Proportion of CD21
cells in cultures of PHA-P stimulated bovine PBMC after incubation with recombinant Shiga toxins and toxoids. Results are shown relative to data obtained from cultures incubated in the presence of the vector control (control cultures; defined as 1.0, indicated by the dashed line). Data is depicted as means ± standard deviations of 3 to 6 repetitive experiments as indicated. ANOVA was performed (1) comparing non-normalized data with the values from control cultures (asterisks above bars) and (2) comparing values of normalized data obtained after incubation with rStx1WT versus rStx1mut, rStx2WT versus rStx2mut, rStx1WT versus rStx2WT, and rStx1mut versus rStx2mut (asterisks above brackets). Significance levels were defined as p ≤ 0.001 [***], p ≤ 0.01 [**], and p ≤ 0.05 [*].