysed using Tukey’s test with a 95% confidence interval, n = 4–6 lambs per group for each time point. Significant difference between naïve and previously infected groups: *P < 0.05, **P < 0.01, ***P < 0.001.