Effect ofL. johnsoniiL531 pretreatment on CD4+/−CCR6+/−T cells and CCR6+/−IFNγ+/−T cells in peripheral blood. Peripheral blood samples were collected from the indicated piglets at 0, 24, and 192 h after S. Infantis challenge. Representative dot plots show the percentages of A CD4+/− CCR6+/− cells and E CCR6+/− IFNγ+/− cells among CD3+ T cells at 24 h after infection. Flow cytometry analysis of the percentages of B CD4− CCR6+, C CD4+ CCR6+, D CD4+ CCR6− cells and F CCR6− IFNγ+, G CCR6+ IFNγ+, and H CCR6+ IFNγ− cells within the peripheral CD3+ T-cell population in the indicated piglets. Data are presented as the mean ± SEM for each time point. *P < 0.05 (Tukey’s test).