Immunohistochemical identification of Foxp3+ T cells within the abomasal mucosa during infection with T. circumcincta. (A) Single immunohistochemical (IHC) labeling of Foxp3 demonstrating a number of positive cells within the abomasal mucosa at 10 dpi (arrowhead). A high-power view of Foxp3+ cells is inset in the panel. The arrow indicates a T. circumcincta larva within the mucosa. (B) Isotype control. (C) Double IHC labeling of Foxp3 (green) and CD3 (red) in the abomasal mucosa at 10 dpi. Arrowheads indicate double positive cells. (D) High-power view of panel C demonstrating surface labeling of CD3 and nuclear labeling of Foxp3. (E) Numbers of Foxp3+ cells within the abomasal mucosa at 0, 5 and 10 dpi. (F) Numbers of CD3+ cells within the abomasal mucosa at 0, 5 and 10 dpi. (G) The proportions of CD3+ T cells within the abomasal mucosa expressing Foxp3 at 0, 5 and 10 dpi. *P < 0.05, **P < 0.01, ***P < 0.001 (one way ANOVA followed by the Tukey post hoc test for pairwise comparison of means). Panel (A) has been previously presented by the authors .