Figure 4

Expression of CD25 on CD4 ⁺CD45RO⁺ and CD8α^hiCD45RO⁺ cells after cultivation with ConA, Shiga toxoids or Listeria monocytogenes lysates. PBMC were isolated from calves in their 16^th and 26^th week of life, corresponding 8 and 18 weeks after active immunization with rStx_MUT. Animals were grouped according to their vaccination status (VAC+ = rStx_MUT-vaccinated; VAC− = placebo control) and the supplementation of vitamin E (VitE_H = high supplementation; VitE_M = moderate supplementation). Data obtained by flow cytometric analysis of the PBMC cultures after 5 days cultivation is depicted in box plots (5–95% interquartile ranges) as change of the geometric mean of fluorescence intensity of CD25 on CD4⁺CD45RO⁺ and CD8α^hiCD45RO⁺ relative to unstimulated control cells (the latter values defined as 0, indicated by the dashed line). Different letters indicate significant differences between the groups in CD4⁺CD45RO⁺ (lower case letters) and CD8α^hiCD45RO⁺ (capital letters) cells (p < 0.05, Kruskal–Wallis test with post hoc Dunn’s test).